Geologic Map of the Prescott National Forest and the Headwaters of ...

Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Yavapai and Coconino Counties, Arizona

By Ed DeWitt1, Victoria Langenheim1, Eric Force1, R.K. Vance2, P.A. Lindberg3, and R.L. Driscoll1

1U.S. Geological Survey

2Georgia Southern University, Statesboro, Ga.

3Consulting geologist, Sedona, Ariz.

Pamphlet to accompany

Scientific Investigations Map 2996

U.S. Department of the InteriorU.S. Geological Survey

U.S. Department of the InteriorDIRK KEMPTHORNE, Secretary

U.S. Geological SurveyMark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation:

DeWitt, Ed, Langenheim, Victoria, Force, Eric, Vance, R.K., Lindberg, P.A., and Driscoll, R.L., 2008, Geologic map of the Prescott National Forest and the headwaters of the Verde River, Yavapai and Coconino Counties, Arizona: U.S. Geological Survey Scientific Investigations Map 2996, scale 1:100,000, 100-p. pamphlet.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

ISBN 978-141132090-1

Contents

Description of Map Units ............................................................................................................................ 1Acknowledgments ..................................................................................................................................... 81References Cited ........................................................................................................................................ 81

Figures1. Index map showing extents of geologic map and boundary of Prescott National Forest ... 2

2–20. Major-element classification diagrams:2. For 4- to 6-Ma volcanic rocks north of Perkinsville ............................................................. 43. For 4- to 6-Ma volcanic rocks in northwest corner of map area ....................................... 5 4. For 4- to 6-Ma volcanic rocks near Paulden ......................................................................... 65. For 4- to 6-Ma volcanic rocks in Verde River valley and east of Sedona ......................... 7 6. For 8- to 10-Ma volcanic rocks at Hackberry Mountain and along Interstate 17 ........... 97. For 8- to 10-Ma volcanic rocks at Mt. Hope, west of map area ....................................... 108. For 8- to 10-Ma volcanic rocks west and northwest of Prescott, and from near Paulden ................................................................................................................... 119. For 10- to 15-Ma volcanic rocks of Hickey Formation near Prescott .............................. 14

10. For 10- to 15-Ma volcanic rocks of Hickey Formation in the Black Hills and northeast of Cordes Junction ................................................................................................ 1511. For 10- to 15-Ma volcanic rocks of Hickey Formation east and southeast of Sedona 1712. For 10- to 15-Ma volcanic rocks of Hickey Formation in Hackberry Mountain and Arnold Mesa areas .................................................................................................................. 18 13. For 10- to 15-Ma volcanic rocks of Hickey Formation near House Mountain ............... 19 14. For 10- to 15-Ma volcanic rocks in Milk Creek Formation near Wagoner and from a latite body south of Mayer ......................................................................................... 21 15. For 21- to 27-Ma volcanic rocks in Sullivan Buttes volcanic field ................................... 2316. For 21- to 27-Ma volcanic rocks in Sullivan Buttes volcanic field ................................... 2417. For 24- to 36-Ma volcanic rocks in Santa Maria Mountains, Juniper Mountains, and Martin Mountain ..................................................................................................................... 2518. For Paleocene and Late Cretaceous plutonic rocks in Bradshaw Mountains .............. 26 19. For 1,400-Ma plutonic rocks between Skull Valley and Juniper Mountains .................. 2920. For 1,400-Ma Dells Granite north of Prescott ...................................................................... 31

21. Index map showing locations of geochemical zones (1–6) in map area ............................... 32 22–49. Major-element classification diagrams:

22. For Early Proterozoic gabbros from zones 1–5 in Bradshaw Mountains and zone 6 in the Black Hills and near Dugas ............................................................................................ 3323. For Early Proterozoic gabbros from zone 2 in Bradshaw Mountains ............................. 3524. For Early Proterozoic gabbros from zone 3 in Bradshaw Mountains ............................. 3625. For Early Proterozoic gabbros from zone 4 in Bradshaw Mountains ............................. 3726. For Early Proterozoic gabbros from zone 5 in Bradshaw Mountains ............................. 38

iii

27. For Early Proterozoic gabbros and tonalite from zones 6A and 6B in the Black Hills and from zone 6B in Dugas area ................................................................................................... 39 28. For Early Proterozoic plutonic rocks from zones 1–6 in Bradshaw Mountains and the Black Hills ........................................................................................................................... 41 29. For Early Proterozoic plutonic rocks from zone 1 in Bradshaw Mountains ................... 4230. For Early Proterozoic plutonic rocks from zone 2 in Bradshaw Mountains ................... 43 31. For Early Proterozoic plutonic rocks from zone 3 in Bradshaw Mountains ................... 4432. For Early Proterozoic plutonic rocks from zone 4 in Bradshaw Mountains ................... 4533. For Early Proterozoic plutonic rocks from zone 5 in Bradshaw Mountains ................... 4634. For Early Proterozoic plutonic rocks from zone 6 in the Black Hills ................................ 47 35. For Early Proterozoic metavolcanic rocks in zones 1–5 in Bradshaw Mountains ........ 57 36. For Early Proterozoic metavolcanic rocks in zone 6 in the Black Hills ........................... 58 37. For unaltered Early Proterozoic metavolcanic rocks from zone 2 in Bradshaw Mountains ................................................................................................................................. 6038. For Early Proterozoic metavolcanic rocks from zone 3A in Bradshaw Mountains ...... 6139. For Early Proterozoic metavolcanic rocks from zone 3B in Bradshaw Mountains ...... 6240. For Early Proterozoic metavolcanic rocks from zone 4A in Bradshaw Mountains ...... 63 41. For Early Proterozoic metavolcanic rocks from zone 4B in Bradshaw Mountains ...... 64 42. For Early Proterozoic metavolcanic rocks from zone 4C in Bradshaw Mountains ...... 65 43. For Early Proterozoic metavolcanic rocks from zone 5A in Bradshaw Mountains ...... 66 44. For Early Proterozoic metavolcanic rocks from zone 5B in Bradshaw Mountains ...... 67 45. For Early Proterozoic metavolcanic rocks of intermediate to mafic composition from zone 6A in the Black Hills ....................................................................................................... 6846. For Early Proterozoic metavolcanic rocks of felsic to intermediate composition from zone 6A in the Black Hills and near Dugas .......................................................................... 69 47. For Early Proterozoic metavolcanic rocks of intermediate to mafic composition from zone 6B in the Black Hills ....................................................................................................... 70 48. For Early Proterozoic metavolcanic rocks of felsic to intermediate composition from zone 6B in the Black Hills ....................................................................................................... 7149. For hydrothermally altered Early Proterozoic felsic metavolcanic rocks south of Jerome ....................................................................................................................................... 79

Tables[Other tabular data not included in this pamphlet are spreadsheets for geochemistry and water wells; both files are available at http://pubs.usgs.gov/sim/2996]

1. Geochronologic data, in order of increasing age, for the map area .................................... 89 2. Deep water wells for which interpreted logs were provided by this study ................ 94

iv

Conversion Factors

________________________________________________________________To convert Multiply by To obtain________________________________________________________________meter (m) 3.281 foot (ft)kilometer (km) 0.6214 mile (mi)square kilometer (km2) 0.3861 square mile (mi2)________________________________________________________________

DESCRIPTION OF MAP UNITS

Qa Artificial fill—ManmadestructuresthatincludewastepilesandtailingspondsQal Alluvium (Holocene)—Sand,gravel,andsiltinpresent-daystreambeds.Includesminor

terracedepositsalongstreams.SimplifiedfromOstenaaandothers(1993)inBigChinoValleyandfromHouse(1994)andHouseandPearthree(1993)inVerdeRivervalley(fig.1).Thicknesshighlyvariable,2–20m

Qc Colluvium and sedimentary breccia (Holocene and Pleistocene)—Debrisflowsandminorlandslidedeposits

Qf Fanglomerate (Holocene and Pleistocene)—Poorlysortedgravelanddebrisflowsandminorlandslidedeposits.Includesmuchmedium-grained,limestone-richfanmaterialinBigChinoValley,northofBigChinoWash.Thicknesshighlyvariable,30–40m

Qt Terrace gravel (Holocene and Pleistocene)—Well-sortedgraveldepositsalongmajorstreams.SimplifiedfromOstenaaandothers(1993)inBigChinoValleyandfromHouse(1994)andHouseandPearthree(1993)inVerdeRivervalley.Thickness2–10m

Qg Gravel (Holocene and Pleistocene)—Well-sortedsandandgravelandminorconglomerate.SimplifiedfromOstenaaandothers(1993)inBigChinoValleyandfromHouse(1994)andHouseandPearthree(1993)inVerdeRivervalley.Thickness2–15m

Qs Sediment (Holocene and Pleistocene)—Siltandclaycontainingminordepositsofmixedsedimentandgravel.SimplifiedfromOstenaaandothers(1993)inBigChinoValley.Unknownthickness

QTl Landslide deposits (Holocene to Pliocene)—ChaoticblocksofTertiarybasaltandTertiarysedimentaryrocks,especiallyabundantinsouthwesternpartofmaparea,alongSyca-moreCreek,andinsoutheasternpartofmaparea,eastofVerdeRiver.Inplaces,maybeentirelyQuaternaryinage

QTf Fanglomerate (Pleistocene and Pliocene)—Poorlysortedgravelconglomeratethatcropsoutonnorth,east,andwestsidesofSullivanButtesaswellasinotherlocalitiesinmaparea.Gravelrichinlati-andesitefragments.Thickness10–150m

QTg Gravel (Pleistocene and Pliocene)—Poorlysortedgravelandconglomerate.Insouth-westernVerdeRivervalley,gravelcontainsangulartosemi-roundedTertiarybasaltandPaleozoiclimestoneandsandstonecobblesthatrestunconformablyonVerdeForma-tion.Thickness2–10m

QTs Sedimentary rocks (Pleistocene and Pliocene)—Siltstone,sandstone,andmixedsedimen-taryandvolcaniclasticrocks

Verde Formation (Pliocene and Miocene)—Fine-grainedclasticandchemicallyprecipi-tatedstratadepositedinlacustrineenvironment(Jenkins,1923;TwenterandMetzger,1963;Thompson,1983;Nationsandothers,1981).Twobasaltflows,onenearmouthofSycamoreCanyonandtheotheralongInterstate17,areinterbeddedwiththelake-bedsediments,butaredescribedamongtheyoungerbasalts.Thicknessofexposedrocksabout480m;thicknessofentireformationabout780m,butmayexceed950m.Ageabout2–7Ma(BresslerandButler,1978;McKeeandAnderson,1971)

Tvs Undivided sedimentary rocks—Includeslimestone,claystone,siltylimestone,andsilt-stone.Thicknessvariable

Tvl Lacustrine rocks—Includesclaystone,siltstone,andsiltylimestone.ThicknessvariableTvls Limestone—Limestoneandsiltylimestone.ThicknessvariableTvg Gravel—SiltylimestonethatcontainspebblesandcobblesofPaleozoicsandstoneand

limestoneandTertiarybasalt.AbundantonnorthwestandsoutheastmarginsofoutcropofVerdeFormation.Thicknessvariable

Tvt Travertine (Pliocene)—Coarse-grained,calcite-richtravertinemounds,especiallyabun-dantnearMontezumaWell,ineast-centralpartofoutcropsofVerdeFormation.Thick-nessabout10–35m

Tve Evaporite beds (Miocene)—Sulfate-richstratainterbeddedwithminorlimestoneandsiltstone(Thompson,1983).Sulfatemineralsincludeglauberite,gypsum,mirabillite,andthernardite.Thicknessabout10–35m

Tfy Fanglomerate (Pliocene)—PoorlysortedfanglomerateandconglomeratealongwestsideofBradshawMountains,fromGraniteMountaintosouthernboundaryofmaparea.

� Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Arizona

Figure 1. Extents of geologic map and boundary of the Prescott National Forest (shaded), north-central Arizona. Boundaries and names of 30’ x 60’ quadrangles shown.

Map boundaryPrescott NationalForest boundary

Ash Fork

Paulden

ChinoValley

Prescott

Camp Wood

Humboldt

Jerome

Skull Valley

Yarnell

Flagstaff

Sedona

Camp Verde

Crown King

Mayer

Agua

Fria

River

VerdeRiver

Verde River

Big Chino Valley

Little Chino Valley

Verde Rivervalley

BradshawM

tsBlack Hills

Santa Maria Mts

Will

iam

son

Valle

y

Weaver

Mts

0 10 KILOMETERS

Perkinsville

113°

35°

112°

34°30'

89

89A

69

89

93

17

89A

17

Juniper Mts Big Black Mesa

40 40

Kirkland

Mt. Hope

Picacho Butte

0 6 MILES

Valentine Williams Flagstaff

Bagdad Prescott Sedona

Bradshaw Mountains Payson

Cottonwood

Dugas

Cobble-toboulder-sizeclastsderivedfromtheeastincluderocktypesexposedinBrad-shawMountains,especiallyEarlyProterozoicgabbro,metavolcanicrocks,andgraniticrocks.UnconformableonunderlyingMilkCreekFormation(unitTmc)awayfrombasinmargin.UpperpartofMilkCreekFormation,asusedbyAndersonandBlacet(1972a),isincludedinthisunitbecauseofeasternprovenanceandcontrastingrocktypecomparedtounderlying,fine-grainednatureoflacustrineMilkCreekFormationasoriginallydefined(Hook,1956).Thickness10–240m

Younger volcanic and sedimentary rocks (Pliocene and Miocene)—Alkalibasaltandbasaltflowsandinterbeddedconglomeraticsedimentaryrocks.Incentralpartofmaparea,flowswerederivedfromthenorth,alongtheMogollonRim.Flowsandsedimen-taryrocksfillcanyonscutthroughtheancestralMogollonRim.Innortheasternpartofmaparea,flowswerederivedfromthenortheast,predominantlytheMormonMoun-tainvolcanicfield(NealeyandSheridan,1989;Weirandothers,1989),andincludetheso-called“ramp”basaltsthatflowedintotheancestralVerdeRivervalley.Inthenorthwest,flowswerederivedfromtheJuniperMountains(Goffandothers,1983),andflowedintotheancestralBigChinoValley.Sedimentaryrocks,inaggregate,predomi-nateoverflows.Individualflows10–20mthick.Aggregatethicknessofflowshighlyvariable,about40–50m.Sedimentaryrocksrangegreatlyinthickness,becausetheyweredepositedinchannelscutintounderlyingbedrock.Channeldepositsasthickas60marenotedinplaces.IncludesPerkinsvilleFormation.Ageabout4–7Ma(McKeeandAnderson,1971;Goffandothers,1983)

Taby Alkali basalt—Alkalibasaltflowsandminorcindercones.IncludesflowsinVerdeandPerkinsvilleFormations.Includesonlythoserocksthatareproventobealkalic.Assuch,percentageofoutcropdefinedasalkalibasalt,versusbasalt,isprobablyunderestimated.Compositionrangesfrompicriticbasalttoalkalibasalttotrachybasalt,andincludessomelatiticbasalt(geochemistrydataavailableathttp://pubs.usgs.gov/sim/2996).

AlongnorthernextensionofGrindstoneCanyonfault,northofmaparea,nearlyallanalyzedflowsarealkalic(fig.2A),averagetoverypotassic(fig.2C),andaveragetoveryFerich(fig.2D).

InJuniperMountainsinnorthwesternpartofmaparea,alkalicflows(fig.3A)areaverageintheirK/Naratio(fig.3C)andrangefromveryMgrichtoFerich(fig.3D).

NearPaulden,alkalicrocksarerepresentedbyonlyoneanalysisofthelowerflowdownstreamfromSullivanLakedamandoneanalysisoftheflownearDrake(fig.4A);otheranalysesoftheseflowsarenotalkalic.

AlkalicflowsinVerdeFormationnearmouthofSycamoreCreekrangeincom-positionfrombasanitetolatiticbasalt(fig.5A),areaveragetoverypotassic(fig.5C),andareaveragetoveryMgrich(fig.5D).SomeflowsinMundsParkandSchneblyHillarea,justeastofmaparea,arealkalic,butmorearenotalkalic(fig.5C).

IncludesflowsinPerkinsvilleFormation,whichcropsoutbetweenPauldenandVerdeRivervalley.AgeofflowinVerdeFormationnearmouthofSycamoreCanyonis4.6Ma.AgeofflowsinVerdeFormationnearInterstate17about5.7–6.4Ma(Don-chin,1983).AgeofflowsinPauldenareaabout4.6–6.3Ma

Tby Basalt—Basaltflowsandminorcindercones.Includesallcompositionsofbasaltnotproventobealkalic.IncludesflowsinVerdeandPerkinsvilleFormations.Assuch,percentageofoutcropdefinedasbasalt,versusalkalibasalt,isprobablyoverestimated.Compositionispredominantlybasalt,butincludesminorandesite.

InJuniperMountainsinnorthwesternpartofmaparea,flowsrangeincomposi-tionfrombasalttoandesiticbasalt(fig.3A),aresodictoaverageinK/Naratio(fig.3C),andareveryMgrich(fig.3D).

NearPauldenallflowsarebasaltthatisaveragetopotassic(fig.4C)andMgrichtoaverage(fig.4D).

FlowsanddikesinVerdeFormation,alongandnorthofInterstate17,appeartodefinetwopopulations:basaltthatisaveragetopotassic(fig.5C)andveryMgrichtoFerich(fig.5D);andandesitethatisverysodictosodic(fig.5C)andveryMgrichtoaverage(fig.5D).

Description of Map Units �

Figure 2. Major-element classification diagrams for 4- to 6-Ma volcanic rocks (units Taby and Tby) north of Perkinsville. Data from L.W. Nealey in Baedecker and others (1998). Localities are all north of map area. Geochemistry data available at http://pubs.usgs.gov/sim/2996). A, R1R2 major-element classification diagram (De la Roche and others, 1980). Picritic, ultramafic composition; Ban, basinite; Alk Bas, alkali basalt; Bas, basalt; Th, tholeiite; Tr Bas, trachybasalt; Lat Bas, lati-basalt; And-Bas, andesitic basalt; Tr And, trachyandes-ite; Lat, latite; Lat And, lati-andesite; And, andesite; Q Tr, quartz trachyte; QL, quartz latite; Dac, dacite; Rhy, rhyolite; R Dac, rhyodacite. Fields of alkalinity from Fridrich and others (1998). B, Alumina saturation diagram (SiO2 versus A/CNK). A, molar Al2O3; C, molar CaO; N, molar Na2O; K, molar K2O. Field of unal-tered igneous rocks from DeWitt and others (2002). C, Alkali classification diagram (K2O/(K2O + Na2O) versus SiO2). Field boundaries from Fridrich and others (1998). D, Iron enrichment classification diagram (FeO + 0.89*Fe2O3)/(FeO + 0.89*Fe2O3 + MgO) versus SiO2. Field boundaries from DeWitt and others (2002).

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)

(FeO + 0.89Fe2O3)/(FeO + 0.89Fe2O3+ MgO)

D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK

Field of unalteredigneous rocks B

SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-CalcicAlkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Summit MountainSouth of Summit MountainKunds KnollNear Bear Canyon roadBuzzard KnollAlong Grindstone Canyon fault

EXPLANATION


60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

Northwest corner of map

Squaw Peak, west of map Henry Brown Mountain, west of map East Juniper Mountains Flows around Picacho Butte, northwest of map

EXPLANATION

Figure 3. Major-element classification diagrams for 4- to 6-Ma volcanic rocks (units Taby, Tby, and Tay) in northwest corner of map area. Data from Arney and others (1985). Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

Description of Map Units 5

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Flows near Paulden

Top flow Lower flow Cinder pit Drake flow Hell Point flow Black Mesa flow Del Rio drillhole flow Magnetite-rich flow

EXPLANATION

Figure 4. Major-element classification diagrams for 4- to 6-Ma volcanic rocks (units Taby and Tby) near Paulden. Data from this study, McKee and Anderson (1971), and Wittke and others (1989). Rock abbreviations and field boundaries defined in figure 2.


60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

EXPLANATION

In Verde River valley

In Verde Formation Near Interstate 17 Munds Park, Schnebly Hill Stoneman Lake Lower Verde Formation, southeast of Squaw Peak

Figure 5. Major-element classification diagrams for 4- to 6-Ma volcanic rocks (units Taby and Tby) in Verde River valley and east of Sedona. Data from McKee and Anderson (1971), and L.D. Nealey, B. Houser, M. Chaffee, and G.E. Ulrich in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2.


ManyoftheflowsinMundsParkandonSchneblyHill,eastofmaparea,arenormalbasalt(fig.5).

Distinguishedfromolderflowsbyclastcompositionofinterbeddedconglomer-aticrocks.IncludesflowsinPerkinsvilleFormation,whichcropsoutbetweenPauldenandVerdeRivervalley.AgeofflowsineasternJuniperMountainsabout5.5–6.2Ma

Tcy Cinders and cinder cones—Cindersinbedsanderosionalremnantsofcones.MappedonlynorthandnortheastofPaulden.Compositionpresumedtobebasalt.ConenorthofPauldencouldbesourceofflowsnearSullivanLake

Tay Andesite—AndesiteflowineasternJuniperMountainsandfarwesternBigChinoValleythathasdistinctivecurvingcolumnarjoints.Chemicallyiscalc-alkalic(fig.3A),meta-luminous(fig.3B),averageinK/Naratio(fig.3C),andveryMgrich(fig.3D)

Tdy Dacite—Daciteandrhyodacitedomesandflows.InfarsouthernVerdeRivervalleyincludesflowdomeatbaseofVerdeFormation(Wolfe,1983)thatisarhyodacitethatisalkali-calcic(fig.5A),mildlyperaluminous(fig.5B),verysodic(fig.5C),andveryMgrich(fig.5D).Ageabout7.4Ma(McKeeandElston,1980)

Tbsy Basalt and sedimentary rocks—Youngerbasaltflowsandinterbeddedconglomerateandmixedsedimentaryrocks.Flowspredominateoversedimentaryrocks.Basalt-cobbleconglomerateismostabundantsedimentaryrock.IncludespartsofPerkinsvilleForma-tion,whichcropsoutbetweenPauldenandVerdeRivervalley

Tsvy Sedimentary and volcanic rocks—Mixedsedimentaryrocksandinterbeddedvolcanicflowsofmafictointermediatecomposition.Sedimentaryrockspredominateoverflows.Sedimentaryrocksincludebasalt-cobbleconglomerateandmixedtuffaceousrocks

Tsy Sedimentary rocks—Mixedsedimentaryrocks.Includessiltstone,sandstone,andminorconglomeratewestofWilliamsonValleyWashandinfarsouthwesternBigChinoVal-ley.DerivedfromSantaMariaMountains,tothesouthwest.Infarsouthernexposurescontainsthinbasaltflows.ThickensgreatlyintoWilliamsonValleyWashnearTuckerwheredrillingandgravitydatasuggestthicknessasmuchas800m(Langenheimandothers,2002)

Tgy Gravel—CoarsegravelandconglomerateeastofSantaMariaMountains;thickness5–50m.Isolateddepositsinfarsoutheastcornerofmap;thickness2–20m

Older volcanic and sedimentary rocks (Miocene)—Alkalibasalt,basalt,andesiticbasalt,andlati-andesiteflows;dacitetorhyodaciteflowsanddomes;andinterbeddedtuffa-ceoussedimentaryrocks.Sedimentaryrocksderived,primarily,fromthesouthandsouthwest.IncludesThirteenmilevolcanicrocksinsoutheasternpartofmapareaandrocksyoungerthanHickeyFormation(10–15Ma)andolderthanyoungerbasalt(4–7Ma)throughoutmaparea.Flowspredominateoversedimentaryrocks.Individualflows10–25mthick.Aggregatethicknessofflowsasmuchas100m.Ageabout7–10Ma(McKeeandElston,1980)

Tabo Alkali basalt—AlkalibasaltflowsnearbaseandtopofThirteenmilevolcanicrocksinHackberryMountainarea,andinMountHopearea,westofmaparea.Includesonlythoserocksthatareproventobealkalibasalt.Assuch,percentageofoutcropdefinedasalkalibasalt,versusbasalt,isprobablyunderestimated.

AlkalibasaltandpicriticrocksnearbaseofThirteenmilevolcanics(fig.6A)arepotassictoverypotassic(fig.6C)andrangefromveryMgrichtoveryFerich(fig.6D).

TrachybasaltinMt.Hopearea(fig.7A)isaveragetoverypotassic(fig.7C)andaveragetoFerich(fig.7D).

OnesillinMartinFormation,alongChasmCreek,westofVerdeRiver,isanalkalibasalt(fig.6A)thatismoderatelyperaluminous(fig.6B),verysodictoaverage(fig.6C),andaverageinitsFe/Mgratio(fig.6D).

Anundated,distinctive,magnetite-richfloweastofPauldenisalkalic(fig.8A),verypotassic(fig.8C),andaverageinFe/Mgratio(fig.8D).FlowispresumedtobelongtotheoldervolcanicrocksbecauseofitsintermediatetopographicelevationbetweenflowsofHickeyFormationandflowsofyoungervolcanicrocks,butcouldbeofHickeyage


Description of Map Units �

40

50

SiO

2 (w

t. p

erce

nt)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

60

50

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SiO

2 (w

t. p

erce

nt)


D

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K2O/K2O + Na2O

C

0.4

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40 50 60

A/C

NK


SiO2 (wt. percent)

EXPLANATION

Hackberry Mountain area

Tuff of Towel Creek, units 1-7Tuff of Towel Creek Tuff at Hackberry MtnTuff at Chalk Mtn

Thirteenmile basalt, units 10-15Andesite of Cimarron Hills, units 1-3BrecciaDacite of Hackberry MountainRhyoliteThirteenmile basalt, youngest

Dacite of Sally May, intrusive

Verde Rim area

Interstate 17 andesiteArnold Mesa basal flowsArnold Mesa middle flowsChasm Creek sill

Figure 6. Major-element classification diagrams for 8- to 10-Ma volcanic rocks (units Tabo, Tbo, Tao, Tdo, Trdo, and Tto) at Hackberry Mountain and along Interstate 17, west of Verde River valley. Data from this study, Scott (1974), and Lewis (1983). Rock abbreviations and field boundaries defined in figure 2.

10 Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Arizona

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


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0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

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NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

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2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Mt. Hope area

Basalts Andesites Rhyolite at Mt. Hope

EXPLANATION

Figure 7. Major-element classification diagrams for 8- to 10-Ma volcanic rocks (unit Tbo and other more felsic rocks) at Mt. Hope, west of map area. Data from Nealey and others (1986), Simmons (1986), Simmons and Ward (1992), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2.


2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

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1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

Flows near Paulden

Del Rio drillhole King Canyon flow

West of Prescott

Near KirklandWest of Martin MountainMartin Mountain coreNorthwest of Iron SpringsSmith Mountain

EXPLANATION

Figure 8. Major-element classification diagrams for 8- to 10-Ma volcanic rocks (units Tabo and Tbo) and Tgbd west and northwest of Prescott, and from near Paulden. Data from this study and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2.

Tbo Basalt—Basaltflows,cindercones,andminordikes.Includesallcompositionsofbasaltnotproventobealkalibasalt.Assuch,percentageofoutcropdefinedasbasalt,versusalkalibasalt,isprobablyoverestimated.

BasaltinlowerpartofThirteenmilevolcanicrocks(fig.6A)hasanaverageK/Naratio(fig.6C)andisveryMgrichtoMgrich(fig.6D).

UndatedflowswestofKirklandandwestofMartinMountainrangeincomposi-tionfrombasalttoandesiticbasalt(fig.8A),aresodictoaverageinK/Naratio(fig.8C),andareveryMgrichtoveryFerich(fig.8D).

BasalpartofThirteenmilevolcanicrocksmayincludesomebasaltthatisequivalenttothatinHickeyFormation

Tco Cinders and cinder cones—Cindersinbedsanderosionalremnantsofcones.Presumedtobebasalticincomposition.ExposedpredominantlyinHackberryMountainarea

Tao Andesite—Minor,butdistinctive,andesiteinsouthernBlackHills,oneithersideofInterstate17,includesdistinctivegray,platy-weatheringflowthatispresumedtobetime-correlativeofyoungesttufferuptedfromHackberryvolcaniccenter(Lewis,1983).Chemically,rockisalati-andesitetoandesite(fig.6A)thatisverysodic(fig.6C)andhasanaverageFe/Mgratio(fig.6D).AndesiteofsimilarcompositionisfoundinMor-monMountainvolcanicfield,eastofmaparea(Wierandothers,1989).

OtherrocksreferredtoasandesiteinMt.Hopearearangeincompositionfrombasalttoandesite,andaremostlyandesiticbasalt(fig.7A)thatisaveragetopotassic(fig.7C)andveryMgrichtoMgrich(fig.7D)

Tdo Dacite—Daciteflowsanddomes.InsouthernVerdeRivervalleyincludesdaciteatHack-berryMountainwithinThirteenmilevolcanicrocksnearHackberryMountain(Lewis,1983;Scott,1974).Muchdaciteisactuallyrhyodacite(fig.6A)thatismoderatelyper-aluminous(fig.6B),verysodictosodic(fig.6C),andveryMgrich(fig.6D).AthicksectionofdacitetuffatGranitePeakinfarsoutheasternpartofmapareaisundated,butassumedtobecorrelativewithHackberryMountaindacite

Trdo Rhyodacite—Daciteflowsanddomes.InsouthernVerdeRivervalleyincludesdaciteatSallyMaywithinThirteenmilevolcanicrocksnearHackberryMountain(Lewis,1983;Scott,1974).Rhyodaciteismoderatelyperaluminous(fig.6B),sodic(fig.6C),andMgrichtoFerich(fig.6D)

Tto Tuff—Rhyodacitetoandesitictuffandinterbeddedashbeds.InsouthernVerdeRivervalleyincludestuffatTowelCreekwithinThirteenmilevolcanicrocksnearHackberryMountain(Lewis,1983)northofDugas.InHackberryMountainarea,oldestunitsaremostfelsic;youngestunitsaremostmafic.Eruptionoftuffprobablysignalsemptyingofmagmachamber,withmostmaficcomponentsoftuffequivalentincompositiontoandesiteflows(unitTao).Rangesincompositionfromrhyodacitetoandesite(fig.6A)andismetaluminoustomoderatelyperaluminous(fig.6B),sodictoaverageinK/Naratio(fig.6C),andveryMgrichtoMgrich(fig.6D).Otherbedsoftuffinoldervolca-nicsarepresumedtoberelatedtotheseashbeds.TuffexposedsouthofSkullValleyismorerhyoliticincompositionandcouldbe,inpart,older,andrelatedto15-Mavolcanism

Tmo Volcanic rocks—Mixedvolcanicflowsofmafictointermediatecomposition.ExposedeastofStricklandWash,inwesternpartofmaparea,andsouthofJohnsonFlat,infarsouthernpartofmaparea

Tbso Basalt flows and interbedded sedimentary rocks—Basaltflowsandinterbeddedbasalt-cobbleconglomeratenearJuniperMountains

Tso Sedimentary rocks—Multi-clastconglomeratecontainingPaleozoicandEarlyProtero-zoiccobblesandboulders.Derivedpredominantlyfromthesouthwest.ThicksequenceofclasticrocksexposedsouthofCedarMesaandwestofSycamoreMesa,infarsouth-westernpartofmaparea,fillspaleo-channelalongSycamoreCreek.Imbricateclastsinthisareasuggestsouthwesttransport.Channelatleast8kmwideatsouthwestedgeofmap.Channeldepositsthickentothesouthwest

Volcanic and sedimentary rocks of undetermined age (Miocene? and Oligocene?)—Basalt,andesite,dacite,andinterbeddedsedimentaryrocks.Chemistryundetermined.

1� Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Arizona


Probably equivalent to older volcanic and sedimentary rocks or, in part, to rocks ofHickey Formation

Tbu Basalt (Miocene?)—Basalt and andesite flows. Exposed north of Limestone Peak inwestern Big Chino Valley, southeast of Little Purcell Canyon in far northwestern part ofmap area, and at Malpais Hill at far south edge of map, where rocks may be of Hickeyage

Tgbd Gabbro-diorite (Miocene?)—Fine-grained, equigranular, irregularly shaped intrusivebody that cuts dacitic shield volcano at Martin Mountain. Chemically is alkali-calcic(fig. 8A), metaluminous, and Mg rich, and has average K/Na ratio. Composition similarto that of basalt flows (unit Tbo) north and west of Martin Mountain

Tbd Basalt dikes (Pliocene and Miocene)—Predominantly northwest striking, high-angledikes that are feeders to younger basalts (4–6 Ma), older basalts (7–10 Ma), and basaltsin Hickey Formation (10–15 Ma). Exposed throughout map area. Individual dikes1–20 m thick and 50–800 m long

Tmu Volcanic rocks (Miocene? and Oligocene?)—Mixed basalt, andesite, and possible lati-andesite flows. Exposed along Dillon Wash in southwestern Sullivan Buttes where darkandesite(?) flows may be present, southwest of Goat Peak in Santa Maria Mountains,and northwest of Skull Valley where dacite from Martin Mountain may be interbeddedwith rocks previously described

Tsb Sedimentary rocks and basalt (Miocene?)—Interbedded basalt-cobble conglomer-ate, clastic sedimentary rocks, and basalt flows at Turret Peak and Rugged Mesa in farsoutheast corner of map

Tsv Sedimentary and volcanic rocks (Miocene?)—Mixed sequence of andesite to basaltflows and clastic sedimentary rocks. Exposed in western part of map area, east of EaglePeak and east of Tailholt Mesa. Thickness at least 100 m. Sedimentary rocks probablythicken toward northeast, into basin underlying southern Williamson Valley (Langen-heim and others, 2002)

Tsu Sedimentary rocks (Miocene? and Oligocene?)—Conglomerate and sandstone contain-ing Paleozoic and Precambrian cobbles derived from the southwest. Exposed north ofBig Chino Wash, in far northwestern part of map area. Thickness at least 20 m

Hickey Formation (Miocene)—Basalt flows and minor, interbedded sedimentary rocks.Interbedded sedimentary rocks derived from Basin and Range province, to the south-west. Flows predominate over sedimentary rocks. Thickness of individual flows 10–25m. Thickness of aggregate flows as much as 120 m. Age about 10–15 Ma (McKee andAnderson, 1971; Wittke and others, 1989)

Thab Alkali basalt—Alkali basalt flows, cinder cones, and minor dikes. Includes only thoserocks that are proven to be alkali basalt. As such, percentage of outcrop defined asalkali basalt, versus basalt, is probably underestimated.

In Prescott area, trachyandesite at Thumb Butte (fig. 9A) is alkalic and potassicto very potassic (fig. 9C) and has an average Fe/Mg ratio (fig. 9D). Near Mayer, mostflows are alkalic, potassic to very potassic (fig. 9C), and very Mg rich to average in Fe/Mg ratio (fig. 9D). Flows north of Prescott are predominantly alkalic (fig. 9A), potassicto very potassic (fig. 9C), and very Mg rich (fig. 9D).

Along crest of Black Hills, from north of Woodchute Mountain to Cherry, alkalibasalt underlies calc-alkalic to alkali-calcic basalt (Wittke and others, 1989). Theserocks range in composition from basinite to alkali basalt (fig. 10A) and are average tovery potassic (fig. 10C) and very Mg rich to average (fig. 10D). Map compilation didnot allow differentiating the alkalic rocks from the overlying basalts; therefore all theoutcrop of Hickey Formation from Woodchute Mountain to Cherry is shown as basalt(unit Thb).

Flows north of Woodchute Mountain, from near First View on the east to St.Matthews Mountain on the west, range in composition from trachybasalt to basinite toalkali basalt (fig. 10A) and are potassic to very potassic (fig. 10C) and very Mg rich toaverage (fig. 10D).

Flows and plugs at Casner Butte, just east of map area, are strongly silica-under-saturated and range in composition from phono-tephrite to ankaritrite to alkali basalt

60

50

400.4 0.5 0.6 0.7 0.8 0.9

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t. p

erce

nt)


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0 0.1 0.2 0.3 0.440

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K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

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Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Prescott-Mayer area

Thumb ButtePrescottBig Bug MesaMayerWest of Chino ValleyBlack HillCordes

EXPLANATION

Figure 9. Major-element classification diagrams for 10- to 15-Ma volcanic rocks of Hickey Formation (units Thb, Thab, and Tha) near Prescott. Data from this study, McKee and Anderson (1971), Duncan and Spencer (1993), and Nichols Boyd (2001). Rock abbreviations and field boundaries defined in figure 2. Blue triangles on A are correctly plotted to left of outline.


Description of Map Units 1�

Figure 10. Major-element classification diagrams for 10- to 15-Ma volcanic rocks of Hickey Formation (units Thab, Thb, and Tha) in the Black Hills and northeast of Cordes Junction. Data from this study, McKee and Anderson (1971), Wittke and others (1989), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2.

60

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2 (w

t. p

erce

nt)


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0 0.1 0.2 0.3 0.440

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K2O/K2O + Na2O

SiO

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t. p

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nt)

C

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SiO2 (wt. percent)

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1000

1500

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Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Black Hills

Central Mingus MountainAlong Verde faultNorth of Woodchute MountainEstler volcanic field

EXPLANATION

topicriticbasalt(fig.11A)andareverypotassic(fig.11C)andveryMgrichtoveryFerich(fig.11D).FlowsattopofLeeandMundsMountains,eastofSedona,althoughnotdated,havethechemistryofotherbasalflowsintheHickeyFormationbybeingstronglysilica-undersaturatedbasaniteandalkalibasalt(fig.11A)thatareverypotassic(fig.11C)andMgrich(fig.11D).

Distinguishedfromyoungerflows(unitsTabyandTby)bypercentageandprovenanceofinterflowsedimentaryrocks.Somesilica-undersaturatedalkalibasaltintheHickeyisdifficulttodistinguishfromflowsinupperpartofThirteenmilevolcanicrocks

Thb Basalt—Basaltflows,cindercones,andminordikes.Includesallcompositionsofbasaltnotproventobealkalibasalt.Assuch,percentageofoutcropdefinedasbasalt,versusalkalibasalt,isprobablyoverestimated.Rangesincompositionfromandesiticbasalttobasalt.

SoutheastofPrescott,andeastofGlassfordHill,flowsarebasalttoandesiticbasalt(fig.9A)thataresodictopotassic(fig.9C)andveryMgrichtoMgrich(fig.9D).

AtBigBugMesaandLittleMesa,flowsarebasalttolatiticbasalt(fig.9A)thatareaverageinK/Naratio(fig.9C)andMgrichtoaverage(fig.9D).

CappingflowsatcrestofBlackHills,fromWoodchuteMountaintoCherry,areandesiticbasalt(fig.10A)thatisverysodic(fig.10C)andveryMgrichtoaverage(fig.10D).

TheEstlervolcanicfield,nearEstlerPeak,northeastofCordesJunction,con-tainsbasaltandminorandesiticbasalt(fig.10A)thatissodictoaverage(fig.10C)andmostlyaveragetoFerich(fig.10D).

OnlyoneanalysisisavailableforflowsonflankofHouseMountain,inVerdeRivervalley.TheoneandesiticbasaltissimilartothoseoncrestofBlackHills(fig.11A)andisaverageinK/Naratio(fig.11C)andFerich(fig.11D).

AllexceptoneflowinHickeyFormationsouthwestofHackberryMountainarebasalttoandesiticbasalt(fig.12A)thatareaveragetoverypotassic(fig.12C)andveryMgrichtoveryFerich(fig.12D).

Distinguishedwithdifficultyfrombasaltinoldervolcanics(unitTbo)andfrombasaltinyoungervolcanics(unitTby).Interflowsedimentstypicallycontainbasementclastsderivedfromthesouthwestandlackbasaltclasts

Thc Cinder cones and basalt dikes—IncludesconstructionaledificesatGlassfordHill,northeastofPrescott;smallerconesinEstlervolcanicfield,southeastofInterstate17;andcoreofHouseMountainvolcano.AtHouseMountain,silica-undersaturatedrocksareincludedwithcindersanddikesandhaveagreatrangeincomposition,fromphono-tephrite,tephrite,trachybasalt,alkalibasalt,ankaritrite,picriticbasalt,tominortrachyte(fig.13A).Maficrocksaremostlypotassictoverypotassic(fig.13C),andrangefromveryMgrichtoveryFerich(fig.13D)

Tha Trachyandesite—FlowsatbaseofHickeyFormation,westofPrescottatThumbButte;westandsouthoftownofChinoValley;alongVerdefaultinJeromearea;andsouthofMayer.

AtThumbButte,trachyandesite(fig.9A)ispotassictoverypotassic(fig.9C)andaverageinFe/Mgratio(fig.9D).AtPrescott,oneflowisalatiticbasalt(fig.9A)thatisverypotassic(fig.9C)andveryMgrich(fig.9D).FlowswestandsoutheastoftownofChinoValleyaretrachybasalt(fig.9A)thatisaverageinitsK/Naratio(fig.9C)andMgrich(fig.9D).

AlongVerdefault,basalflowsrangeincompositionfromtrachybasaltandlati-basalttobasiniteandalkalibasalt(fig.10A).TheserockshaveK/NaandFe/MgratiossimilartothoseofbasalalkalibasaltsontopofBlackHills.

SouthofMayer,anerodedconeistrachyandesite(fig.9A)thatissodic(fig.9C)andaverageinFe/Mgratio(fig.9D).AK-Ardateonhornblendeofabout19MahasbeencitedasevidencethattheconemayberelatedtotheSullivanButtesvolcanicfield.TrachyandesitecompositionsuggeststhatconemaybeageofbasaltofHickeyForma-tioninarea.

AgeatThumbButteabout15Ma(NicholsBoyd,2001)


Figure 11. Major-element classification diagrams for 10- to 15-Ma volcanic rocks of Hickey Formation (units Thb, Thab, and Tha) east and southeast of Sedona. Data from G.E. Ulrich in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2. Points in A that are left of the outline are correctly plotted.

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)

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Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

2

Lee, Munds Mountain flowsCasner, Maverick Butte flows, plugsCasner Butte

Undersaturated rocks Basalt

EXPLANATION


Figure 12. Major-element classification diagrams for 10- to 15-Ma volcanic rocks of Hickey Formation (units Thb and Thab) in Hackberry Mountain and Arnold Mesa areas. Data from Lewis (1983) and Wolfe (1983). Rock abbreviations and field boundaries defined in figure 2.

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R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Arnold Mesa area Basal flows Dike in Paleozoic

Hackberry Mountain area Flows, units 2-12

EXPLANATION


Figure 13. Major-element classification diagrams for 10- to 15-Ma volcanic rocks of Hickey Formation (units Thb, Thab, and Thc) near House Mountain. Data from Wittke and Holm (1986), L.D. Nealey in Baedecker and others (1998), and Holm and others (1998). Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated. Points in A that are left of the outline are correctly plotted.

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R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

House Mtn

Undersaturated rocks Dikes and flows Evolved rocks Flows

EXPLANATION


Tht Tuff—Rhyolitetuffandinterbeddedashbeds.MappedonlynearChasmCreek,south-westofVerdeRiver.Thickness1–10m

Thbs Basalt and sedimentary rocks—Interbeddedbasaltandalkalibasaltflowsandsedimen-taryrocks.Flowspredominateoversedimentaryrocks

Thsb Sedimentary rocks and basalt—Interbeddedsedimentaryrocksandbasaltandalkalibasaltflows.Sedimentaryrockspredominateoverflows

Ths Sedimentary rocks—CobbleconglomerateatbaseofHickeyFormation.Minorinterbed-dedsedimentaryunitsnotedhigherinformation,betweenbasaltflows.Localfresh-waterlimestoneandtravertinenorthofMayerandsoutheastofCordesareincludedwithinunitThs.ClastspredominantlyPaleozoiclimestoneandsandstone,andEarlyProterozoiccrystallinerocksderivedfromthesouthwest.Thicknesshighlyvariable,from10to40m,asmostdepositsdefinechannelscutintoPaleozoicorEarlyProtero-zoicrocks.ThickestsectionalongVerdefault,eastofCherry,whereapproximately100moffluvialdepositsdefineanortheast-flowingriversystem

Tbx Breccia (Miocene)—Angularrhyoliticbrecciaandhydrothermal(?)explosionbrecciaalongfaultsandfractures,andinlargerbodies.MostabundantfromsouthernpartofCopperBasintoLittleCopperCreek,alongU.S.Highway89A,southwestofPrescott(Light,1975)

Tr Rhyolite (Miocene)—RhyolitedikesandminorflowsinCopperBasinandsouthofSkullValley.Ageabout15Ma(Christman,1978).BrecciateddikesandbrecciabodiesalongCopperCreek,eastofWilhoit(Hennessy,1981).ThreesmallplugssouthofPineMountain,infarsoutheastcornerofmaparea,couldbeyounger,about7–10Ma.OneremnantofdomewestofBearMountaininfarnorthwestcornerofmaparea

Milk Creek Formation (Miocene)—Limestone,siltstone,dacitedomes,andminorlati-andesiteandbasaltflows.Clasticsedimentaryrocksderivedfromthesouthwest.Ageofdacite15Ma(McKeeandAnderson,1971).Thicknessofsedimentaryrocks300mormore,asdeterminedfromexploratorydrillholeseastofBlackMountain.FossilageofupperpartofsedimentaryrocksisClarendonian(Hook,1956),orupperMiocene,about5–11Ma

Tmcd Dacite—Dacitedomesandflowsinterbedded(?)withinMilkCreekFormationinWalnutGrovearea.LargestdomeatBlackMountainandsmallerflowstothewestaredacite(fig.14A)thatismetaluminoustomoderatelyperaluminous(fig.14B),sodictoaver-age(fig.14C),andveryMgrich(fig.14D).Ageofdacite15.0–15.2Ma(McKeeandAnderson,1971)

Tmcl Lati-andesite—FlownearBlindIndianCreekthatisalati-andesite(fig.14A),potassic(fig.14C),andaverageinFe/Mg(fig.14D)

Tmc Sedimentary rocks—Fine-grainedclasticrocksandminorlimestoneandclaystonedepositedinfluvialandlacustrinesetting.Rocktypesincludefine-grainedandslightlyinduratedsandstone,mudstone,andlesserdiatomite,siltylimestone,paleosols,andgravel.Clastsincludegneissicgranite,granitic,andmetavolcanicrocks.Interlay-eredwithminorbasalticflows.Stratadipgentlyeastexceptadjacenttofaultsandinsynclines.Depositsfillseveraltiltedhalf-grabens.East-dippingMilkCreekFormationisjuxtaposed,alongitsoutcroplength,againstEarlyProterozoicgraniticandmetavol-canicrockstotheeastbyalargelycovered,normalfault.InMcAllisterRange,faultsrelatedtothisbasin-boundingfaultcontainextensivegougealteredtoepidote.Locally,somefaultsinMcAllisterRangeareintrudedbydikesofunknownage

Lati-andesite of Sullivan Buttes and Santa Maria Mountains (Miocene? and Oligo-cene)—Flows,domes,agglomeratebodies,andcinderconesofandesiticbasalt,latite,lati-andesite,anddaciteexposedatSullivanButtes,SantaMariaMountains,JuniperMountains,andpossiblysouthofWilhoit.Inplaces,containsabundantmafictoultra-maficxenolithsrepresentativeoflowercontinentalcrust(ArculusandSmith,1979;Smithandothers,1994).Anareallylargegravityhighextendingsouth-southwestfromtownofChinoValleymayindicatealargebodyofmafictoultramaficrocksofEarlyProterozoicageintheuppercrust(Langenheimandothers,2002,fig.8).CharacteristicchemistryofallrocksistheirK-andMg-richnature.Intrusivecentersarereverselymagnetized,creatingaeromagneticlowsovermanybodies(Langenheimandothers,

�0 Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Arizona

Description of Map Units �1

Figure 14. Major-element classification diagrams for 10- to 15-Ma volcanic rocks in Milk Creek Formation (units Tmcd and Tmcl) near Wagoner and from a latite body south of Mayer. Data from this study and McKee and Anderson (1971). Rock abbreviations and field boundaries defined in figure 2.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

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0.6

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40 50 60

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NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

Milk Creek flows

EXPLANATION

2002).AgeinSullivanButtesareaabout21–27Ma.AgeinJuniperMountainsabout22–34Ma.AgeundeterminedinSantaMariaMountainsandelsewhere

Tlau Upper unit—Gentlydippingflowsoflati-andesite,andesite,andandesiticbasalt(fig.15A).MostabundantinSullivanButtesvolcanicfieldneartownofChinoValley.Flowsareverypotassic(fig.15B)andveryMgrich(fig.15D).Thicknessofindividualflows5–15m.Ageundetermined

Tlal Lower unit—Flows,domes,breccia,cindercones,andintrusivecentersoflati-andesite,andesite,anddacitecomposition,andlesseramountsofandesiticbasaltandbasalt(figs.15A,16A).MostabundantinSullivanButtesvolcanicfieldneartownofChinoVal-ley.Allrocksareaveragetoverypotassic(figs.15C,16C)andMgrichtoveryMgrich(figs.15D,16D).Thicknessofdomesandcompoundflowsdoesnotexceed80m

Tla Undivided lati-andesite—ErodedvolcanicconeinnorthernJuniperMountainsandlargedomeedificeatDennyMountain,inSantaMariaMountains(Ash,1997).ConeinJuniperMountainsrangesincompositionfromlatitetolati-andesite(fig.17A)andispotassictoverypotassic(fig.17C)andMgrichtoveryMgrich(fig.17D).FlowsanddomesatDennyMountainarelargelylati-andesite(fig.17A)thatisverypotassic(fig.17C)andveryMgrich(fig.17D).AgeofconeinJuniperMountainsabout24–36Ma

Ta Andesite—FlowsandflowdomesexposedatBearMountain,innorthernSantaMariaMountains,ofandesitetolati-andesite(fig.17A)thatisverypotassic(fig.17C)andveryMgrich(fig.17D).OtherflowspresumedtobeandesiticincompositionarenorthofWalnutCreek,infarwesternpartofBigChinoValley

Td Dacite—DaciteflowsnearHideCreekMountainandnorthtowardIndianPeakinSantaMariaMountains,andalargevolcanicedificeatMartinMountain,southwestofSkullValley.SmallerbodiessouthwestofWilhoitcontainabundantmudflows,andmaybeofdifferentage.FlowsonHideCreekMountainandnearIndianPeakaredacite(fig.17A)thatispotassictoverypotassic(fig.17C)andveryMgrich(fig.17D).BodyatMartinMountainisdacite(fig.17A)thatissodic(fig.17C)andveryMgrich(fig.17D)

Tos Sedimentary rocks (Miocene and Oligocene)—Fluvialconglomerate,sandstone,fresh-waterlimestone,andlocalconglomeraterichinlati-andesiteclasts.Underlieslati-andesite(unitsTlau,Tlal,Tla,Ta,andTd)inSullivanButtesareaandinnorthernSantaMariaMountains,southofWalnutCreekandalongWalnutCreek.ContainsclastsofPaleozoicandEarlyProterozoicrocks.Derivedpredominantlyfromthesouth-west.WidthofcompoundchannelineasternSullivanButtesabout3.5km.Thicknessvariable,asmuchas60m

CENOZOIC AND MESOZOIC INTRUSIVE ROCKS

TKb Breccia pipes (Paleocene and Late Cretaceous)—Mineralizedpipesofhydrothermalbrec-ciaassociatedwithCopperBasinstock(JohnstonandLowell,1961;Christman,1978).ContainclastsofLateCretaceousigneousrocksofvariouscompositionsandtextures.PipestoosmalltobeshowninwesternpartofCrownKingstock(Ball,1983)

TKr Rhyolite dikes (Paleocene and Late Cretaceous)—Fine-grained,porphyriticrhyolitedikescontainingquartzphenocrystsandfewmaficminerals.ExposedfromCrownKingstocktopastsouthernboundaryofmaparea.AbundanceofdikessouthofCrownKing,nearSilverMountain,mayindicatefelsicplutonatdepth.Limiteddatasuggestcalc-alkalicrhyolitecomposition(fig.18A).Hydrothermalalterationofdikescausesthemtobestronglyperaluminous(fig.18B),potassic(fig.18C),andveryFerich(fig.18D)

TKgd Granodiorite and rhyodacite porphyry dikes (Paleocene and Late Cretaceous)—Fine-grainedporphyriticgranodioriteandrhyodacitedikescontainingfeldsparandbiotitephenocrysts.OnestockexposedatPineFlat,westofBradyButte(Spatz,1974).DikesexposedfromCrownKingstocktoPolandJunctionandWalkerstocks,andnearCop-perBasinstock.Unaltereddikesarealkali-calcictocalc-alkalicdacite(fig.18A)thatismetaluminoustomildlyperaluminous(fig.18B),verysodictosodic(fig.18C),andaverageinFe/Mgratio(fig.18D).Hydrothermallyaltereddikesareenrichedinalkalielementsandarealkali-calcicrhyolitetoalkalirhyolite(fig.18A)thatisstronglyper-aluminous(fig.18B),potassictoverypotassic(fig.18C),andveryFerich(fig.18D).

�� Geologic Map of the Prescott National Forest and the Headwaters of the Verde River, Arizona

Figure 15. Major-element classification diagrams for 21- to 27-Ma volcanic rocks in Sullivan Buttes volcanic field (units Tlal, Tlau, and Tla) near town of Chino Valley. Data from Tyner (1984). Bt, biotite; pyx, pyroxene. Rock abbreviations and field boundaries defined in figure 2. Black arrow indicates point lies outside of plot, in direction indicated.

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

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40 50 60

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NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

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Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2

EXPLANATION

Sullivan Buttes

Upper flowsMafic intrusiveBt-pyx porphyry flows, brecciaAmphibole porphyry flowsBasaltic flows, cones

Description of Map Units ��

Figure 16. Major-element classification diagrams for 21- to 27-Ma volcanic rocks in Sullivan Buttes volcanic field (units Tlal, Tlau, and Tla) near town of Chino Valley. Data from Ward (1993) and Duncan and Spencer (1993). Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

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40 50 60

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NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

Sullivan Buttes

Pyroxene porphyry flowsBiotite porphyry flows, domesAmphibole porphyry domes, flowsShoshonite flow, cinder cone

EXPLANATION

Table Mountain


Figure 17. Major-element classification diagrams for 24- to 36-Ma volcanic rocks (units Tlal, Tlau, Tla, Ta, and Td) in Santa Maria Moun-tains, Juniper Mountains, and Martin Mountain. Data from this study, Ash (1997), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

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40 50 60

A/C

NK


SiO2 (wt. percent)

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

EXPLANATION

Juniper MountainsDenny MountainHyde Creek MountainIndian PeakBear MountainMartin Mountain


Figure 18. Major-element classification diagrams for Paleocene and Late Cretaceous plutonic rocks (units Kt, TKgd, and TKr) in Brad-shaw Mountains. Data from this study, Sturdevant (1975), Lindgren (1926), Anderson and Blacet (1972b), and Vrba (1980). A, R1R2 major-element classification diagram (De la Roche and others, 1980). Gb-Di, gabbro-diorite; Mz Gb, monzogabbro; Sy Gb, syenogabbro; Sy Di, syenodiorite; Mz, monzonite; Mz Di, monzodiorite; Di, diorite; Sye, syenite; Q Sy, quartz syenite; Q M, quartz monzonite; Ton, tonalite; Alk Gr, alkali granite; Gr, granite; Gd, granodiorite. Fields of alkalinity from Fridrich and others (1998). B, Alumina saturation diagram (SiO2 versus A/CNK). A, molar Al2O3; C, molar CaO; N, molar Na2O; K, molar K2O. Field of unal-tered igneous rocks from DeWitt and others (2002). C, Alkali classification diagram ((K2O/K2O + Na2O) versus SiO2). Field boundaries from Fridrich and others (1998). Red arrow indicates point lies outside of plot, in direction indicated. D, Iron enrichment classification diagram (FeO + 0.89*Fe2O3)/(FeO + 0.89*Fe2O3 + MgO) versus SiO2. Field boundaries from DeWitt and others (2002).

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

80

70

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK

Field of unalteredigneous rocks

SiO2 (wt. percent)

B

WalkerPoland JunctionCrown KingNortheast of CleatorDikes

EXPLANATION


Base-andprecious-metaldepositslocalizedalongmanyaltereddikes(Keithandothers,1984)

Kt Tonalite (Late Cretaceous)—StocksatCopperBasin,Walker,PolandJunction,andCrownKing,anddikesthroughoutBradshawMountains.SmallerstockatPineFlat,southofBigBugMesa.Areallymoderate-sizegravitylowsofabout6mGalassociatedwithPolandJunctionandWalterstocks(Langenheimandothers,2002,fig.8).East-westzoneoflowmagneticintensitycorrespondswithoutcropofPolandJunctionstock(U.S.GeologicalSurvey,1972).Northeast-southwestzoneofhighmagneticintensityassociatedwithWalkerstock(U.S.GeologicalSurvey,1972).PossibleburiedstocksuggestedbybouldersofgranodioriteinsedimentaryrocksatbaseofHickeyFormationalongVerdefault,eastofCherry.Stockwouldextendtothesouth,towardInterstate17.Anareallymoderate-sizegravitylowextendingacrossInterstate17maysupporttheinterpretationofaburiedstock(Langenheimandothers,2002,fig.8),butalsocouldbecausedbyanunderlying,low-densityEarlyProterozoicstock.Aeromagneticdataareequivocal(Langenheimandothers,2002,fig.5b).Textureandmineralogyofigneousrocksfromonestocktoanotherareverysimilar.Groundmassoffine-grainedquartz,feldspar,andbiotitecontainingphenocrystsofbiotiteandhornblende.Rangesincompositionfromcalc-alkalicmonzodioritetocalc-alkalicgranodiorite(fig.18A)andaveragesalkali-calcictocalc-alkalictonalite.Averagetonaliteismetaluminoustomildlyperaluminous(fig.18B),verysodictosodic(fig.18C),andMgrichtoaverageinFe/Mgratio(fig.18D).

K-ArbiotiteandhornblendedatesofCopperBasinstockare73Ma(Christman,1978).K-ArhornblendedateofWalkerstockis64Ma.K-ArbiotitedateofPolandJunctionstockis70Ma.K-ArbiotitedateofCrownKingstockis65Ma.

Extensivehydrothermalalteration,veining,andmineralizationassociatedwithmoststocks.Base-andprecious-metalveindepositsspatiallyassociatedwithmoststocks(Keithandothers,1984;Weltyandothers,1985;Weltyandothers,1989).Brec-ciaslocalizedalongrhyolitedikesandmarginofstockatCrownKing(Ball,1983;BallandCloss,1983).Gold-richbrecciapipeslocalizedinstockatCopperBasin(JohnstonandLowell,1961).Silver-richveinslocalizedalonggranodioriteporphyrydikesandinstockatPolandJunction(Sturdevant,1975).Zonationofbase-andprecious-metalscommonatWalkerandPolandJunctionstocks(O’Haraandothers,1991)

MESOZOIC SEDIMENTARY ROCKS

dm Moenkopi Formation (Middle? and Lower Triassic)—Redtopurplemudstone,shale,andsandstone.Presentonlyinfarnorth-centralpartofmaparea,alongMogollonRim,nearSycamoreCanyon.Partiallyerodedthicknesslessthan50m

PALEOZOIC SEDIMENTARY ROCKS

Pk Kaibab Limestone (Lower Permian)—Gray,sandydolomiticlimestoneanddolomite,limestone,andminorchert.Thicknessabout150m

Pt Toroweap Formation (Lower Permian)—Light-graysandstone.Thicknessabout80mPkt Kaibab Limestone and Toroweap Formation, undivided (Lower Permian)—Gray

dolomite,limestone,andminorchertoftheKaibabandlight-graysandstoneoftheToroweap.Combinedthicknessabout230m

Pc Coconino Sandstone (Lower Permian)—Light-graytotan,fine-grainedeolian,crossbed-dedsandstone.Thicknessasmuchas240mnearSedona.Thinstothewest.Thick-nessnorthofClarkdaleabout160–210m

Ptc Toroweap Formation and Coconino Sandstone (Lower Permian)—Sandstone.Com-binedthicknessabout240–320m

Psh Schnebly Hill Formation (Lower Permian)—Tantolight-gray,eolian,crossbeddedsand-stoneandminormudstone,limestone,andevaporiticbeds(Blakey,1980;BlakeyandKnepp,1989;Blakey,1990).Regionally,correlateswithupperpartofSupaiGroup.ThicknessnearSycamoreCanyonabout195m.ThicknessatSedonaabout225m.ThicknessatWestClearCreekabout275m.Thinstothewest


Ph Hermit Formation (Lower Permian)—Reddish-brownsandstone,mudstone,andpebbleconglomerate.UncertaintyaboutregionalcorrelationsuggeststhatthisunitmightbeequivalenttoSupaiPS2ofMcKee(1975).ThicknessinSedonaareaandnearSyca-moreCanyonabout90m.Thinstothenorthwest

Pshh Schnebly Hill and Hermit Formations, undivided (Lower Permian)—Sandstone,silt-stone,andminorconglomerate.Thicknessabout290–350m

hs Supai Formation (Lower Permian to Upper Mississippian (or Upper Pennsylvanian of Blakey))—Redsiltstone,sandstone,siltydolomite,andminorconglomerate.ReferredtoasEsplanadeSandstone(LowerPermian)inSedonaarea(BlakeyandKnepp,1989;BlakeyandMiddleton,1998).ProbablyequivalenttoSupaiPS1ofMcKee(1975;McKee,1982).ThicknessnearSedonaabout55m.Thickenstothenorthwest.Thick-nessnearSycamoreCanyonabout190m

Phss Schnebly Hill, Hermit, and Supai Formations, undivided (Lower Permian and Upper Pennsylvanian)—Sandstone,siltstone,andminordolomiteandconglomerate.Thick-nessabout330minmaparea

Mr Redwall Limestone (Mississippian)—Graylimestoneandminorchert.Extensivekarstdevelopmentandcollapsefeaturesinupperandlowerparts.Thicknessabout75–85m

Dm Martin Formation (Upper and Middle? Devonian)—Dark-graydolomite,minorlime-stone,andsandysiltstone.Thicknessabout105–145m

MDrm Redwall Limestone and Martin Formation, undivided (Mississippian through Middle? Devonian)—Limestoneanddolomite.Combinedthicknessabout180–230m

Demt Martin Formation and Tapeats Sandstone, undivided (Upper Devonian through Lower Cambrian)—Dolomiteandsandstone.Thickness120–230m

eb Bright Angel Shale (Middle Cambrian)—Grayshaleandminordolomite.IncludessomeMuavLimestone.Thicknessabout7–40minmaparea.Thickenstothewest

et Tapeats Sandstone (Middle and Lower Cambrian)—Reddish-brownsandstoneandcon-glomerate.MapunitincludesChinoValleyFormation(Devonian?orageunknown)attopofunit.Thicknessabout15–85m.Thickenstothewest

ebt Bright Angel Shale and Tapeats Sandstone, undivided (Middle and Lower Cam-brian)—Shaleandsandstone.Combinedthickness25–130m

MIDDLE PROTEROZOIC INTRUSIVE ROCKS

Ygb Gabbro—Dikesandsillsofgabbrotosyenogabbro.Conspicuousdiabasictexture.Somesillsveryirregularlyshaped.Chemicallyisalkali-calcictoalkalic,metaluminous,veryFerich,andpotassictoveryKrich.Agenotdeterminedinarea,butischemicallysimi-lartoinformallynamed1.1-GaApachediabaseincentralArizona(SmithandSilver,1975;Wrucke,1989),innorthwesternArizona(Shastriandothers,1991),andintheGrandCanyon(Timmonsandothers,2001).Individualdikesandsillsasmuchas20mthick.DiscontinuouslyexposeddikesnortheastandnorthwestofCrownKingasmuchas6kmlong.Low-angledikesnearIronSpringsaremorenumerousthanindicatedatscaleofmap.

Swarmsofeast-striking,high-angledikescutallEarlyProterozoicmetavol-canicrocksintheBlackHillsandthemassivesulfideorebodyandgabbroatJerome(AndersonandCreasey,1958,fig.12;P.A.Lindberg,unpub.mapping,1991).Dikesaretoosmalltoshowatscaleofmap.DikesdonotextendintooverlyingPaleozoicstrata.LimitedchemicaldatasuggestthattheleastaltereddikeinUnitedVerdemineisacalc-alkalicgabbrothatisAlrich,verypotassic,andveryFerich.Titaniumandphosphorusanalysesarenotavailable,whichwouldaidinclassificationofmaficdikes.SomemaficplutonicrockthatcutsmetarhyolitewestofCopperChiefminemaybe,inpart,diabaseofMiddleProterozoicage

Yg Granite of Granite Basin—Coarse-grained,stronglyporphyriticbiotitegranitecontainingphenocrystsofmicrocline.InformallynamedhereinforexposuresinGraniteBasin,westofSkullValley.Chemicallyisalkali-calcic(fig.19A),mildlyperaluminous(fig.19B),andaverageinbothK/NaandFe/Mg(figs.19C,D).Similarinmineralogy,chemistry,andtexturetogranodioriteofYava(unitYy).PresumedtobeMiddleProterozoic


Figure 19. Major-element classification diagrams for 1,400-Ma plutonic rocks (units Ywc, Yy, Yg, and Ykp) between Skull Valley and Juniper Mountains. Data from this study and C.M. Conway in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 18.

60

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2 (w

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D

30002500200015001000

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0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

80

70

60

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K2O/K2O + Na2O

SiO

2 (w

t. p

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C

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0.8

0.9

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1.1

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A/C

NK


SiO2 (wt. percent)

B

Walnut Creek (Ywc)Yava (Yy)Granite Basin (Yg)Kirkland Peak (Ykp)Yarnell [not a map unit]

EXPLANATION


Ywc Granite of Walnut Creek—Undeformed,medium-grainedbiotite-muscovitegraniteinfarwesternpartofmaparea,fromNorthForkofWalnutCreekonthenorthtosouthofCampWoodonthesouth.Southwestofmaparea,nearBlackPearltungstenmine,alsoconsistsofgranodiorite.InformallynamedhereinforexposuresalongWalnutCreek,northofCampWood.Bodyrangesincompositionfromgranodiorite(exposedonlynearBlackPearlmine)toalkaligranite(fig.19A),whichisrepresentativeofmostofbodyinmaparea.Granitetoalkaligraniteinmapareaisalkali-calcic(fig.19A),stronglyperaluminous(fig.19B),averagetoverypotassic(fig.19C),andaveragetoMgrich(fig.19D).Ageundetermined,butchemicallysimilartoknown1,400-MaplutonsincentralArizona(Bryantandothers,2001)

Ywcb Breccia in granite of Walnut Creek—Angularfragmentsofcobble-sizeandsmallergranodioriteandgraniteinmatrixoftonaliteandmoremaficmaterial.Onlyoneknownoutcrop,southofCottonwoodMountain.Chemically,matrixmaterialisalkali-calcictonalitethatismetaluminousandFerich

Ykp Granite of Kirkland Peak—Undeformed,medium-tofine-grained,stronglyjointed,equi-granularmuscovite-bearingalkaligranite.InformallynamedhereinforexposuresonKirklandPeak,southwestofSkullValley.CutsgranodioriteofYava(unitYy).Incor-rectlyreferredtoasLawlerPeakGranite(DeWitt,1987,unitYl,fig.32)andasSkullValleyMonzogranite(Anderson,1989b).Chemicallyisalkali-calcic(fig.19A),mildlyperaluminous(fig.19B),verysodic(fig.19C),andveryFerich(fig.19D).PresumedtobeMiddleProterozoic

Yd Dells Granite—Fine-tomedium-grained,highlyjointedalkaligranite(Krieger,1965).ExposedonlynorthofPrescott.Bodyismildlytostronglyperaluminous(fig.20B),averagetoverysodic(fig.20C),andFerichtoveryFerich(fig.20D).AnareallyextensivegravitylowextendsfromsouthwestofPrescotttonorthofexposuresofDellsGranite(Langenheimandothers,2002).ModelingofgravitylowsuggeststhatadeeplyrootedbodyofeitherPrescottGranodioriteorDellsGranitecouldberesponsibleformuchofgravitylow(Cunion,1985).U-Pbzirconage1,395Ma(Silverandothers,1984)

Yy Granodiorite of Yava—Undeformed,coarse-grained,stronglyporphyriticbiotitegrano-dioritecontainingphenocrystsofmicrocline.InformallynamedhereinforexposuresatandnorthofYava,justsouthofThompsonValley,insouthwesternpartofmaparea.Formslargeplutonsouthwestofmaparea.Rangesfromgranodioritetogranite(fig.19A)andismetaluminoustomildlyperaluminous(fig.19B),averagetopotassic(fig.19C),andaverageinFe/Mgratio(fig.19D).TextureandchemistrysuggestthisbodyisnorthernequivalentofgraniteofGraybackMountain,inAlamoLake1:100,000quadrangletothesouthwest(Bryant,1995;Bryantandothers,2001).U-PbzirconageofgraniteofGraybackMountainis1,415Ma

MIDDLE(?) AND EARLY(?) PROTEROZOIC INTRUSIVE ROCKS

YXgr Granite—Medium-grained,equigranularbiotitegranite.Mildlyflowfoliatedtounde-formed.IncludeslargebodynearSouthMesainfarwest-centralpartofmapareathatcropsoutincentralpartofgraniteofWalnutCreek(unitYwc).Alsoincludessmallerbodiestotheeast,northofSheridanMountain.PresumedtobeMiddle(?)andEarly(?)Proterozoic

EARLY PROTEROZOIC INTRUSIVE ROCKS

[EarlyProterozoicplutonicrocksarewidelyexposedthroughoutmaparea.Inordertoaidinthediscussionoftheserocks,theexposuresofplutonicandmetavolcanicrocksaredividedintosixzones(fig.21,zones1–6,fromwesttoeast).Thesezonesareroughlyparalleltoregionalfoliationandcontainrockunitsthataresimilartooneanother.Thezonesarenotcrustalblocksnoraretheynecessarilyseparatedfromoneanotherbydiscretetectonicstructures]

Gabbroic rocks—Mafictoultramaficintrusiverocks.Gabbroandgabbro-noritearethemostcommonrocktypes(fig.22A)andarefoundinallzonesinthePrescott-Jeromearea(fig.21).Significantexposuresofultramaficrocksarepresentonlyinzone2,inthePrescottarea.Evolvedrocks,suchasdioriteandmonzodiorite(fig.22A),are



Figure 20. Major-element classification diagrams for 1,400-Ma Dells Granite (unit Yd) north of Prescott. Data from Fleck (1983). Rock abbreviations and field boundaries defined in figure 18.

SiO

(w

t. p

erce

nt)

2

2 3 2 3(FeO + 0.89Fe O )/(FeO + 0.89Fe O + MgO)

60

500.5 0.6 0.7 0.8 0.9 1.0

D

SiO

(w

t. p

erce

nt)

2

K O/(K O + Na O)2 2 2

60

500 0.2 0.4 0.6

C

A

30002500200015001000

500

1000

1500

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Calc-Alkalic

Alkali-Calcic

Alkalic

R =

600

0Ca

+ 20

00M

g +

1000

Al

2

R = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)1

A/C

NK

SiO (wt. percent)2

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70


B

Dells Granite> 0.15% TiO2

0.1-0.14% TiO2

0.05-0.09% TiO2

0.01-0.04% TiO2

EXPLANATION


Figure 21. Locations of geochemical zones (1–6) in map area. Zones 1–5 referred to as being in Prescott and Bradshaw Mountains areas. Northern part of zone 6 referred to as being in Jerome area. Southern part of zone 6 referred to as being in Dugas area.

Map boundaryPrescott NationalForest boundary

Ash Fork

Paulden

ChinoValley

Prescott

Camp Wood

Humboldt

Jerome

SkullValley

Yarnell

Flagstaff

Sedona

Camp Verde

Crown King

Mayer

Agua

Fria

River

VerdeRiver

Verde River

Big Chino Valley

Little Chino Valley

Verde Rivervalley

BradshawM

tsBlack Hills

Santa Maria Mts

Will

iam

son

Valle

y

Weaver

Mts

0 10 KILOMETERS

Perkinsville

113°

35°

112°

34°30'

89

89A

69

89

93

17

89A

17

Juniper Mts Big Black Mesa

40 40

Kirkland

Mt. Hope

Picacho Butte

0 6 MILES

Valentine Williams Flagstaff

Bagdad Prescott Sedona

Bradshaw Mountains Payson

Cottonwood

Dugas


Figure 22. Major-element classification summary diagrams for Early Proterozoic gabbros (units Xum, Xgb, Xlgb, and Xdi) from zones 1–5 in Bradshaw Mountains and zone 6 in the Black Hills and near Dugas. Data from this study, L.D. Nealey in Baedecker and others (1998), and Vance (1989). A, R1R2 major-element classification diagram (De la Roche and others, 1980). Picritic, ultramafic rocks; Gb-No, gabbro-norite; Gb, gabbro; Alk Gb, alkali gabbro; Thr, theralite; Sy Gb, syenogabbro; Mz Gb, monzogabbro; Gb-Di, gabbro-diorite; Sy Di, syenodiorite; Mz, monzonite; Mz Di, monzodiorite; Di, diorite; Q Sy, quartz syenite; Q M, quartz monzonite; Ton, tonalite; Gr, granite; Gd, granodiorite. Fields of alkalinity from Fridrich and others (1998). B–D, Field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

CalcicCalc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

EXPLANATION

Gabbroic rocks Zones 1-5 Zone 6

presentonlyincentralpartofmaparea,inzones2,3,and4.Manygabbrosinzone6(Jeromearea)areAlrichandplotabovethefieldofunalteredrocks(fig.22B);rocksarenotaltered,butarerichinCa-plagioclase.High-Alrocksarenotedinzones2,3,and5,butareespeciallyabundantinzone6.GabbroshaveawiderangeofK/NaandFe/Mgratios(figs.22C,D);nospatialvariationsareevident.Onlytheevolvedrocksinzone3areTirich.Ageundetermined,butcross-cuttingrelationsindicatethatgabbrosaretheoldestplutonicrocksinmaparea.Discussedfrommostmafictomostfelsic,andportrayedinchemicaldiagramsfromwest(zone1)toeast(zone6)(figs.23–27)

Xum Ultramafic rocks—Medium-tocoarse-grained,equigranular,hornblende-andpyrox-ene-richpicriticrocks.ExposedsouthandeastofPrescott,inamassthatextendsfromBadgerMountain,eastofPrescott,south-southwesttonorthofGroomCreek.Foliatedonmarginsandinsomelocalizedzonesofhighstrain.Igneouslayeringonasmallscalehasbeendescribedfromthebody(Krieger,1965).Picriticrocksrangewidelyintheirchemistryduetotheirextremesofmineralogy;plagioclase-richrocksplotabovethefieldofunalteredrocks(fig.24B)duetocrystalaccumulation.Amphibole-andpyroxene-richrocksplotbelowthefield,theirpositionalsoisprobablyduetocrystalaccumulation.Plagioclase-richrocksaresodic;amphibole-richrocksareverypotassic(fig.24C).AllrocksareveryMgrich(fig.24D).

Smalleast-strikingbodycomposedprimarilyofaugitelocatedsouthofJerome,nearDelMonteGulch.Plagioclaseisinterstitialtoaugite,whichisrimmedbyhorn-blendeandchlorite.

SmallbodyofhornblenditelocatednorthwestofTuscumbiaMountainXgb Gabbro—Medium-tocoarse-grained,equigranular,hornblende-richgabbro-norite,

gabbro,andgabbro-diorite.ExposedaslargebodiesthroughoutcentralBradshawMountains(zones2–5).SmallerbodiesexposednearJerome,intheBlackHills(zone6),especiallywithinGrapevineGulchVolcanics.MildlytostronglydeformedandmetamorphosedincentralBradshawMountains.Largerbodieshaveonlylocalizedzonesofhighstrain;smallerbodiesaremorethoroughlydeformed.UndeformedandonlymildlymetamorphosedinBlackHills.

Largestgabbromassisexposedinzone2,westofPrescott,andiscenteredonSugarloafMountain.Compositionsrangefromgabbro-noritetodiorite(fig.23A),andincludeabundantleucogabbrobodiestoosmalltoshowonmap.Zone2containsahigherpercentageofgabbro-noritethanmostotherzones(fig.23A),andhassomeofthemostprimitivechondrite-normalizedrare-earth-element(REE)profiles.

Zone3containsthreelargegabbromasses.OneextendsnorthfromLongfel-lowRidgetowestedgeofBigBugMesa,andisreferredtoastheDandreaRanchmass,foralocalitywestofBigBugMesa.Another,possiblyrelatedtothefirst,iscenteredonBodiemine,westofCrooksCanyon.ThelastiscenteredonSalidaSpring,eastofPrescott.AprominentaeromagnetichigheastofPrescottisspatiallyassociatedwiththismass(Langenheimandothers,2002,fig.5b).Chemistryoffirsttwobodiesissimilar,rangingfromgabbro-norite,throughgabbro,togabbro-diorite(fig.24A).WiderangeinbothK/NaandFe/Mgratios(figs.24C,D)andnoobvioussystematicpatternmaysuggestcomplexintrusivemixturesinthetwobodies.SalidaSpringbodycon-tainssmall-scaleigneouslayersdefinedbyeast-strikingflowfoliation.BoththeSalidaSpringgabbroicbodyandtheBadgerMountainultramaficbodyhavedistinctiveREEpatternswithpronouncedpositiveEuanomalies,suggestiveofcrystalaccumulationofplagioclase.

Manysmallgabbrobodiesareexposedinzone4,thelargestofwhichisattheBlueBellmine.Chemistryofmostbodiesissimilar(fig.25A)andshowslittlevaria-tion(figs.25C,D).

ManygabbrobodiesinJeromearea(zones6Aand6B)aredistinctivebybeinghighAlandplagioclaserich(fig.27B),similartothoseinzone5(fig.26).UndergroundsamplesofgabbroatUnitedVerdeminearenotablyAlrich,andcouldrepresentplagioclasecumulatesofleucogabbro,assuggestedbytheirsodicnature(fig.27C)andFe-toveryFe-richnature(fig.27D)


Figure 23. Major-element classification diagrams for Early Proterozoic gabbros (units Xgb and Xlgb ) from zone 2 in Bradshaw Moun-tains. Data from this study. Rock abbreviations defined in figure 22; field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-AlkalicAlkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

High-Al rocks: West Sugarloaf Mountain leucogabbroHigh-Ti rocks: none

KirklandSkull ValleyWest Sugarloaf MountainWest Maverick Mountain

EXPLANATION


Figure 24. Major-element classification diagrams for Early Proterozoic gabbros (units Xum, Xgb, Xlgb, and Xdi) from zone 3 in Bradshaw Mountains. Data from this study, Anderson and Blacet (1972b), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations defined in figure 22; field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

High-Al rocks: 1 at Spruce Mountain 1 at Badger Mountain 1 at Dandrea RanchHigh-Ti rocks: 2 at Dandrea Ranch

Spruce MountainPotato PatchBadger Mountain–Groom CreekLynx CreekDandrea RanchSalida SpringGreen Gulch

EXPLANATION


Figure 25. Major-element classification diagrams for Early Proterozoic gabbros (units Xgb and Xdi ) from zone 4 in Bradshaw Mountains. Data from this study, Anderson and Blacet (1972b), and Blacet (1985). Rock abbreviations defined in figure 22; field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

High-Al rocks: Towers MountainHigh-Ti rocks: 1 at Humboldt (moderate)

HumboldtPoland Junction and southBluebell mineTowers MountainWest of Lane Mountain

EXPLANATION


Figure 26. Major-element classification diagrams for Early Proterozoic gabbros (units Xgb and Xdi) from zone 5 in Bradshaw Moun-tains. Data from this study, Anderson and Blacet (1972b), and Anderson (1972). Rock abbreviations defined in figure 22; field boundaries defined in figure 2.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

High-Al rocks: Badger Spring, Yarber SpringHigh-Ti rocks: none

EXPLANATION

Badger SpringYarber SpringNew River


Figure 27. Major-element classification diagrams for Early Proterozoic gabbros (unit Xgb) and tonalite (unit Xdi?) from zones 6A and 6B in the Black Hills and from zone 6B in Dugas area. Data from this study, Vance (1989), Anderson and Creasey (1958), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations defined in figure 22; field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


SiO2 (wt. percent)

High-Al rocks: Half of Grapevine Gulch Hull Canyon Half of United Verde mine, surface All of United Verde mine, undergroundHi-Ti rocks: none

EXPLANATION

Along Yaeger CanyonCut Grapevine Gulch FormationHull CanyonUnited Verde mine, surfaceUnited Verde mine, undergroundHutch MesaTule MesaSouthwest Verde River valley


Xlgb Leucogabbro—Medium-grained,equigranular,plagioclase-richleucogabbro.Extens-ivelyexposedonSugarloafMountain(zone2)andonAshCreekRidge,westofCrooksCanyon(zone3).Undeformedtomildlyfoliated.Smalldikes,sills,andirregularlyshapedbodiescutnormalgabbroandarecutbynormalgabbro.Onechemicalanalysisindicatesgabbrocomposition(fig.23A)thatisverypotassic(fig.23C)andveryMgrich(fig.23D).REEpatternhaspositiveEuanomaly

Xdi Diorite—Medium-tocoarse-grained,equigranular,hornblende-richdioritetomonzo-diorite.ExposedinmappedbodiesatTowersMountainnorthwestofCrownKing;atGreenGulch,northwestofIronKingmine;andinDandreaRanchmass,incentralBradshawMountains.Alsopresent,butnotmappedseparately,withinbodiesofgab-broatSugarloafMountain,atSpruceMountain,southofHumboldt,andsoutheastofTownsendButte.Related(?)bodiesoftonalitecutfelsicmetavolcanicrocksonTuleMesa.MildlydeformedinmostoutcropsinBradshawMountains.UndeformedonTuleMesa.

TowersMountainandGreenGulchmassesarecalc-alkalic(fig.25A)andhaveaverageK/NaandFe/Mgratios(figs.25C,D).DandreaRanchmassisalkali-calcic(fig.24A),sodictopotassic(fig.24C),andaveragetoveryFerich(fig.24D).TonaliteonTuleMesaiscalc-alkalic(fig.27),verysodictosodic(fig.27C)andaver-ageinFe/Mgratio(fig.27D).TonaliticcompositionofTuleMesamassmayindicaterelationtoyounger,intermediate-compositionplutonicrocks

Tonalitic rocks—Maficintrusiverocks,primarilyhornblendebearing.Formlargeplutonsinwest-centralandeast-centralpartsofmaparea.Discussedfrommostmafictomostfelsic.Mostabundantinzones5and6;lessabundantinzone2.Minorbodyinzone1.Tonaliticrocksrangeincompositionfromgabbro-dioritetogranodiorite(fig.28A),andareaveragetoverysodic(fig.28C)andveryMgrichtoFerich(fig.28D).Tonaliticrocksarecalcicinzones5and6,butarecalc-alkalicinzone2(fig.28A).Chemistryofindividualrockunitssummarizedfromwesttoeast(figs.29–34)

Xch Cherry Tonalite—Medium-tomedium-coarse-grainedhornblende-biotitedioritetogranodioritecontainingphenocrystsofhornblende(AndersonandCreasey,1967).IncludestonaliteofCherry(DeWitt,1989),andpartofCherrybatholith(Anderson,1989a).NewlynamedhereinforexposuresnearCherry.TypeareaisdesignatedwheremainmassexposedfromnorthofCherrytofarsoutheasternpartofmaparea.SmallerbodiesexposedalongeastsideofLonesomeValley.Prominentnorth-trendingzoneofhighmagneticintensityalongeasternLonesomeValleyprobablymarkswesterncontactofCherryTonalitewithmetavolcanicrocks(Langenheimandothers,2002).MostmaficalongwesternmarginofmainmassandinsouthernLonesomeValley.ExposedinerosionalhighsbeneathTertiarybasaltfromInterstate17tosouthernmarginofmaparea.CutsBishopSpringGranodiorite(unitXbp)northwestofRuggedMesa.CutsBlandTonalite(newlynamed,unitXbl)eastofPerryMesaandsouthofmaparea,alongSquawCreek.Undeformedinmostoutcrops,butmildlytostronglyflowfoli-atedinplaces.StronglydeformedalongShylockfaultandShylockhigh-strainzoneinsouthwesternBlackHills.Hostsgold-bearingquartzveinsinCherrydistrictthataregeneticallyrelatedtothetonalite(Clements,1991).

Chemicallyiscalc-alkalic(fig.34A),sodictoverysodic(fig.34C),andveryMgrichtoFerich(fig.34D).

AgeofsamplefromnearCherry,fromU-Pbzirconanalyses,is1,740Ma(Andersonandothers,1971).K-Arhornblendedatesof1,694and1,690MaobtainedfromsamplesnearCherry(Lanphere,1968;DalrympleandLanphere,1971).40Ar/39Artotalfusiondateof1,709Maobtainedfromonehornblende(DalrympleandLanphere,1971).K-Arbiotitedatesof1,689–1,693Maalsoobtainedfromsamesamples.Con-flictingage(cuts1,720-MaBlandTonalitebuthasU-Pbzirconageof1,740Ma)maybeduetomorethanonetonalitebodywithinacompositepluton(Anderson,1989a)

Xchg Granophyre of Cherry—Medium-grained,equigranularquartz-feldspargranophyre(AndersonandBlacet,1972a).ExposedsoutheastofDewey.Undeformed.CutsCherryTonalite(unitXch).Chemicallyisanalkali-calcictocalcicgranite(fig.34A)



Figure 28. Major-element classification summary diagrams for Early Proterozoic plutonic rocks from zones 1–6 in Bradshaw Mountains and the Black Hills. Data from this study, DeWitt (1989), Anderson and Blacet (1972b), Anderson (1972), Anderson and Creasey (1958), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 18.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

80

70

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

BZones 1-6All tonalitic through alkali granitic rocks

EXPLANATION


Figure 29. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xsb, Xtc, Xob, Xgg, Xcm, Xdf, Xlg, Xcf, and Xap) from zone 1 in Bradshaw Mountains. Data from this study, DeWitt (1989), and Arney and others (1985). Rock abbreviations and field boundaries defined in figure 18.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

80

70

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

South Butte (Xsb)Tucker Canyon (Xtc)Orejano Basin (Xob)Gneissic granite (Xgg)Cottonwood Mountain (Xcm)Dillon Field (Xdf)Leucogranite (Xlg)Cornfield Mountain (Xcf)Aplite-pegmatite (Xap)

EXPLANATION


Figure 30. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xmw, Xrg, Xsv, Xpv, Xwv, Xpr, Xgc, Xvr, and Xkw) from zone 2 in Bradshaw Mountains. Data from this study, DeWitt (1989), Krieger (1965), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 18.

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

EXPLANATION

Mint Wash (Xmw)Ramsgate (Xrg)Skull Valley (Xsv)Peeples Valley (Xpv)Williamson Valley (Xwv)Prescott (Xpr)Government Canyon (Xgc)Verde River (Xvr)Kings Well (Xkw)


Figure 31. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xcc, Xjf, Xcca, and Xwg) from zone 3 in Bradshaw Mountains. Data from this study, DeWitt (1989), Krieger (1965), and Anderson and Blacet (1972b). Rock abbreviations and field boundaries defined in figure 18.

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

Crooks Canyon, main (Xcc)Crooks Canyon aplite (Xcca)Wagoner (Xwg)Johnson Flat (Xjf)

EXPLANATION


Figure 32. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xhm, Xhy, Xbb, Xmh, Xhc, and Xcb) from zone 4 in Bradshaw Mountains. Data from this study, DeWitt (1989), Blacet (1985), and Vrba (1980). Rock abbreviations and field bound-aries defined in figure 18.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

Horse Mountain (Xhm)Hassayampa (Xh)Brady Butte (Xbb)Tuscumbia (Xbb)Minnehaha (Xmh)Humbug Creek (Xhc)Crazy Basin (Xcb)

EXPLANATION


Figure 33. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xbg, Xbl, and Xbs) from zone 5 in Bradshaw Mountains. Data from this study, DeWitt (1989), and Anderson (1972). Rock abbreviations and field boundaries defined in figure 18.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

Big Bug (Xbg)Bland (Xbl)Bumblebee (Xbl)Badger Spring (Xbs)

EXPLANATION


Figure 34. Major-element classification diagrams for Early Proterozoic plutonic rocks (units Xch, Xchg, Xchd, Xbp, and Xbn) from zone 6 in the Black Hills. Data from this study, DeWitt (1989), Anderson and Creasey (1958), Krieger (1965), Anderson and Blacet (1972b), Wolfe (1983), and L.D. Nealey in Baedecker and others (1998). Rock abbreviations and field boundaries defined in figure 18. Red arrow indicates point lies outside of plot, in direction indicated.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

Cherry, main (Xch)Cherry granophyre (Xchg)Dike cutting Cherry (Xchd)Bishop Spring (Xbp)Bloody Basin (Xbn)

EXPLANATION

thatismildlytostronglyperaluminous(fig.34B),verysodic(fig.34C),andaveragetoveryFerich(fig.34D)

Xchd Dikes of Cherry—Medium-grained,equigranulargranodioritetomedium-grained,porphyriticgranodioritecontainingphenocrystsoffeldsparandquartzinnorth-striking,high-angledikeswarms.Equigranulargranodioritedikesandporphyriticdikescon-tainingquartzphenocrystsarelatecogeneticbodiesrelatedtothemaintonalitemass,asevidencedbyimmiscibleigneoustextures.PorphyriticgranodioritedikesmayberelatedtoBadgerSpringGranodiorite(unitXbs).Alldikesundeformed.Ageofcogeneticdikesprobablyabout1,700Ma,assuggestedbyhornblendeandbiotiteK-Ardatesof1,690–1,709Ma

Xbl Bland Tonalite—Medium-grained,equigranulartoslightlyporphyritictonalitedioritecontainingphenocrystsofhornblende(Jerome,1956).Exposedinsoutheasternpartofmaparea,fromeastofCleatortopastsouthernboundaryofmaparea.BumblebeeGranodiorite(AndersonandBlacet,1972c)combinedwithBlandforpurposesofthismap.BumblebeemaybeslightlyolderthanmainmassofBland(seebelow).NamedhereinforexposuresattypeareaonBlandHillinsouthernpartofmapareaandalongBlackCanyon.Leastdeformedinnorthernandwesternpartsofpluton.StronglydeformedwithinBlackCanyonhigh-strainzone.CutsgranodioriteofBigBugCreek(unitXbg).

Rangesincompositionfromgabbro-dioritetogranodioriteandispredominantlycalcic(fig.33A).Tonaliticrocksareverysodictoaverage(fig.33C)andMgrichtoFerich(fig.33D).

AgeofBlandabout1,720Ma(Bowringandothers,1986).AgeofBumblebeeabout1,750Ma(S.A.Bowring,unpub.U-Pbzircondata,citedinKarlstromandothers,1987),indicatingthatBumblebeemaybeolderthanBland

Xgc Government Canyon Tonalite—Medium-grained,equigranularhornblende-biotitestock(Krieger,1965)havingaveragecompositionoftonalite.ExposedfromeastofGraniteMountaintosouthofWilhoit.Redescribedhereintotonalite,basedonchemicalcom-position.Undeformedinmanyeasternoutcrops,butstronglydeformedwestofCopperBasinandmildlydeformedincentralBradshawMountains.

Rangesincompositionfromalkali-calcicgabbro-dioritetocalc-alkalicgrano-diorite(fig.30A).Verysodictoaverage(fig.30C)andveryMgrichtoMgrich(fig.30D).Age,fromU-Pbzirconanalyses,isabout1,740Ma(Andersonandothers,1971)

Xcm Tonalite of Cottonwood Mountain—Medium-grained,equigranularbiotite-hornblendetonalite.ExposedonlyinsmallareawestofCottonwoodMountain,infarwesternpartofmaparea.Stronglydeformed.Chemicallyiscalc-alkalic(fig.29A),sodic(fig.29C),andaverageinFe/Mgratio(fig.29D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Granodioritic rocks—Intermediate-compositionintrusiverocks,primarilybiotitebearing,butlocallycontaininghornblende.Formsintermediate-sizeplutonsthroughoutmaparea.Mostnumerousinzone2(sevenplutons).Lessnumerousinzones1,3,and6(oneplutoneach).Mostgranodioritesaremediumgrainedandequigranular.Onlythreearestronglyporphyritic.Greatestrangeinageofmajorintrusivegroups,frompre-tectonic(about1,750Ma)topost-tectonic(about1,690Ma).Discussedfrommostmafictomostfelsic.Granodioriticrocksaremetaluminoustomildlyperaluminous,withafewassociatedrocksbeingstronglyperaluminous(fig.28B).Granodioritesareamongthemostsodicofintrusiverocks,rangingfromverysodictopotassic(fig.28C),andfromMgrichtoaverageinFe/Mgratio(fig.28D)

Xpr Prescott Granodiorite—Medium-tomedium-fine-grainedbiotitegranodiorite(Krieger,1965).ExposedfromsouthwestofPrescotttonortheasternpartofLonesomeVal-ley.Mildlyflowfoliatedinplaces.Tectonicfoliationrestrictedtominorzoneofhighstrain,noneofwhichismappableatthisscale.CutsGovernmentCanyonGranodioriteandPeeplesValleyGranodiorite(newlynamed)nearPrescottandcutsCherryTonalite(newlynamed)innortheasternLonesomeValley.


Chemicallyiscalc-alkalictoalkali-calcic(fig.30A),mildlyperaluminous(fig.30B),verysodic(fig.30C),andveryMgrichtoaverage(fig.30D).Ageabout1,690Ma(J.L.WoodenandEdDeWitt,unpub.U-Pbzircondata,1997)

Xpv Peeples Valley Granodiorite—Medium-grained,equigranularbiotitegranodioritetoleu-cocraticgranodiorite,locallycontainingequantbooksofbiotite.ExposedfromwestofPrescotttopastsouthwesternboundaryofmaparea.EquivalenttogranodioriteofWil-hoit(DeWitt,1989),andpartofWilhoitbatholithofAnderson(1989b).NewlynamedhereinforexposuresattypeareainPeeplesValley,southwestofWilhoitandnorthofYarnell(DeWitt,1989,fig.1).Undeformedinmostexposures.CutsGovernmentCan-yonTonalite.Wherefinegrained,plutonisdifficulttotellfromPrescottGranodiorite.

Granodioriteiscalc-alkalic(fig.30A),metaluminoustomildlyperaluminous(fig.30B),verysodic(fig.30C),andveryMgrichtoMgrich(fig.30D).EarlyProtero-zoicagedeterminedfromPb-Pbwholerockisotopiccomposition(WoodenandDeWitt,1991)

Xvr Granodiorite of the Verde River—Medium-grained,equigranularbiotite-hornblendegranodiorite(Krieger,1965).ExposedonlyalongVerdeRiver,downstreamfromPaul-den.Mildlydeformedinmostoutcrops.Limiteddatasuggestbodyisalkali-calcic(fig.30A),verysodic(fig.30C),andveryMgrich(fig.30D).Age,determinedfromU-Pbanalysesofzircon,about1,720Ma(Chamberlainandothers,1991)

Xhy Hassayampa Granodiorite—Medium-tocoarse-grainedbiotitegranodioritecontainingphenocrystsofpotassiumfeldspar.Containsabundantdikesofapliteandpegmatitethatarelocallyrichintourmaline(DeWitt,1989).Exposedinfarsouthernpartofmaparea,fromnorthofGoodwinSpring(locationofHozoniRanch),toalongtheHassa-yampaRiver.ReferredtoinformallyasgranodioriteofHozoniRanch(DeWitt,1989).EquivalenttopartofporphyriticmonzograniteofHorseMountainofAnderson(1989b).NewlynamedhereinforexposuresalongHassayampaRiverandatHozoniRanch.Moderatelytostronglydeformedalongnortheast-striking,northwest-dippingfoliation.GeneticallyrelatedtopegmatitedepositsintheWhitePicachodistrict,northeastofWickenburg(Jahns,1952).

Mainbodyrangesincompositionfromcalc-alkalictonalitetogranodiorite(fig.32A).Mostmaficpartofbodyissouthwestofmaparea,nearWhitePicachopegmatitedistrict.Aplite-pegmatitedikesarealkali-calcicgranite(fig.32A).Granodioriteandaplite-pegmatitesarepredominantlyaverageinK/Naratio(fig.32C)andFe/Mgratio(fig.32D).Ageabout1,720Ma(J.L.WoodenandEdDeWitt,unpub.U-Pbzircondata,1992)

Xmh Minnehaha Granodiorite—Medium-grained,equigranularhornblende-biotitegrano-diorite(DeWitt,1989).LargestcontinuousoutcropnearandsouthofMinnehaha,itsdesignatedtypearea.SomeexposurestoosmalltoshowonmapextendfromLookoutMountaintothesouthwest.MainmassnearMinnehahaisundeformedoneasternmargin,butstronglydeformedonthewest.SmallbodiesnearLookoutMountainarestronglydeformed.NewlynamedhereinforexposuresnearMinnehaha.PreviouslyreferredtoinformallyasgranodioriteofMinnehaha(DeWitt,1989).Characteristiclowmagneticsusceptibility,similartothatofBradyButteGranodiorite(DeWitt,1989),probablyresponsibleforaeromagneticlowthatextendsfromBradyButtetonearWick-enburgMountains(U.S.GeologicalSurvey,1972;SaukandSumner,1970).Interpretedaspartofcomposite,possiblyzoned,plutonassociatedwithBradyButteGranodiorite.

Rangesfromcalc-alkalictonalitetogranodiorite(fig.32A).Metaluminoustomildlyperaluminous(fig.32B),verysodictosodic(fig.32C),andveryMgrichtoaverageinFe/Mgratio(fig.32D).Major-andminor-elementcompositionverysimilartothatofmetadacitetuffexposedonwestsideofBradyButteGranodiorite,westofBattleFlat.Couldbesubvolcanicequivalentofmetadacitetuff.EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(WoodenandDeWitt,1991)

Xbp Bishop Spring Granodiorite—Medium-grained,equigranularbiotitegranodiorite.Undeformedtomoderatelyfoliated.NewlynamedhereinforexposuresalongBishopCreek,northofRuggedMesa,insoutheasternpartofmaparea.


Granodioriteiscalcic(fig.34A),metaluminoustomildlyperaluminous(fig.34B),verysodic(fig.34C),andMgrichtoaverageinFe/Mgratio(fig.34D).Twosamplesofgranodioritearethemostsodicofallintrusiverocksinentirearea.EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Xbpr Bishop Spring Granodiorite and rhyodacite—Fine-grained,porphyriticrhyodaciteflowsandtuffscontainingphenocrystsofplagioclaseandquartzthatareextensivelyintrudedbyBishopSpringGranodiorite(newlynamedunitXbp).Rhyodaciteiscalc-alkalic(fig.46A),mildlyperaluminous(fig.46B),verysodic(fig.46C),andaverageinFe/Mgratio(fig.46D)

Xwv Williamson Valley Granodiorite—Medium-grained,equigranularbiotitegranodioritecontainingdistinctiveyellow-stainedquartzgrains(DeWitt,1989).ExposedfromnorthofPrescotttoSullivanButtes.NewlynamedhereinforexposuresinitstypeareainWilliamsonValley,westoftownofChinoValleyandnorthwestofTableMountain.Undeformedinmostexposures.

Granodioriteisalkali-calcic(fig.30A),mildlyperaluminous(fig.30B),verysodic(fig.30C),andMgrich(fig.30D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(WoodenandDeWitt,1991)

Xdf Dillon Field Granodiorite—Medium-grained,equigranularbiotitegranodiorite.ExposedfromnorthwestofDillonField,northwestofPrescott,tonearOrejanoBasininwesternpartofmaparea.NewlynamedhereinforexposuresnearDillonField,itsdesignatedtypearea.Exaggeratedflowfoliationinmanyoutcropsandprobablyemplacedascrystal-richmush.Highestmagneticsusceptibilityofanyplutonicrockinwesternpartofmaparea.

Granodioriteisalkali-calcic(fig.29A),potassic(fig.29C),andaverageinFe/Mgratio(fig.29D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Xjf Johnson Flat Granodiorite—Medium-grained,equigranularleucocraticbiotitegrano-diorite.JohnsonFlatmonzograniteofAnderson(1989b)ishereredescribedasgrano-diorite.InformallyreferredtoaswesternpartofCrooksCanyonpluton(DeWitt,1989).ExposedfromLookoutMountaintonortheastofBattleshipButte.Moderatelydeformedinmostoutcrops.AlsopresentalongBigBugCreek,northofBigBugMesa,wheredikecutsTexasGulchFormation(AndersonandBlacet,1972b).

Granodioriteiscalc-alkalic(fig.31A),mostlymildlyperaluminous(fig.31B),verysodictosodic(fig.31C),andMgrichtoaverageinFe/Mgratio(fig.31D).Chem-icallydistinctfrommainmassofnewlyrenamedCrooksCanyonGranite(unitXcc)byvirtueoflowerZrandhigherSrconcentrationsandaREEpatternthatlacksanegativeEuanomaly.PresumedtobeEarlyProterozoic

Xjgb Johnson Flat Granodiorite and gabbro migmatite, undivided—MixtureofJohnsonFlatGranodioriteandgabbrobodies.Maycontainsomeintermediate-compositionmetavolcanicrocksaswell

Xbs Badger Spring Granodiorite—Medium-grained,porphyriticleucocraticbiotitegrano-dioritecontainingdistinctivephenocrystsofquartz(AndersonandBlacet,1972c).ExposedfromnorthofCordesJunctiontocanyonofAguaFriaRiveratfarsouthernmarginofmaparea.Undeformedinmostexposures.CutsBlandTonalite(newlynamedunitXbl).

Granodioriteiscalcic(fig.33A),mildlyperaluminous(fig.33B),verysodic(fig.33C),andaverageinFe/Mgratio(fig.33D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(WoodenandDeWitt,1991).Ageabout1,740Ma(S.A.Bowring,unpub.U-Pbzircondata,citedinKarlstromandothers,1987)

Xbgb Intrusive breccia—DikesandsillsofBadgerSpringGranodiorite(unitXbs)thatcutdistinctivegabbroexposedextensivelyinNewRiverMountains,southeastofmainmaparea.LargestexposuresareincanyonofAquaFriaRiver,insoutheasternpartofmaparea.Gabbroisnon-uniformingrainsizeandcontainsabundantplagioclasepheno-crysts.Atsouthernmarginofbody,dikesandsillsofgranodioritecompose10–15


percentofbreccia.Dikesandsillsincreaseinpercentagetothenorth,composing40–80percentofbreccia.Largestinclusionsofgabbroinbrecciaare0.5mthickand3mlong

Xsv Granodiorite of Skull Valley—Medium-tomedium-fine-grainedbiotitegranodiorite,redescribedasgranodioriteforexposuresaroundthetownofSkullValley,westofPrescott.OriginallynamedSkullValleyMonzogranite(Anderson,1989b).Unde-formedinallexposures.Limiteddatasuggestgranodioriteisalkali-calcic(fig.30A),mildlyperaluminous(fig.30B),andaverageinK/NaandFe/Mgratios(figs.30C,D).SimilarinmegascopicappearancetoPrescottGranodiorite(unitXpr).EarlyProtero-zoicagedeterminedfromPb-Pbwholerockisotopiccomposition(WoodenandDeWitt,1991)

Xrg Granodiorite of Ramsgate—Medium-grained,equigranularbiotitegranodiorite.Stronglydeformedinzonesofhighstrainthatstrikenortheastanddipsteeply.ExposedalongRamsgate,westofIronSprings.CutsMintWashGranodiorite(newlynamedunitXmw).Limiteddatasuggestgranodioriteisalkali-calcic(fig.30A)andaverageinK/NaandFe/Mgratios(figs.30C,D).PresumedtobeEarlyProterozoic

Xmw Mint Wash Granodiorite—Coarse-grained,porphyriticbiotitegranitetogranodioritecontainingconspicuousphenocrystsofalkalifeldspar(DeWitt,1989).Typeareadesig-natedforexposuresalongMintWash,northwestofPrescott,andatGraniteMountain,andsouthtotownofIronSprings.StronglyfoliatedalongwesterncontactinGraniteMountainhigh-strainzoneandinnortheast-striking,steeplydippingIronSpringshigh-strainzone.Silicifiedandchloritizedwithinzonesofhighstrain.MintWashbodydoesnotcutgranodioriteofSkullValley(unitXsv),assuggestedbyAnderson(1989b).

Compositionstraddlesboundarybetweenalkali-calcicgranodioriteandgranite(fig.30A).BodyispredominantlyaverageinbothK/NaandFe/Mgratios(figs.30C,D).Ageabout1,720Ma(J.L.WoodenandEdDeWitt,unpub.U-Pbzircondata,1997)

Xbb Brady Butte Granodiorite—Medium-tomedium-fine-grained,equigranulartoslightlyporphyriticbiotitegranodiorite(Andersonandothers,1971;Blacet,1985).ExposedfromBradyButtetowestofCrownKing.Stronglydeformedwithinzonesofhighstrain.Mostdeformedonwestsideofpluton.Asmapped,includestheporphyriticgranodioriteatTuscumbia(AndersonandBlacet,1972a;Blacet,1985).Largeareaoflowmagneticintensitycorrespondstooutcropofgranodiorite(U.S.GeologicalSurvey,1972).

Granodioritestraddlestheboundarybetweenalkali-calcicandcalc-alkalic(fig.32A),andismildlytostronglyperaluminous(fig.32B),verysodictosodic(fig.32C),andpredominantlyaverageinFe/Mgratio,buttwosamplesvarywidely(fig.32D).Age,determinedfromU-Pbanalysesofzircon,about1,750Ma(Andersonandothers,1971)

Xhc Humbug Creek Granodiorite—Fine-tomedium-grained,equigranularbiotitegranodio-ritetogranite(DeWitt,1989).ExposedalongHumbugCreekandfromsouthwestofHorsethiefBasintopastsouthernboundaryofmaparea.StronglydeformedsouthofLaneMountain,especiallysouthwestofCopperBasinandalongHumbugCreek.TypeareadesignatedalongHumbugCreek.OutcropextentismorelimitedthanshowninDeWitt(1989).

Compositionstraddlesboundarybetweengranodioriteandgraniteandboundarybetweenalkali-calcicandcalc-alkalicrocks(fig.32A).Mildlyperaluminous(fig.32B),verysodic(fig.32C),andMgrichtoaverageinFe/Mgratio(fig.32D).Ageabout1,720Ma(J.L.WoodenandEdDeWitt,unpub.U-Pbzircondata,1992)

Xbg Granodiorite of Big Bug Creek—Medium-grained,equigranularbiotitegranodiorite(DeWitt,1989).ExposedbetweenCordesJunctionandCordes.Mildlydeformedwithinzonesofhighstrain.CutsBlandTonalite(unitXbl).Limiteddatasuggestgranodioriteiscalc-alkalic(calcicsamplemaybealtered;fig.33A),verysodic(fig.33C),andaverageinFe/Mgratio(fig.33D).PresumedtobeEarlyProterozoic

Granitic rocks—Felsicintrusiverockscontainingbiotiteormuscovite.Formslargeplutonsinsouthernandcentralpartsofmaparea.Mostabundantinzone1(sevenbodies).Secondmostabundantinzone3(threebodies).Notpresentinzone5.Zones2and6haveonebodyeach;zone4hastwo.Predominantlymediumtomedium-finegrained,


equigranular.Onlyonebodyismarkedlyporphyritic.Mostbodiesareyoungerthan1,720Maandarelate-tectonictopost-tectonic.Discussedfrommostmafictomostfelsic.Mostgraniticrocksarealkali-calcic(fig.28A),mildlyperaluminous(fig.28B),verysodictopotassic(fig.28C),andrangewidelyinFe/Mgratio,fromveryMgrichtoveryFerich(fig.28D)

Xwg Granite of Wagoner—Fine-tomedium-grainedleucocraticgranodiorite.InformallyreferredtoaspartofsouthernCrooksCanyonGranodiorite(DeWitt,1989).ExposedfromBlackMountain,south,topastCampbellFlat.Flowfoliatedinplaces,butnottectonicallydeformedinmostoutcrops.CutsMinnehahaGranodioriteandHassayampaGranodiorite(bothnewlynamed).

Graniteisalkali-calcic(fig.31A),mildlyperaluminous(fig.31B),sodictoaver-ageinK/Naratio(fig.31C),andaverageinFe/Mgratio(fig.31D).PresumedtobeEarlyProterozoic

Xsb Granite of South Butte—Medium-tocoarse-grained,slightlytostronglyporphyriticbio-titegranitetogranodioriteandassociatedaplite.ExposedalongbaseofSouthButte,onnorthsideofBigChinoValley,forwhichunitisinformallynamed,andwestofLime-stonePeakinfarwesternBigChinoValley.AlsoexposedalongunnameddrainagenorthandwestofSouthButte.Undeformedinmanyoutcrops,butvariablydeformedalongnortheast-striking,steeplydippingzonesofhighstrain.NorthwestofSouthButtecontainsintermediate-compositioninclusions.

Granodioritetograniteisalkali-calcic(fig.29A),mildlyperaluminous(fig.29B),potassic(fig.29C),andaverageinFe/Mgratio(fig.29D).Apliteisanalkali-calcicalkaligranite(fig.29A),andisstronglyperaluminous(fig.29B)andaverageinK/NaandFe/Mgratios(figs.29C,D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Xob Granite of Orejano Basin—Medium-tomedium-fine-grainedbiotitegranitehavingmoderateflowfoliation.Exposedinfarwesternpartofmaparea,centeredaboutOre-janoBasin,westofSycamoreCreek.Megascopicallysimilartogneissicgranite(unitXgg).

Graniteisalkali-calcic(fig.29A),mildlyperaluminous(fig.29B),andaverageinK/NaandFe/Mgratios(figs.29C,D).EarlyProterozoicageprobablefromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994),butiswithinrangeofMiddleProterozoicplutonicrocksaswell

Xcf Cornfield Mountain Granite—Medium-grained,slightlyporphyriticbiotitegranitecon-tainingdistinctivecream-colored,medium-grainedphenocrystsoffeldspar.Exposedinwesternpartofmaparea,fromnorthoftownofSkullValleytonortheastofEaglePeak.Undeformedinmostexposures,butflowfoliatedinplaces.CutsDillonFieldGrano-diorite(unitXdf)andgneissicgranite(unitXgg).NewlynamedhereinforexposuresonCornfieldMountain,itsdesignatedtypearea.

Graniteisalkali-calcic(fig.29A),predominantlymildlyperaluminous(fig.29B),averagetopotassic(fig.29C),andaverageinFe/Mgratio(fig.29D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Xgg Gneissic granite—Medium-fine-tofine-grained,equigranularbiotitegranitehavingexaggeratedflowfoliation.PresentinsmallbodiesfromnorthofMartinMountaintonorthofLimestonePeakinwesternpartofmaparea.MegascopicallysimilarintexturetograniteofOrejanoBasin(unitXob).

Limiteddatasuggestthatgraniteisalkali-calcic(fig.29A),mildlyperaluminous(fig.29B),averagetopotassic(fig.29C),andveryMgrichtoaverageinFe/Mgratio(fig.29D).PresumedtobeEarlyProterozoic

Xcb Crazy Basin Granite—Medium-tocoarse-grained,equigranulartoporphyriticbiotite-muscovitegranite(AndersonandBlacet,1972b,c).RedescribedhereinfromCrazyBasinQuartzMonzonite(AndersonandBlacet,1972c),basedonchemicalcomposi-tion.LargeplutonexposedfromsouthofCleatortopastsouthernboundaryofmaparea.CutsHumbugCreekGranodiorite(unitXhc).Insoutherntwo-thirdsofoutcrop,themedium-fine-grainedgranitehasastronglydevelopedflowfoliationthatparal-lelsmetawacke(unitXw)andmetapelite(unitXp).SouthernBradshawMountains


migmatitecomplexofAnderson(1989b)equivalenttosoutherntwo-thirdsofgranite.Innorthernone-thirdofoutcrop,medium-tocoarse-grainedgraniteisundeformedtomildlydeformedandhasdomedthemetawackeandmetapelite(Blacet,1985).Linear,north-southoutcroppatternofmetasedimentaryandmetavolcanicrocksoneastsideofplutonrelatedtodiapiricriseandupliftofplutonfollowingemplacement.Thebeltofmetavolcanicandmetasedimentaryrocksisnothereininterpretedasacrustalboundary(Leightyandothers,1991).Residualgravitycontourscross-cutcontactofCrazyBasinGranitewithwacke(Leightyandothers,1991),suggestingthatsouthernpartofCrazyBasinGranitemayoverhangnortheast-strikingmetavolcanicandmetasedimentaryrocksatdepthandberootless.

Plutonismoremafictosouth,butallisalkali-calcic(fig.32A),mildlytostronglyperaluminous(fig.32B),sodictoaverageinK/Naratio(fig.32C),andrangeswidelyinFe/Mgratio(fig.32D).MostmaficrocksareveryMgrichandmostfelsicrocksareveryFerich.

Age1,695Ma(S.A.Bowring,unpub.U-Pbzircondata,citedinKarlstromandothers,1987).40Ar/39Armuscoviteandbiotitedatesof1,410and1,412MasuggestMiddleProterozoicthermalpulseorprotractedcooling(HodgesandBowring,1995)

Xhm Granite of Horse Mountain—Medium-tocoarse-grainedleucocraticgraniteandpegmatite.ExposedonandnearHorseMountain,northofMinnehaha.Notacoher-entplutonicbody,butanextensiveswarmofgraniteandpegmatitedikesthatcutmaficmetavolcanicrocks.RockspreviouslyreferredtoasgraniteofHorseMountain(Ander-son,1989b)werethoughttobeequivalenttoHassayampaGranodiorite(unitXhy).CutsMinnehahaGranodiorite(unitXmh)andHassayampaGranodiorite.

Graniteisalkali-calcictocalc-alkalic(fig.32A),mildlytostronglyperaluminous(fig.32B),sodictopotassic(fig.32C),andaverageinFe/Mgratio(fig.32D).

SmallbodyonHorseMountainhasU-Pbzirconageofabout1,680Ma(S.A.Bowring,unpub.U-Pbzircondata,citedinHodgesandBowring,1995)

Xtc Granite of Tucker Canyon—Medium-grained,foliatedmuscovitegranite.ExposedalongTuckerCanyon,nearmouthofPartridgeCreekandBigChinoValley.

Graniteisalkali-calcic(fig.29A),stronglyperaluminous(fig.29B),averageinK/Naratio(fig.29C),andpredominantlyMgrich(fig.29D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994)

Xgr Granitic rocks, undivided—Medium-tomedium-coarse-grained,equigranulartoslightlyporphyriticbiotitegranite.Presentinsmallbodiesinwestern,northwestern,andsouth-easternpartsofmaparea.Slightlydeformedinzonesofhighstrainthatstrikenortheastanddipsteeply.PresumedtobeEarlyProterozoic

Alkali granitic rocks—Felsicintrusiverocks,primarilymuscovitebearing.Formspegma-titeswarmswithinpeliticmetasedimentaryrocksinzones1and2,adeformedplutonincentralBradshawMountains(zone3),andalargeplutoninzone6thatextendstonearPayson.Discussedfrommostmafictomostfelsic

Xcc Crooks Canyon Granite—Mainphaseconsistsofmedium-tomedium-coarse-grained,equigranularleucocraticbiotitegranite,originallynamedCrooksCanyonGranodiorite(AndersonandBlacet,1972a).ExposedincentralBradshawMountains,fromWalkeronthenorthtoneartheBodiemineonthesouth.Moderatelytostronglydeformedinmostoutcrops.StronglytectonizedalongChaparralshearzone(BerghandKarlstrom,1992),hereinshownasChaparralhigh-strainzone.Redescribedhereinbasedonchemi-calcomposition.

Graniteisalkali-calcic(fig.31A),butsomesamplesarecalc-alkalicbecauseoffractionalcrystallizationofparentmaterial.Graniteispredominantlymildlyperalumi-nous(fig.31B),verysodictosodic(fig.31C),andaveragetoveryFerich(fig.31D).

Ageabout1,730Ma(S.A.Bowring,unpub.U-Pbzircondata,citedinKarl-stromandBowring,1991).Ifleucogranite(unitXlg)thatcutsTexasGulchFormation(Blacet,1985)isequivalenttoCrooksCanyonGranite,ageofCrooksCanyonGranitemustbeyoungerthan1,720Ma

Xcca Aplite of Crooks Canyon Granite—Fine-grained,equigranularleucocraticbiotitegranodioritetoalaskite(Krieger,1965).ExposedpredominantlynorthofChaparral


high-strainzone.Undeformedinfarnorthernexposures,butmorestronglydeformednearChaparralhigh-strainzone.CutsmainphaseofCrooksCanyonGranite(unitXcc)andGovernmentCanyonTonalite(unitXgc).

Alkaligraniteisalkali-calcic(fig.31A),mildlytostronglyperaluminous(fig.31B),verysodic(fig.31C),andaveragetoveryFerich(fig.31D).Ageundetermined,butEarlyProterozoicagepresumedonbasisofchemicalsimilaritytoCrooksCanyonGranite

Xap Aplite-pegmatite of Tonto Mountain—White,medium-tocoarse-grainedapliteandpeg-matite.ExposedinbeltthatextendsfromwestsideofSullivanButtestopastCornfieldMountaininwesternpartofmaparea.Notacoherentplutonicbody,butamassofaplite-pegmatitedikes.Extensivelyintrudespeliticmetapelite(unitXp)andmetawacke(unitXw)eastofTuckerandalongTontoWash.CutsCornfieldMountainGranite(newlynamedunitXcf).

Apliteandpegmatitearealkali-calcic(fig.29A),stronglyperaluminous(fig.29B),verysodictopotassic(fig.29C),andveryMgrichtoMgrich(fig.29D).EarlyProterozoicagedeterminedfromPb-Pbwholerockisotopiccomposition(Bryantandothers,1994),butsomeaplite-pegmatitebodiesnearTuckercouldbeyounger

Xkw Alaskite of King Well—Red,medium-tofine-grainedalkaligranite(Krieger,1965).ExposedonlynearKingWell,eastofPaulden,andsouthofVerdeRiver.CutsPrescottGranodiorite(unitXpr).Possiblyrelated,inage,toRedRock(?)RhyoliteofSilverandothers(1986).

Limiteddatasuggestalkaligraniteisalkali-calcic(fig.30A),mildlyperalumi-nous(fig.30B),averageinK/Naratio(fig.30C),andveryFerich(fig.30D).PresumedtobeEarlyProterozoic

Xbn Granite of Bloody Basin—Medium-tocoarse-grained,undeformed,equigranulartoporphyriticleucocraticbiotitegranite.IncludedinVerdeRiverredgranitebatholithofAnderson(1989b).ExposedalongSkeletonRidgeinfarsoutheasternpartofmaparea,andalongVerdeRimfarthertothesouthwest.

Alkaligranitetograniteispredominantlyalkali-calcic(fig.34A),mildlyper-aluminous(fig.34B),verysodictosodic(fig.34C),andveryFerich(fig.34D).Ageundeterminedbutpresumedtobeabout1,700Ma,becauseofchemicalsimilaritytobothPaysonGranite(EdDeWitt,unpub.data,1998)andEarlyProterozoicmetarhyolitebeneaththeMazatzalPeakFormation(unitXmp)

Xlg Leucogranite—White,fine-tomedium-grainedleucocraticalkaligranite.Infarwest-ernpartofmaparea,exposedfromIndianHillonthenorthtoYoungMountainonthesouth.AlsoexposednearCopperBasin,westofPrescott.Texturallydistinctfromaplite-pegmatite(unitXap)byvirtueofitsequigranularnature.Undeformedinmostfarwesternexposures.DeformednearCopperBasin.

LeucogranitedikesthatcutTexasGulchFormationwestofBradyButteareporphyritic,containingphenocrystsofalbite,andfoliated(Blacet,1985).ThesedikescouldbepartoftheCrooksCanyonGranite(unitXcc).

Compositionofwesternleucograniteisanalkaligranitetogranitethatisalkali-calcic(fig.29A),stronglyperaluminous(fig.29B),verysodictopotassic(fig.29C),andaverageinFe/Mgratio(fig.29D).PresumedtobeEarlyProterozoic

EARLY PROTEROZOIC METASEDIMENTARY ROCKS

Xmp Mazatzal Peak Formation—Reddish-purplequartzite,conglomerate,andminorargillite.ExposedeastofDelRioSprings,northeastoftownofChinoValley.Minimumthick-nessabout1,200m.Ageofupperpartofsectionsuggestedtobelessthan1,650Ma(Chamberlainandothers,1991),butdocumentationforageisminimal.MazatzalPeakFormationinmapareamaybeslightlyyoungerthanintypeareaofMazatzalMountainstotheeast,wherebaseofsectionis1,700Ma(Silverandothers,1986;Coxandothers,2002)


Texas Gulch FormationXtgr Rhyolitic meta-tuffaceous rocks—Tanrhyoliticmetatuffandinterbeddedphyllite.

ExposednorthofDewey.Thicknessundetermined.Ageabout1,715Maandyounger(S.A.Bowring,unpub.U-Pbzircondata,citedinKarlstromandBowring,1991)

Xtgs Purple slate—Metamorphosedpurpleshaleandfine-grainedtuffaceousmetasedimentaryrocks.ExposednorthofDewey.Interbeddedwithrhyoliticmeta-tuffaceousrocks(unitXtgr)onaregionalscale.Thicknessundetermined

Xtgq Quartzose metasedimentary rocks—Metamorphosedsiltstone,tuff,sandstone,andminorrhyolite.ExposedaroundBradyButteGranodiorite(unitXbb)insouth-centralpartofmapareaandnorthofRoundHillinzone5B.Conglomeraticrocksrestuncon-formablyonandesiticintrusiverocks(unitXa3)southofRoundHill.Thicknessasmuchas300m

Xtgc Conglomerate—Metamorphosedpebbletocobbleconglomerate,sandstone,andarkose.Clastsofiron-formation,veinquartz,andBradyButteGranodiorite(unitXbb)com-mon.Thicknessofindividualbeds,tensofmeters.ExposedaroundBradyButteGranodiorite.ConglomeratebedsrestunconformablyonBradyButteGranodiorite(Blacet,1966).Multiplydeformedonalocalscale(O’Haraandothers,1978;Karl-stromandO’Hara,1984)whereS

2foliationsurfaceswitchesfrompredominantlywest

dippingtolocallyeastdippingXp Pelitic metasedimentary rocks—Metamorphosedsiltstone,sandyshale,andminorwacke.

ExposedaroundwesternpartofCrazyBasinGranite(unitXcb),nearCleator.Bedsofpeliticmetasedimentaryrocks,toothintoshowatmapscale,areinterbeddedwithwacke(unitXw).NorthofCleator,protolithsaremetamorphosedtoquartz-feldspar-muscovite-biotiteschist.SouthofCleator,andaroundCrazyBasinGranite,protolithsmetamorphosedtoquartz-muscovite-biotite-andalusite-stauroliteschist(DeWitt,1976;Blacet,1985;Argenbright,1986).SillimanitelocallydevelopedadjacenttoCrazyBasinGranite.Thicknessdifficulttoestimatebecauseofisoclinalfolding,butprob-ablyinkilometers.DerivedfromweatheringofEarlyProterozoicvolcanicandplutonicrocksofcentralArizonaprovince(WoodenandDeWitt,1991),asshownbylowTh/UratiosandPbisotopiccompositionsthathavelow207Pb/204Pbratios.Shale-normalizedREEpatternshavemoderatepositiveEuanomaly(Coxandothers,1991;thisstudy).

SimilarrocksexposednortheastofGraniteMountainandnorthofSkullValley.EastofTontoWash,protolithsmetamorphosedtoquartz-feldspar-muscovite-biotiteschist.WestofTontoWash,protolithsmetamorphosedtoquartz-muscovite-biotite-sil-limaniteschist.DerivedfromweatheringofEarlyProterozoicvolcanicandplutonicrocksofMojaveprovince(WoodenandDeWitt,1991),asshownbyhighTh/UratiosandPbisotopiccompositionsthathavehigh207Pb/204Pbratios.Shale-normalizedREEpatternshavesmallnegativeEuanomaly.Thicknessdifficulttoestimatebecauseoffolding,butprobablyinkilometers.Ageofbothsequencesabout1,725–1,740Ma

Xw Wacke—Metamorphosedwacke,sandstone,siltstone,andminorshale.Exposedextens-ivelyaroundnorthernandeasternpartsofCrazyBasinGranite(unitXcb),nearCleator.Changesfaciestothenorth,pastMayer,toincludetuffaceousrockseastofBlueBellmine.NortheastofMayer,facieschangeistopredominantlytuffaceousrocks.NorthofCleator,protolithsmetamorphosedtoquartz-feldspar-biotiteschist.SouthofCleator,andaroundCrazyBasinGranite,protolithsmetamorphosedtoquartz-muscovite-biotite-andalusiteschist.Thicknessdifficulttoestimatebecauseofisoclinalfolding,butprobablyinkilometers.DerivedfromweatheringofEarlyProterozoicvolcanicandplu-tonicrocksofcentralArizonaprovince(WoodenandDeWitt,1991),asshownbylowTh/UratiosandPbisotopiccompositionsthathavelow207Pb/204Pbratios.CrudepatternofincreasingAl

2O

3withdecreasingSiO

2shownbysamplesfromeastofBlueBellmine

tothesouthofCleator(AndersonandBlacet,1972b).Shale-normalizedREEpatternshavemoderatepositiveEuanomaly(Coxandothers,1991;thisstudy).

SimilarrocksexposednortheastofGraniteMountainandnorthofSkullValley.EastofTontoWash,protolithsmetamorphosedtoquartz-feldspar-biotiteschist.WestofTontoWash,protolithsmetamorphosedtoquartz-muscovite-biotiteschist.DerivedfromweatheringofEarlyProterozoicvolcanicandplutonicrocksofMojaveprovince


(WoodenandDeWitt,1991),asshownbyhighTh/UratiosandPbisotopiccomposi-tionsthathavehigh207Pb/204Pbratios.Shale-normalizedREEpatternshavesmallnegativeEuanomaly.Thicknessdifficulttoestimatebecauseoffolding,butprobablyinkilometers.Ageofbothsequencesabout1,725–1,740Ma

Xs Other metasedimentary rocks—Metamorphosedwacke,siltstone,peliticrocks,andminortuff.Exposedinfarwesternpartofmaparea,southofStinsonMountain;southofMt.TritleandLookoutMountain;andinfarsouthernpartofmaparea,onSilverMountain.Thicknessnotdetermined

Xwp Wacke and pegmatite—Metamorphosedwacke,sandstone,andsiltstone(unitXw)cutbygraniteandpegmatitebodiesrelatedtoCrazyBasinGranite(unitXcb).ExposedincoreofCrazyBasinGranite,southofHorsethiefBasin.Wackeprotolithsmetamor-phosedtoquartz-feldspar-biotite-andalusiteschist.Thicknessnotdetermined

Xpa Pelitic sedimentary rocks and aplite-pegmatite—Metamorphosedsiltstone,sandyshale,andminorwacke(unitXp)cutbyapliteandpegmatitebodiesrelatedtoaplite-pegma-tite(unitXap).ExposednearTucker,northofGraniteMountain.Peliticprotolithsmetamorphosedtoquartz-muscovite-andalusiteschist.Thicknessnotdetermined

Xwa Wacke and meta-andesite—Metamorphosedwacke(unitXw)andandesiteflowsandtuff.ExposedoneastsideofCrazyBasinGranite(Jerome,1956).Wackemetamorphosedtoquartz-feldspar-biotiteschist.Andesitemetamorphosedtofeldspar-actinolite-biotite-quartzschist.Andesiteflowsandtuffrepresenttheyoungestvolcanicepisodebeforewackeandpeliticsedimentaryrockscoveredthevolcanicedifices.ProbableequivalentrocksonwestsideofCrazyBasinGraniteincludemetabasaltflowsandgabbrosills.Thicknessofindividualandesiteflows,tensofmeters

EARLY PROTEROZOIC METAVOLCANIC ROCKS OF KNOWN CHEMICAL COMPOSITION

[ThecentralBradshawMountainsandtheBlackHillscontainextensiveexposuresofmetavolcanicrocksthatrangeincompositionfrombasalttorhyolite(AndersonandCreasey,1958;AndersonandBlacet,1972b;DeWitt,1979;Vance,1989;Anderson,1989a,b).Mappedunitsofthisstudyarebasedonchem-istry,notpublishednames,asthestructureandstratigraphyofpartsofthemetavolcanicrocksarepoorlyknown(DeWitt,1979;Anderson,1989b).Publishednamesarereferredtowherethevolcanicstratigraphyiswellknown.Descriptionsthatfollowdroptheprefix“meta-”whenreferringtorocktypeandchemistry. Stratifiedmetavolcanicandmetasedimentaryrocksinzones2and3AnorthoftheChaparralhigh-strainzonehadbeenreferredtoastheGreenGulchVolcanics(AndersonandBlacet,1972a,b).Ander-son(1989b)renamedrocksinthosezones,aswellasthoseinzones3Bandsomein4A,asbeingintheBradshawMountainsGroup.StratifiedrockssouthoftheChaparralshearzoneinzones4Aand4BwerereferredtoastheSpudMountainVolcanics(Andersonandothers,1971;AndersonandBlacet,1972a,b).Anderson(1989)renamedrocksinthosezones,aswellasthoseinthewesternpartofzone4C,asbeingintheMayerGroup.TheIronKingVolcanics(AndersonandBlacet,1972a,c)inzone4CareincludedbyAnderson(1989b)intheMayerGroup.Stratifiedrocksinzones5Aand5B,aswellasthoseintheeasternpartofzone4C,werereferredtoastheSpudMountainVolcanics(AndersonandBlacet,1972c).Anderson(1989b)renamedrocksinzones5Aand5BasbeingintheBlackCanyonCreekGroup.Nomenclatureofstratifiedrocksinzones6Aand6BremainsmuchasproposedbyAndersonandCreasey(1967)asbeingintheAshCreekGroup. Someofthemetavolcanicrocksarehydrothermallyaltered,especiallythoseassociatedwithvolca-nogenicmassivedeposits(O’Hara,1987a;VanceandCondie,1987;Lindberg,1989;DeWitt,1995).Manyofthefelsicmetavolcanicrocksarealteredtosuchanextentthatmajor-elementclassificationsofthemarenotpossible,androcknames(Vance,1989)havebeenappliedbasedonminor-elementgeochemistry,especiallythosenamesdevisedbyWinchesterandFloyd(1977),amongothers.Weutilizebothmajor-andminor-elementclassificationsinthisreportinordertoshowboththeunalteredprotolithandthetypeofalterationaffectingthemetavolcanicrocks. Maficmetavolcanicrockshavebeensampledmoreextensivelythanfelsicmetavolcanicrocksbecauseofthehydrothermalalterationdiscussedinthepreceding.Asaresult,thesummarygeochemicaldiagrams(figs.35and36)shouldnotbeusedtocalculatepercentagesofexposedrocktypes. IntheBradshawMountains(zones1–5),calcictocalc-alkalicbasalttobasalticandesiteisthemostwidespreadmetavolcanicrock(fig.35A).Alkalicmaficrocksarenotpresent.Muchofthebasalttobasalticandesiteissodictoverysodic(fig.35C)andaveragetoveryFerich(fig.35D).Maficsamples


Figure 35. Major-element classification summary diagrams for Early Proterozoic metavolcanic rocks in zones 1–5 in Bradshaw Moun-tains. Data from this study, Vance (1989), Anderson and Blacet (1972b), Anderson (1972), and Krieger (1965). Data from Vance (1989) in red triangles. Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

0.4

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1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-AlkalicAlkali-CalcicAlkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

2 2

EXPLANATION

Vance (1989)All other sources


Figure 36. Major-element classification summary diagrams for Early Proterozoic metavolcanic rocks in zone 6 in the Black Hills. Data from this study, Vance (1989), and Anderson and Creasey (1958). Data from Vance (1989) in red triangles. Rock abbreviations and field boundaries defined in figure 2. Red arrow indicates point lies outside of plot, in direction indicated.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


0

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

EXPLANATION

Vance (1989)All other sources


thatplotasalkali-calcichavelargelybeenaffectedbysodicalteration.Sampledrocksthatareintermedi-ateincomposition(andesitetodacite)arelessabundant.Sampledfelsicmetavolcanicrocksarecommonlyrhyodacitetorhyolite(fig.35A;rhyoliticrocksnotshown)thatrangesfromverysodictoaverage(fig.35C)andthatisaveragetoFerich(fig.35D).VeryMg-richrocksarenearlylacking. IntheBlackHills(zone6),thecompositionsofmetavolcanicrocksaredifferentfromthoseintheBradshawMountains.Basaltsarenearlylacking;andesiticbasaltsareminor(fig.36A).Andesiteanddaciteareabundantandarecalc-alkalictoalkali-calcic(fig.36A),verysodic(fig.36C),andveryFerich(fig.36D).Rhyodaciteandrhyolitearethemostabundantrocktypesandarelargelyalkali-calcictocalc-alkalic(fig.36A),verysodic(fig.36C),andaveragetoveryFerich(fig.36D).PotassicandverypotassicrocksandMg-richandveryMg-richrocksarelacking. ThesechemicaldifferencessupporttheinterpretationthatthemetavolcanicrocksintheBlackHillsaredistinctfromthoseintheBradshawMountains(Andersonandothers,1971;Anderson,1989b)andprobablywererelatedtoseparatevolcaniccenters.Agerangeofthemetavolcanicrocksisprobably1,740–1,765Ma(Andersonandothers,1971;Bowringandothers,1986;Karlstromandothers,1987).Thicknessesofvariousvolcanicunitschangerapidlyawayfromvolcaniccenters,makinganestimateofthetotalthicknessdifficulttoassess,butareundoubtedlyinmultiplekilometers.Discussedfrommostmafictomostfelsic,andportrayedinchemicaldiagramsfromwest(zone1)toeast(zone6)(figs.37–48). Volcanictexturesarepreservedinallmetavolcanicrocksthatarebelowmiddleamphibolitefacies.AlloftherocksintheBlackHillsarelessfoliatedandlessrecrystallizedthanthoseintheBradshawMoun-tains.MetamorphicgradedoesnotexceedgreenschistfaciesintheBlackHills(AndersonandCreasey,1958;Gustin,1988,1990).InthenorthernandcentralBradshawMountains,metavolcanicrocksareatgreenschistfacies(AndersonandBlacet,1972b;O’Hara,1980).ManyrockssouthofanapproximatelinefromCleatortoWalnutGrove,andaroundtheCrazyBasinGranite,areatamphibolitefacies,andsomevolcanictextureshavebeenobliterated(DeWitt,1976;O’Hara,1980).Localareasofgreenschist-faciesrocksarepreservednearSilverMountainnearsouthedgeofmaparea. Volcanicflowshaveunitsymbolsthatindicatetheircomposition(Xbforbasalt).Brecciashaveaunitsymbolthatindicatestheircompositionandanumericalsuffixthatshowstheirbrecciatednature(Xa1forandesiticbreccia).Tuffaceousunitssimilarlyhaveasuffixof2(Xd2fordacitictuff).Intrusivevolca-nicunitshaveasuffixof3(Xr3forrhyolitictuff).Agglomeraticvolcanicunitshaveanumericalsuffixof4(Xb4forbasaltictuff)]

Xb Basaltic flows—Fine-tomedium-grainedmetamorphosedtholeiite,basalt,andminorultra-maficrocks.Includessomebasalticandesitewhereflowsareinterbeddedwiththoleiiteandbasalt.Maficphenocrystsminor,butwherepresentareconvertedtoamphiboleandopaqueoxideminerals.Plagioclasephenocrystsminor,butpresentinmetabasaltatheadofMundsDraw(zone6).Exposedinzones2through5;minorbasaltinsouthernpartofzone6.

Inzone2,flowsareexposednorthofKirkland,westandnorthofGraniteMoun-tain,inSugarloafMountainarea,andinareafromMaverickMountaintoMountTritle.Flowsinzone2arepredominantlycalcictocalc-alkalictholeiite,basalt,andbasalticandesite(fig.37A)thatareverysodictoaverageinK/Naratio(fig.37C)andaveragetoveryFerich(fig.37D).Someandesiteispresent.Flatchondrite-normalizedREEpat-ternsindicatethatflowsinzone2areamongthemostprimitiveinBradshawMountains(EdDeWitt,unpub.data,2002).

Zone3AcontainsabundantflowsfromsouthofSpruceMountaintoCharcoalGulch.FromBigelowPeaktonorthofWalker,flowsaremostlycalc-alkalicandesiticbasalt(fig.38A).BigelowPeakareacontainssomeofthemostMg-richtholeiiteinBradshawMountains(fig.38D).Allflowshavechondrite-normalizedREEpatternsthathaveaslightlight-rare-earth-element(LREE)enrichmentandaminornegativeEuanomaly(Vance,1989;thisstudy).

Zone4AcontainsabundantflowsfromTowersMountaintothenortherncontactoftheMinnehahaGranodiorite(newlynamedunitXmh).

Flowsandbrecciasinzones4Band4CextendfromsouthofHumboldtareaonthenorthtoSilverMountainonthesouth.FlowswestoftheIronKingmine,extendingfromSpudMountaintopasttheMcCabeminealongGalenaGulch,arelargelycalc-alkalictocalcicbasalticandesite(fig.41A)thataresodictoaverageinK/Naratio(fig.



Figure 37. Major-element classification diagrams for unaltered Early Proterozoic metavolcanic rocks (units Xb and Xab) from zone 2 in Bradshaw Mountains. Data from this study. Rock abbreviations and field boundaries defined in figure 2. Location in parentheses is nearest named feature on map to listed locality.

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2 (w

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erce

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SiO

2 (w

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erce

nt)

C

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500

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1500

2000

2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

2

High-Al rocks: Jerome CanyonHigh-Ti rocks: none

KirklandJerome CanyonJersey Lily mine (Independent Spring)Little Copper CreekMaverick Mountain

EXPLANATION


Figure 38. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb, Xa, and Xd) from zone 3A in Bradshaw Mountains. Data from this study and Vance (1989). Rock abbreviations and field boundaries defined in figure 2. Rock names in brackets are those from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): Th, tholeiitic basalt; And-Bas, andesitic basalt; And, andesite.

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NK


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SiO2 (wt. percent)

60

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400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: noneHigh-Ti rocks: some at Potato Patch some north of Walker

(All other sources)Potato PatchLynx CreekNorth of WalkerNorth of Mt. Elliott

EXPLANATION

High-Al rocks: West of Potato Patch, sodicHigh-Ti rocks: none

(Vance, 1989)Bigelow Peak High-Mg [Th] Normal [Th, And-Bas, And] Sodic [Th, And-Bas, And]

West of Potato Patch [And-Bas]West of Potato Patch, sodic [And-Bas]

Figure 39. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb, Xba, Xa, and Xd) from zone 3B in Bradshaw Mountains. Data from this study and Anderson and Blacet (1972b). Rock abbreviations and field boundaries defined in figure 2. Location in parentheses is nearest named feature on map to listed locality.


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60

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2 (w

t. p

erce

nt)


D

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SiO

2 (w

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erce

nt)

C

2500200015001000

500

1000

1500

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2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: noneHigh-Ti rocks: none

Poland Tunnel (Postmaster Spring)North of Big Bug MesaSouthwest of Mount Union

EXPLANATION


Figure 40. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (unit Xd2) from zone 4A in Bradshaw Moun-tains. Data from this study, Anderson and Blacet (1972b), Blacet (1985), and Vance (1989). Rock abbreviations and field boundaries defined in figure 2. Location in parentheses is nearest named feature on map to listed locality. Rock name in brackets is from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): And, andesite. Red arrow indicates point lies outside of plot, in direction indicated.

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SiO2 (wt. percent)

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400.4 0.5 0.6 0.7 0.8 0.9

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2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

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2 (w

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erce

nt)

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500

1000

1500

2000

2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: noneHigh-Ti rocks: none

EXPLANATION

(All other sources)Goodwin (West of Battle Flat)

(Vance, 1989) Goodwin (West of Battle Flat) [And]


Figure 41. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb, Xab, and Xd, possibly Xrd) from zone 4B in Bradshaw Mountains. Data from this study, Anderson and Blacet (1972b), and Vance (1989). Rock abbreviations and field boundaries defined in figure 2. Location in parentheses is nearest named feature on map to listed locality. Rock names in brackets are those from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): And-Bas, andesitic basalt; Th, tholeiitic basalt; And, andesite.

60

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2 (w

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1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: McCabe, Huron, and HackberryHigh-Ti rocks: Iron King, moderate Ti-rocks west of Hackberry

(All other sources)McCabe mineIron King mineHuron mine (All near Humboldt)Humboldt

2

High-Al rocks: Spud Mountain flows, breccias, tuffHigh-Ti rocks: Spud Mountain flows, moderate-Ti in breccias

EXPLANATION

(Vance, 1989)Spud Mountain High-Ti flows [And-Bas] High-Al flows [Th] Andesitic flows [And] Moderate-Ti breccias [And-Bas] Normal breccias [Th, And-Bas] All tuffIron King High-Ti flows [And-Bas, And]


Figure 42. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb and Xa) from zone 4C in Bradshaw Mountains. Data from this study, Anderson and Blacet (1972b), Anderson (1972), Blacet (1985), Vrba (1980), and Vance (1989). Rock abbreviations and field boundaries defined in figure 2. Locations in parentheses are nearest named feature on map to listed mine or locality. Rock names in brackets are those from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): Th, tholeiitic basalt; And, andesite.

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: Blue BellHigh-Ti rocks: Blue Bell, DeSoto mine area, Swastika, and Silver Mountain

(All other sources)MayerBluebell mineDeSoto mine areaNorthwest of CleatorSwastika mine (north of Crown King)War Eagle mineOro Belle mine (both south of Crown King)Fort Misery (along Humbug Creek)Silver Mountain

2

High-Al rocks: noneHigh-Ti rocks: Blue Bell

(Vance, 1989)Blue Bell mine flows Normal [Th, And] Sodic [Th]

EXPLANATION


Figure 43. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb and Xa) from zone 5A in Bradshaw Mountains. Data from this study, Anderson (1972), and Vrba (1980). Rock abbreviations and field boundaries defined in figure 2.

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: Bland Hill, CordesHigh-Ti rocks: none

CordesTownsend ButteBland Hill

EXPLANATION


Figure 44. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb and Xa) from zone 5B in Bradshaw Mountains. Data from this study, Anderson and Blacet (1972b), and Vance (1989). Rock abbreviations and field boundaries defined in figure 2. Locations in parentheses are nearest named feature on map to listed mine or locality.

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: Binghampton, Stoddard, Tri-metals minesHigh-Ti rocks: none

(All other sources)Southwest of Round HillCopper Queen mineTri-metals mine (north of Russian well)South of Round Hill

2

High-Al rocks: Yarber WashHigh-Ti rocks: none

(Vance, 1989) Yarber Wash (north of Russian well)

EXPLANATION


Figure 45. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xb and Xa) of intermediate to mafic composition from zone 6A in the Black Hills. Data from this study, Anderson and Creasey (1958), Wolfe (1983), and Vance (1989). Rock abbreviations and field boundaries defined in figure 2.

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: Munds DrawHigh-Ti rocks: none

Near Squaw Peak Squaw Creek Canyon Gap Creek Marlow Mesa Verde River

EXPLANATION

High-Al rocks: Squaw Creek Canyon, Gap Creek, Verde RiverHigh-Ti rocks: none

Munds DrawGrapevine GulchBrindle PupBurnt Canyon


Figure 46. Major-element classification diagrams for Early Proterozoic metavolcanic rocks of felsic to intermediate composition from zone 6A in the Black Hills and near Dugas. Data from this study, Anderson and Creasey (1958), and Vance (1989). Rock names in brack-ets are those from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): Th, tholeiite; And, andesite; Dac, dacite. A, R1R2 major-element classification diagram (De la Roche and others, 1980). T Bas, trachybasalt; Lat Bas, latitic basalt; And-Bas, andesitic basalt; T And, trachyandesite; Lat, latite; Lat And, lati-andesite; And, andesite; Tr, trachyte; Q Lat, quartz latite; Dac, dacite; Q Tr, quartz trachyte; Alk Rhy, alkali rhyolite; Rhy, rhyolite; R Dac, rhyodacite. Fields of alkalinity from Fridrich and others (1998). B–D, Field boundaries defined in figure 18.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

A

30002500200015001000

500

1000

1500

Calcic

Calc-AlkalicAlkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

High-Al rocks: Tule CanyonHigh-Ti rocks: none

Bishop CreekTule CanyonWillow Spring

(All other sources)Indian HillsGrapevine GulchBrindle PupBurnt Canyon

High-Al rocks: Brindle PupHigh-Ti rocks: some Burnt Canyon, Deception

(Vance, 1989)Grapevine Gulch [Th]Brindle Pup [And]Burnt Canyon dacite [And]Burnt Canyon, felsic [Dac]

EXPLANATION


Figure 47. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (unit Xa) of intermediate to mafic composi-tion from zone 6B in the Black Hills. Data from this study, Anderson and Creasey (1958), Vance (1989), and Gustin (1990). Rock abbrevia-tions and field boundaries defined in figure 2.

0.4

0.5

0.6

0.7

0.8

0.9

1.0

40 50 60

A/C

NK


B

SiO2 (wt. percent)

60

50

400.4 0.5 0.6 0.7 0.8 0.9

SiO

2 (w

t. p

erce

nt)


D

0 0.1 0.2 0.3 0.440

50

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

2500200015001000

500

1000

1500

2000

2500

Calcic

Calc-Alkalic

Alkali-Calcic

Alkalic

R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: noneHigh-Ti rocks: Shea

GaddesShea

EXPLANATION


Figure 48. Major-element classification diagrams for Early Proterozoic metavolcanic rocks (units Xa, Xd, Xrd, and Xr) of felsic to intermediate composition from zone 6B in the Black Hills. Data from this study, Anderson and Creasey (1958), Vance (1989), and Gustin (1990). Rock abbreviations defined in figure 46; field boundaries defined in figure 18. Rock names in brackets are those from Vance (1989), as based on minor-element classification scheme of Winchester and Floyd (1977): Dac, dacite; And, andesite; Bas-And, basaltic andesite; R Dac, rhyodacite.

60

500.5 0.6 0.7 0.8 0.9 1.0


SiO

2 (w

t. p

erce

nt)

D

0.7

0.8

0.9

1

1.1

1.2

1.3

50 60 70

A/C

NK


SiO2 (wt. percent)

B

60

500 0.2 0.4 0.6

K2O/K2O + Na2O

SiO

2 (w

t. p

erce

nt)

C

30002500200015001000

500

1000

1500

Calcic

Calc-Alkalic


R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

R2

= 60

00C

a +

2000

Mg

+ 10

00A

l

A

High-Al rocks: noneHigh-Ti rocks: SheaMod-Ti rocks: Buzzard

(All other sources)Quartz porphyryCleopatraDeceptionGaddesSheaBuzzard

High-Al rocks: GaddesHigh-Ti rocks: Shea

EXPLANATION

(Vance, 1989)Buzzard [Dac]Deception, Cleopatra member [R Dac, Dac]Deception, southGaddes [And, Dac]Shea [Bas-And]

41C)andveryFerich(fig.41D).Brecciabodiescontainedwithintheflowsalsoareandesiticbasaltthatrangesfromalkali-calcictocalcic(fig.41A)andthatareverysodictosodic(fig.41C)andveryFerich(fig.41D).Alltheseflows,exceptthosethatarehighTi,havechondrite-normalizedREEpatternsthathaveslightLREEenrichmentandlittletonoEuanomalies(Vance,1989;thisstudy).

SomeflowseastofIronKingminearecalc-alkalictoalkali-calcicandesiticbasalt,butmoreareandesitic(fig.41A).Andesiticbasaltisverysodic(fig.41C)andFerich(fig.41D),similartoflowsatSpudMountain.

FlowsatHuronmineandeastofHumboldtarecalcictholeiitetocalc-alkalicbasalt(fig.41A)thatisverysodic(fig.41C)andaveragetoveryFerich(fig.41D).Chondrite-normalizedREEpatternsoftheseflowsaresimilartothoseonSpudMountain.

Mostflowsinzone4Carecalc-alkalicbasalttocalcictholeiite(fig.42A)thatareverysodic(fig.42C)andMgrichtoveryFerich(fig.42D).REEpatternsofsuchrocksinnorthernandcentralpartsofzonehavetypicalLREEenrichmentandlittleornoEuanomaly(Vance,1989;thisstudy).Maficrocksinsouthernpartofzone,how-ever,haverelativelyflatREEpatterns,similartothoseofbasalticrocksinzone2.

Zones5Aand5Bcontainminorbasalt,principallyalongeastsideofCrazyBasinGranite,fromsoutheastofMayertosouthedgeofmaparea,andinYarberWasharea.InTownsendButteandBlandHillareas(zone5A),basalttotholeiiteismostcommon,butminorultramaficrocksarenoted(fig.43A).FlowsarepredominantlyverysodictoaverageinK/Naratio(fig.43C)andrangewidelyinFe/Mgratio(fig.43D).Calc-alkalicbasaltandcalcictholeiitearealsothemostcommonflowsinzone5B(fig.44A).FlowsnearcontactwithgranophyreofCherryareenrichedinpotassium(fig.44C).Mostflowsinzone5BareaverageinFe/Mgratio(fig.44D).FlowsnearCordesandBlandHillhavelowconcentrationsofREEandrelativelyflatchondrite-normalizedpatterns.

Theonlybasalticflowsinzone6AareatfarnorthwestendofBlackHills,nearheadofMundsDraw,andnorthofSquawPeak,alongsouthmarginofVerdeRivervalley.FlowsatMundsDrawaredistinctlyporphyritic,containingplagioclasepheno-crysts.Flowsarecalc-alkalicbasalttocalcictholeiite(fig.45A)thatissodictopotassic(fig.45C)andveryFerich(fig.45D).REEabundancesareamonglowestofallbasalts.Chondrite-normalizedpatternisflat.FlowsinSquawCreekCanyonarealkali-calcictocalc-alkalicbasalt(fig.45A)thatrangewidelyinK/Naratio(fig.45C)andareveryFerich(fig.45D)

Xb2 Basaltic tuff—Fine-tomedium-grained,metamorphosedbasaltictuff,basalt,andchemi-callyprecipitatedtuffaceousrocks.Exposedinzones2,3A,and4C.MasssouthofPrescott(zone2)ismixtureofbasaltictuffandtuffaceoussedimentaryrocks(Krieger,1965)andislargelyfeldspar-actinoliteschistandinterbeddedquartz-feldspar-biotiteschist.MasseseastofLynxCreekandnearheadofGreenGulch(zone3A)haveprotolithsimilartothatsouthofPrescott.LargemasssouthofMayerismixtureofthinbasaltflows,interflowmafictuff,andthinbodiesofiron-formationandchert.UnitprobablyextendsnorthofArizonahighway69.Metamorphosedtoactinolite-plagioclase-chloriteschist.MassnorthandsouthofCrownKing(zone4C)waspredominantlyafine-grainedcalcareousmafictuffthatcontainedthinbasaltflows(DeWitt,1976).Tuffmetamorphosedtodiopside-plagioclase-quartz-hornblende-gar-net-epidotecalc-silicaterock

Xb4 Basaltic agglomerate—Fine-tomedium-grained,metamorphosedbasaltmatrixandangulartosubroundedclastsofchert,andesite,basalt,minorrhyolite,andcalcareousrocks(DeWitt,1979;Blacet,1985).LargemassexposedeastofBlueBellmine(zone4C).Thickness500–900m.Matrixiscalc-alkalicbasalt(fig.42A)thatisverysodic(fig.42C)andMgrich(fig.42D).SmallermassesexposedatTri-metalsmine,northofRussianwell,andeastofRattlesnakeCanyon(zone5B).MatrixnearTri-metalsmineiscalc-alkalictocalcic(fig.44A),haslargerangeinK/Naratio(fig.44C),andisaver-agetoFerich(fig.44D).MatrixhaslowconcentrationofREEandflatchondrite-normalizedpattern(Vance,1989;thisstudy).Thickness20–50m


Xab Andesitic basalt flows—Fine-tomedium-grainedmetamorphosedandesiticbasaltandminorbasaltandandesite.Maficphenocrystsminor,butwherepresentareconvertedtoamphiboleandopaqueoxideminerals.Exposedinzones3,4,and5.Presentinzone2nearJerseyLilymine,butincludedwithinmoreextensivebodyofbasalt.

Zone3AcontainsabundantflowsfromsouthofSpruceMountaintoeastofLynxCreek.NorthofWalker,flowsarepredominantlycalc-alkalicbasalticandesiteandalkali-calcicandesiticbasalt(fig.38A).Sodicenrichment,orspilitization,hasaffectedmanyofthemaficrocks(Vance,1989).Suchspilitizedrockswouldplotbelowandtotheleftoftheirunalteredprotolithsonfigure38A.Evenunalteredrocksareverysodictosodic(fig.38C).AllflowsexceptoneatPotatoPatchhavechondrite-normal-izedREEpatternsthathaveaslightREEenrichmentandaminornegativeEuanomaly(Vance,1989;thisstudy).

OnelargemassofbasalticandesitenearCordesisaverageinK/Naratio(fig.43C)andFerich(fig.43D).Lati-basaltnearCordesisresultofspilitizationofandesiticbasalttobasalt(fig.43A)

Xab1 Andesitic basalt breccia—Fine-tomedium-grained,metamorphosedbasalticandesitematrixandangularclastsofandesiteandmorefelsicvolcanicrocks(AndersonandBlacet,1972b).ExposedinlargemassfromSpudMountainonthenorthtoBigBugMesaonthesouth.Flowswithinbrecciaarelargelycalc-alkalictocalcicbasalticandesite(fig.41A)thatissodictoaverageinK/Naratio(fig.41C)andveryFerich(fig.41D).Brecciafragmentswithinflowsalsoarebasalticandesitethatrangefromalkali-calcictocalcic(fig.41A)andthatareverysodictosodic(fig.41C)andveryFerich(fig.41D).Alltheseflows,exceptthosethatarehighTi,havechondrite-normalizedREEpatternsthathaveslightLREEenrichmentandlittletonoEuanomalies(Vance,1989;thisstudy)

Xa Andesitic flows—Fine-tomedium-grained,metamorphosedandesiteandminorandesiticbasaltanddacitecontainingalteredphenocrystsoffeldspar.Exposedinzones2,4,and5inBradshawMountainsandinzone6inBlackHillsandDugasareas.BodyalongSlateCreek(zone2)containssomebrecciafragments.AndesiticrocksalongLittleCopperCreekandnearPotatoPatchincludedinandesiticbasalt(unitXab).

Bodyinzone4BthatextendsfromIronKingmineonthenorthtoLittleBugMesaonthesouthispredominantlycalc-alkalictoalkali-calcicandesite(fig.41A)thatisverysodic(fig.41C)andFerichtoveryFerich(fig.41D).Alkali-calcicbasalticandesite(fig.41A)isinterbeddedwiththeandesite.Includedwiththisnormalandesiteareflowsofhigh-Tiandesitetolati-andesitethatareenrichedinREEandformchon-drite-normalizedpatternsthatslopegentlydownfromtheLREEtotheheavyrare-earth-element(HREE)andthathaveminortononegativeEuanomalies(Vance,1989;thisstudy).

Alargeareaofandesiteflows,tuffs,andinterbeddedchertandiron-formationcropsoutfromMayertoCrownKinginzone4C.AndesitefromneartheSwastikamineisrepresentativeoftheflows,whicharecalc-alkalic(fig.42A),verysodic(fig.42C),andveryFerich(fig.42D).SmallerareasofandesitearefoundeastofCordestoMayerinzone5A.

IntheBlackHills(zone6A),andesitesarenotedasbombswithintuffaceousrocksinGrapevineGulchFormationalongYaegerCanyon(Vance,1989).Bombsarecalc-alkalic(fig.46A),verysodictosodic(fig.46C),andveryFerich(fig.46D).

TheSheaBasalt(AndersonandCreasey,1967),whichcropsoutsouthofJeromeinzone6B,isadistinctivehigh-Tiandesitetolati-andesitethatisalkali-calcictocalc-alkalic(figs.47A,48A).TheShea,whichisverysodic(figs.47C,48C)andveryFerich(figs.47D,48D),iscutbygabbrosillsanddikestoosmalltobeshownatmapscale.LimiteddatafromalteredsamplesofdikesandsillssuggestanalkalicsyenogabbrotosyenodioriticcompositionthatisMgrich.GabbrosofthiscompositionareunknownfromEarlyProterozoicrocks(unitsXgb,Xlgb,Xdi)inmaparea,butarepresentinMiddleProterozoicgabbro(unitYgb).AgeneticrelationshipoftheSheatothegabbrobodiesispossible,butunprovenatpresent.


AlongSquawCreekCanyonandtothesouth,alongVerdeRiver(zone6A),calc-alkalictoalkali-calcicandesite(fig.45A)isexposedthatissodictoverypotassic(fig.45C)andaveragetoFerich(fig.45D)

Xa1 Andesitic breccia—Fine-tomedium-grained,metamorphosedandesiticmatrixandangu-larclastsofandesiteandmorefelsicvolcanicrocks(AndersonandBlacet,1972b,c).SmallbodynorthofMt.Elliottinzone3Ahasmatrixofcalcicandesitetodacite(fig.38A)thathasanaverageK/Naratio(fig.38C)andisaveragetoFerich(fig.38D).SmallbodiesofandesitebrecciaareexposedfromBigBugMesatowestofBradyButteinzones4Aand4B.Althoughrocksarealtered,theirminor-elementcomposi-tionindicatesanandesiticcomposition.AlargemassofandesiticbrecciaextendsfromeastofHumboldttonearCopperMountain,eastofMayer.Minor-elementchemistryofrockssuggestsabasalticandesitetoandesite.AndesiticbrecciainGrapevineGulchFormationexposednorthofShylockmineinzone6Ahasamatrixthatiscalc-alkalic(figs.45A,46A),predominantlyverysodictosodic(figs.45C,46C),andaveragetoveryFerich(figs.45D,46D)

Xa3 Andesitic intrusive rocks—Fine-grained,porphyriticintrusiverockorflowdomecontain-ingphenocrystsofplagioclaseandalteredmaficmineral.ExposedonlysouthofRoundHillinzone5B.Andesiteisalkali-calcic(fig.44A),sodic(fig.44C),andMgrich(fig.44D)

Xd Dacitic flows—Fine-grained,porphyriticdacitecontainingphenocrystsofplagioclase.FlowsandbrecciasexposedeastofClimaxmineinzone2andwestofLynxLakeinzone3.MinordaciteinterbeddedwithbasalticandesitebreccianorthofBigBugMesainzone4Biscalc-alkalic(fig.39A),verysodic(fig.39C),andveryFerich(fig.39D).DaciteinterbeddedwithbasaltandrhyoliteatBlueBellmine(zone4C)iscalcictocalc-alkalic(fig.42A),verysodic(fig.42C),andMgrich(fig.42D).AtCopperMoun-tain,inzone5A,dacitecompositionisinferredfromminor-elementchemistry.

FlowsinGrapevineGulchFormationinsouthernBlackHills(zone6A)rangefromcalcicdaciteorrhyodacitetocalc-alkalicandesite,andincludeminorrhyolite(fig.46A).Anaveragecompositionisdacite,butsomeflowsmayberhyodacite.AndesiteanddaciteorrhyodacitearesodictoaverageinK/Naratio(fig.46C)andveryFerich(fig.46D).

TheBrindlePupAndesiteisaseriesofvesicularflowsthathaveafine-grainedgroundmassandconspicuousplagioclasephenocrysts.Flowsrangeincompositionfromcalc-alkalicandesitetocalcicrhyodacite(fig.46A),andhaveanaveragecomposi-tionofdacite.Overall,flowsaremetaluminoustostronglyperaluminous(fig.46B),predominantlyverysodic(fig.46C),andpredominantlyFerichtoveryFerich(fig.46D)

Xd1 Dacitic breccia—Fine-grainedmatrixofslightlyporphyriticdacitecontainingplagioclasephenocrysts.Abundantclastsofdaciteandmorefelsicvolcanicfragments.ExposedaroundCopperMountain,eastofMayerinzone5B.Daciticcompositioninferredfromminor-elementchemistry

Xd2 Dacitic tuff—Fine-grainedmatrixandabundantfeldsparandquartzphenocrystsincrystal-richtuff.Containsvariableconcentrationsoffelsictointermediate-compositionclasts.Hasbothweldedandnonweldedcharacteristicswheremetamorphismhasnotdestroyedoriginaltextures.

LargestmassexposedwestofBattleFlat,onwestsideofBradyButteGrano-diorite,inzone4A.Containsabundantplagioclasephenocrystsandlesserpartiallyresorbedquartzphenocrysts(Blacet,1985).Lithicfragmentsmostlyofdacitictoandesiticcomposition.Probablyintertongueswithandesiticmaterialtothenorth.Compositionrangesfromcalcicrhyodacitetocalc-alkalicdacite(fig.40A)thatismetaluminoustoslightlyperaluminous(fig.40B),verysodictosodic(fig.40C),andveryMgrichtoaverageinFe/Mgratio(fig.40D).Mg-richnatureofdaciteisatypicalforunalteredrocksinBradshawMountainsandBlackHills,asmostrocksareaveragetoFerich(fig.35D).REEpatternhasflatHREEsegmentandslightlyenrichedLREEandminornegativeEuanomaly(Vance,1989;thisstudy).Major-andminor-element


chemistryofdacitecloselyresemblethatofMinnehahaGranodiorite(newlynamed),suggestingthatgranodioritemaybesubvolcanicequivalentofdacite.

SmallerbodiesexposednorthofChaparralfaultinzones3Aand4Bcontainfewerphenocrystsofplagioclaseandmorelithicfragments(Krieger,1965).Tuffinter-beddedwithbrecciabeds.

Crystal-andlithic-richtuffexposedalongTuleCanyon,eastofDugasinzone6A,retainsvariablecompactionandweldingtextures.Tuffisacalc-alkalicdacitetorhyodacite(fig.46A),andismoremafictowardthebase.Tuffismetaluminoustomildlyperaluminous(fig.46B),verysodic(fig.46C),andFerichtoveryFerich(fig.46D).

TuffaceousrocksinGrapevineGulchFormationinsoutheasternBlackHills(zone6A)containmixedsedimentaryunitsandcontainclastsofrhyolite,dacite,anddarkandesite.AlongYaegerCanyon,onwestsideofMingusMountain,tuffcontainsmaficlithicmaterialandhyaloclastite(Vance,1989)

Xd3 Dacitic intrusive rocks—Fine-grained,porphyritictoequigranulardacitecontainingphe-nocrystsofplagioclase.ExposedonlyinGrapevineGulchFormationinsoutheasternBlackHills(zone6A).Maygradeintoflows

Xrd Rhyodacitic flows—Fine-grained,porphyriticrhyodacitecontainingphenocrystsofquartzandfeldspar.Includesminorcrystal-richtuffandfragmentalrhyodacite.Exposedonlyinsmallbodiesinzones3Aand3BinBradshawMountains,butwidelyexposedinsouthernBlackHills,northofCherry.

SmallbodiesnearthePoland-WalkerTunnelandalongBigBugCreeknorthofBigBugMesaarecalc-alkalic(figs.39A,41A),predominantlyverysodic(fig.41C),andaveragetoFerich(figs.39D,41D).SimilarbodiesalongBenjaminGulchinzone3Aarepresumedtobecalc-alkalicrhyodacitethatisstronglyperaluminous,verysodic,andveryFerich.

InsouthernBlackHills,threemajorrockunitshaverhyodaciticcomposition.DaciteofBurntCanyoncontainsvesicularflowshavingafine-grainedgroundmassandphenocrystsofplagioclaseandfine-grainedquartz.Flowsrangefromalkali-calcicrhyodacitetocalc-alkalicrhyodacite(fig.46A),andaremetaluminoustomildlyperalu-minous(fig.46B),verysodic(fig.46C),andFerichtoveryFerich(fig.46D).Relictphenocrystassemblagemayindicateanoverallandesiticcomposition(Vance,1989).FelsicpartsofBurntCanyonflowsarecalcicrhyodacite(fig.46A),stronglyperalumi-nous(fig.46B),verysodic(fig.46C),andpredominantlyaverageinFe/Mgratio(fig.46D).Similarly,relictphenocrystassemblagemayindicateanoverallandesiticcompo-sition(Vance,1989).

TheDeceptionRhyolitesouthofBrindlePupminehasafine-grainedtoapha-niticgroundmassandphenocrystsofplagioclaseandquartz.Limitedsamplessuggestthatflowsarecalc-alkalicrhyodacite(fig.48A)thatisstronglyperaluminous(fig.48B),verysodic(fig.48C),andaverageinFe/Mgratio(fig.48D).Thisrhyodaciticcomposi-tionisslightlymoremaficthanthatofleastalteredrocksintheDeception(?)RhyolitenearJerome.

RocksmappedasGaddesBasaltareveryheterogeneousandcontainlittletonobasalt.Majorrocktypesconsistoffine-grained,darkrhyodacite,dacite,spilitizedandesite,andveryminorbasalt.Mostsampledunitsarecalc-alkalictocalcicrhyoda-cite(fig.48A)thatismetaluminous(fig.48B),verysodic(fig.48C),andFerichtoveryFerich(fig.48D).

RhyodaciteflowsareexposedonMarlowMesaandalongGapCreekinzone6A.Flowsarecalc-alkalicrhyodacite(fig.45A)thatismildlyperaluminous(fig.45B),hasawiderangeinK/Naratio(fig.45C),andisaveragetoveryFerich(fig.45D).

AgeofDeceptionRhyolitenearJeromewassuggestedtobeabout1,770Ma(Andersonandothers,1971),butthatagewasquestionedbyL.T.SilverinConwayandKarlstrom(1986).Ageofabout1,740Ma(S.A.Bowring,unpub.U-PbzircondatacitedinKarlstromandBowring,1991)maybemoreaccurate

Xr Rhyolitic flows and pyroclastic rocks—Fine-grained,porphyriticrhyolitecontainingphe-nocrystsofquartzandminorfeldspar.Includessmallbodiesofbrecciaandtuff,aswell


assilicifiedandveinedrhyolitethatisnotincludedinthehydrothermallyalteredrhyo-literelatedtomassivesulfidemineralization(unitXrh).Someflowshaveextensivelybrecciatedflowtopsandmargins,andaredifficulttodistinguishfrombodiesofbreccia.Exposedthroughoutzones1through6.Particularlyabundantinzone5AalongeasternmarginofCrazyBasinGraniteandinzone6BinsouthernBlackHills.

FlowsandminortuffeastofClimaxmineinzone2areinterbeddedwithdaciteandmoremaficrocks.BodiesnorthofSpruceMountaininzone3Aaremostlyflows,butincludesomehypabyssalintrusivemassesthatcutbasalticandesite.Limiteddatasuggestthatflowsandhypabyssalbodiesarecalc-alkalicrhyolitetorhyodacitethatismildlyperaluminous,verysodic,andMgrich.

ThinflowsandminorbodiesoftuffnorthofChaparralhigh-strainzoneandnearLynxCreekinzone3Arangefromcalcicrhyolitetorhyodacitethatisstronglyperalu-minous,verysodic,andveryMgrichtoalkali-calcicrhyolitethatismildlyperalumi-nous,verysodic,andFerich(Vance,1989;thisstudy).

SouthofChaparralhigh-strainzone,alongBigBugCreek,inzone4B,bodiesofrhyoliteareinterbeddedwithrhyodaciteandminortuff.Leastalteredbodiesofrhyoliterangeincompositionfromcalcicrhyodacitetoalkali-calcicrhyolitethatismildlyper-aluminous,rangeswidelyinK/Naratio,andisaveragetoFerich(Vance,1989).NorthofBigBugCreek,nearMt.Elliott,limiteddatasuggestpresenceofalkali-calcicrhyo-litetoalkalirhyolitethatismildlyperaluminous,averageinK/Naratio,andFerich.

Largebodiesofrhyolite,breccia,andtuffareexposedfromnorthofCrownKingstocktosoutheastofHumboldtinzone4C.Thelargestbodies,nearDeSotomineandsoutheastofRoundHill,aresilicified.LimiteddatafromsmallerbodiesnorthandwestofMayersuggestrhyoliteisalkali-calcic,mildlyperaluminous,sodic,andaverageinFe/Mgratio.

Largestconcentrationofrhyoliteflows,tuffs,andvariablysilicifiedrhyoliteinmapareaisalongBlackCanyonandwithintheBlackCanyonhigh-strainzone,fromnearCordestopastsouthernboundaryofmaparea(Jerome,1956;AndersonandBlacet,1972c).Silicificationandlossofalkalimetalsmakeoriginalcompositionofrhyolitesdifficulttoascertain.

BodiesofrhyolitenearCordesinzone5Aarefine-grainedflowsinterbeddedwithandesiteandbasalticandesite.Rhyoliteiscalc-alkalic,mildlyperaluminous,verysodic,andaveragetoFerich.NumerousbodiesofrhyolitefromsoutheastofRoundHilltowestofYarberWashinzone5Brangefromflowstohypabyssalintrusivemasses.Dataaretoolimitedtoassessthechemistryoftheserhyolitebodies.

Fine-grainedtoaphaniticflowsandhypabyssalbodiesareinterbeddedwithtuffwestofnorthernBlackHills,alongCoyoteWash(zone6A).Limiteddatasuggestthathigh-silicarhyoliteiscalc-alkalic,mildlyperaluminous,verysodic,andFerich.

PorphyriticrhyolitecontainingquartzandminorplagioclasephenocrystsatWil-lowSpring,eastofDugasinzone6A,isalkali-calcic(fig.46A),mildlyperaluminous(fig.46B),verysodic(fig.46C),andaveragetoveryFerich(fig.46D).

TheBuzzardRhyoliteinsouthernBlackHills(zone6B)isaflow-bandedrockthatcontainsphenocrystsofplagioclaseandquartz.Fragmentsoffelsicvolcanicsarecommoninrhyolite,andbrecciabedsthatlackmatrixmaterialarenoted(AndersonandCreasey,1958).Thishigh-silicarhyoliterangesfromcalcictoalkali-calcic(fig.48A)andismildlytostronglyperaluminous(fig.48B),verysodic(fig.48C),andMgrichtoFerich(fig.48D).

CleopatraFormation(previouslyreferredtoasCleopatraQuartzPorphyry)andDeceptionRhyoliteatJeromearesuggestedtobeasoldas1.76Ga(Andersonandothers,1971).Newerdeterminationof1,738±0.5Ma(S.A.Bowring,supplementarydatainSlackandothers,2007)ispreferredageofrhyolite

Xr1 Rhyolitic breccia—Fine-grainedtoaphaniticrhyolitebrecciaandquartz-veinedrhyolite.ExposednorthofBlueBellmineinzone4C.OtherbrecciabodiestoosmalltobeshownatmapscaleareatDeSotomine,inzone4C;southwestofRoundHill,inzone4C;atCopperQueenmine,tothesoutheastofRoundHillinzone5B;andatCopperMountain,eastofMayerinzone5B.Hydrothermallyalteredequivalentofsimilar


brecciaisextensivelyexposedsouthofUnitedVerdemineatJerome,whereitispartofDeceptionRhyoliteandCleopatraFormation

Xr2 Rhyolitic tuff—Fine-grained,porphyriticrhyolitecontainingabundantphenocrystsofpar-tiallyembayedquartz.Particularlyabundantinzones5and6.Silicifiedandleachedofalkalimetalsinmanyoutcrops.Describedasquartzporphyryinplaces(AndersonandBlacet,1972c).

AtHackberrymine,southofPolandJunctioninzone4B,andextendingtothenorth,crystal-poortuffcontainsfragmentsoffelsicvolcanicrocksandminorandesite.

AlongBlackCanyon,fromTownsendButteonthenorthtopastsouthernbound-aryofmaparea,thicksequencesofcrystal-richtuffareinterbeddedwithrhyoliteflowsandflowsoffelsiccomposition.Somebodiesoftuffcouldbehypabyssalintrusiverocks.Silicifiedandleachedofalkalimetalsinmanyoutcrops,asaresimilarrocksnorthofTownsendButte(O’Hara,1987b).Alterationtoclay-richprotolithinEarlyProterozoicfacilitateddevelopmentofhigh-strainzonealongthicksequenceoftuffdur-ingregionalmetamorphismanddeformation.Leastalteredtuffiscalc-alkalicrhyolitethatisstronglyperaluminous,verysodic,andveryFerich.

LargestbodyoftuffisexposednortheastofMayer,fromnearRoundHilltowestofCopperMountain.ThistuffislessalteredthanthosealongBlackCanyon;therefore,high-strainzonesnotdevelopedhereasopposedtozonesalongBlackCan-yon.LeastalteredtuffnorthwestofCopperMountainisstronglyperaluminous,calc-alkalictocalcic,averagetopotassic,andaverageinFe/Mgratio.

BodiesoftuffinterbeddedwithSheaBasaltsouthofJerome,nearCopperChiefmine,werereferredtoasquartzporphyry(AndersonandCreasey,1958).Leastalteredrocksarealkali-calcictocalc-alkalicrhyolitethatisslightlyperaluminous,verysodic,andaveragetoFerich.

SouthofUnitedVerdemine,alongHullCanyon,relativelyunalteredtuffisinterbeddedwithbrecciabeds.SomeofthistuffispartofCleopatraQuartzPorphyryorCleopatraFormation(AndersonandCreasey,1958;AndersonandNash,1972)thathoststhemassivesulfideoreatthemine.Othertuffisstratigraphicallyabovebedsthathostmassivesulfideore(Gustin,1990).LeastalteredtuffintheCleopatrathathostsoreiscalc-alkalicrhyolitethatismildlytostronglyperaluminous,verysodic,andaveragetoveryFerich(VanceandCondie,1987).DeceptionRhyolitehasmoderatenegativeEuanomaly,similartothatinBuzzardRhyolite(Vance,1989).LeastalteredtuffinbedsabovetheCleopatraissilicifiedandstronglyperaluminous,verysodic,andveryMgrich(Gustin,1990).

AgeofrhyolitetuffalongBigBugCreeknorthofBigBugMesainzone3Babout1,750Ma(Andersonandothers,1971)

Xr3 Rhyolitic intrusive rocks—Fine-grained,equigranulartoslightlyporphyritic,irregularlyshapedmassescontainingquartzphenocrysts.IncludeslargediscordantmasswestofYarberWashinzone5BandsmallerdiscordantbodiesinGrapevineGulchForma-tioninsouthernBlackHillsofzone6A.IntrusiverhyoliticrockshavelargenegativeEuanomalies,whichdistinguishthemfromotherrhyoliticrocks,suchasBuzzardandDeceptionRhyolites(Vance,1989)

EARLY PROTEROZOIC HYDROTHERMALLY ALTERED METAVOLCANIC ROCKS RELATED TO VOLCANOGENIC MASSIVE SULFIDE DEPOSITS

Xbh Altered basaltic rocks—Silicified,epidotized,andslightlychloritizedrockexposedinirregularlyshapedzones.AlkalimetalsstronglyleachedtoproduceAl-richrockcontainingandalusiteandsillimaniteatHuronmine,southofHumboldt,inzone4C(O’Hara,1987a)

Xah Altered andesitic rocks—Chloritizedrockexposedinlenticulartoirregularlyshapedareas.ExposedwestofMayerinzone4C,southwestofCordesJunctioninzone5A,andnearCopperMountaininzone5B.AlteredrockswestofMayergradeupwardintosilicifiedandesiteandrhyolite.SouthofJerome,inzone6B,chloritizedrocksareeitheralteredandesiteoralteredrhyolite(LindbergandJacobson,1974;Lindberg,1989;Anderson,1989b)


Xdh Altered dacitic rocks—Chlorite-richrockshavingextensiveironstaincausedbyoxidationofsulfideminerals.ExposedinlargeareafromCopperMountaintoStoddardSpringinzone5B.SmallerareaexposedalongBigBugCreek,southeastofMayer

Xd1h Altered dacitic breccia—Chlorite-richbrecciabedsinDeceptionRhyolitesouthofJeromeinzone6B

Xrh Altered rhyolitic and pyroclastic rocks—Chlorite-richrockshavingextensiveironstaincausedbyoxidationofsulfideminerals.IncludeschloritizedrhyoliteatDeSotoandBlueBellminesinzone4CandchloritizedrhyoliteatBinghamptonminesouthofRoundHillinzone5B(fig.49).

SouthofJerome,inzone6B,includeschloritizedDeceptionRhyolitebeneathUnitedVerdemassivesulfidedeposit(AndersonandNash,1972;DeWitt,1989;Lindberg,1989).LeastalteredDeceptionRhyolite(A/CNKratioof1.1;fig.49B)isprogressivelyconvertedintostronglyperaluminous(A/CNKratioof2–4)indistalzone;intoMg-richrock(A/CNKratioof4–20)inproximalzone;andintochloriteschist(A/CNKratioof45–300)beneathmassivesulfideorebody(VanceandCondie,1987;Gustin,1990).DeceptionRhyolitethatoriginallywascalc-alkalic(fig.49A)becomesstronglycalcicindistalzone;plotstorightoftheclassificationdiagraminproximalzone;andreturnstoacompositionoftrachybasalttolatiticbasaltinchloriteschist(fig.49A).DeceptionRhyolitethatwasverysodicbecomesverypotassicindistalandproximalzones;andremainsinverypotassicfieldinthechloriteschist(fig.49C).RhyolitethatwasveryFerichbecomesveryMgrichwithprogressivealteration(fig.49D).ChloriteschistshowsapparentREE,Y,andZrenrichment,whichisprobablyduetovolumereductionofDeceptionRhyoliteduringhydrothermalalteration(VanceandCondie,1987)

Xr1h Altered rhyolitic breccia—Chlorite-richbrecciabedsinDeceptionRhyolitesouthofJeromeinzone6B.Similarpatternofchemicalalterationasinalteredrhyolite

Xr2h Altered rhyolitic tuff—Chlorite-richcrystaltuffofCleopatraFormationsouthofJeromeinzone6B.Similarpatternofchemicalalterationasinalteredrhyolite.Alsoincludesmuscovite-andquartz-richrocksderivedfromtuffandcrystal-richrhyolitetuff.Cropsoutaselongatetocircularareaszonedfrommuscovite-richmarginstoquartz-richcore.ExposedeastandsoutheastofTownsendButte

Xh Altered rocks—Chlorite-richrocksderivedfromprotolithtooalteredtodeterminewithavailabledata.ExposedalongLoganWash,northwestofSkullValleyinzone2,andsouthwestofIronKingmineinzone4B.ChloriticrocksatLoganWashareamongthemostMgrichofallsamplesfromalterationzones(fig.49D)

EARLY PROTEROZOIC METAVOLCANIC ROCKS OF APPROXIMATELY KNOWN CHEMICAL COMPOSITION

[Mafictofelsicmetavolcanicflows,breccias,andtuffs.Mappedwhererocktexturesandmineralogyindicatemetavolcanicprotolith,butwherechemicalanalysesarelacking.Ageassumedsimilartothatofmetavolcanicrocksofknownchemicalcomposition]

Xmv Mafic rocks—Includesprobableandesite,basalticandesite,andbasaltflowsandminorbreccias.PrimarilybasaltflowsareexposedalongwestsideofMintWashGranodioriteinzone2.BasaltandandesiteflowsandinferredandesiticbrecciasareexposedalongwestsideoflargegabbroonSugarloafMountaininzone2.BasalttoandesiteflowsareexposedsouthofPineMountain,infarsoutheastcornerofmaparea.BasaltflowsandminordacitebodiesareexposedinalargeareanorthofSquawPeakonsouthrimofVerdeRivervalley.BasaltandandesiteexposedincanyonofAguaFriaRiver,southofRichinbarmine,nearsouthernboundaryofmaparea.Innorthernpartofthatarea,extensivemetagabbrobodiescutthebasaltandarelocallymoreabundantthanthemaficmetavolcanicrocks

Xam Amphibolite—Amphibole-plagioclaseschist.Probableprotolithofbasalt.Largestexpo-suresnorthofCottonwoodMountaininfarwesternpartofmapareaandnorthwestofPrescott,withinPrescottGranodiorite

Xiv Intermediate-composition rocks—Includesprobabledaciteandandesiteflowsandminorbreccias.DaciteabundantalongLoganWash,northwestofSkullValleyinzone1,andnorthofBoston-Arizonamineinzone2.Andesiteflowsandtuffexposedsoutheast


Figure 49. Major-element classification diagrams for hydrothermally altered Early Proterozoic felsic metavolcanic rocks (units Xrh and Xr2h) south of Jerome, stratigraphically beneath United Verde massive sulfide deposit. Data from Vance and Condie (1987), Vance (1989), Gustin (1990), and this study. Rock abbreviations defined in figure 46; field boundaries defined in figure 18. Alteration zones from Vance (1989). Note change in scale of X and Y axes in B, C, and D. Dotted blue line with arrow shows overall trend of chemical change during progressive alteration of rhyolite to chlorite schist. Two-letter abbreviations are altered rhyolite from massive sulfide deposits or prospects in Bradshaw Mountains: BH, Binghampton mine; ST, Stoddard mine; LW, Logan Wash prospect; BB, Blue Bell mine. Red arrow indicates point lies outside of plot, in direction indicated.

A/C

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30002500200015001000

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R1 = 4000Si - 11,000(Na + K) - 2000(Fe + Ti)

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Alteration of theDeception Rhyolite

Least alteredDistalProximalChlorite schist

EXPLANATION

BHST

LW

BB

BHST

LWBB

BHSTLW

BB

LW

BBSTBH


ofSlateCreekinzone3B.DacitetuffandandesitebrecciaexposedalongandsouthofCrooksCanyoninzone3B.Alargearea,mappedonlyinreconnaissance,northofHorseMountainandalongBlindIndianCreek,inzone4A,containstuffandminordaciteflows.AndesiteanddaciteflowsandinterbeddedtuffareexposedonsoutheastshoulderofSilverMountaininzone4C.SmallbodiesofandesiteareexposedalongBlackCanyoninzone5A

Xfv Felsic rocks—Includesprobablerhyodaciteandrhyolite,aswellasthinbedsofchemi-callyprecipitatedsedimentaryrockssuchasiron-formationandchert.Largestexpo-surealongBlackCanyoninzone5A,whererhyoliteandminorsedimentaryrocksaremapped(Jerome,1956).Highlystrained,peraluminousmetavolcanicrocksareprob-ablycrystaltuffandminorhypabyssalsills.RhyodaciteislocallyabundantalongGapCreekinzone6,butoutcropsalsoincludemaficmetavolcanicrocksandiron-formation(Wolfe,1983).Rhyodaciteiscalc-alkalic(fig.45A),verysodic(fig.45C),andaverageinFe/Mgratio(fig.45D)

EARLY PROTEROZOIC METATUFFACEOUS, CHEMICALLY PRECIPITATED, AND GNEISSIC ROCKS

[Metavolcanic,metasedimentary,tuffaceous,andchemicallyprecipitatedrocks.Alsoincludesmixturesoftheserocksandplutonicrocks.Ageofmetavolcanic,tuffaceous,andchemicallyprecipitatedrockspre-sumedtobesimilartothatofmetavolcanicrocksofknownchemicalcomposition]

Xt Tuffaceous metasedimentary rocks—Fine-grainedfelsictointermediate-compositiontuffandinterbeddedmetasedimentaryrocks.Numerousexposuresinzones2–6;particu-larlyabundantinzone4wherereferredtoaspartofSpudMountainFormation(Ander-sonandBlacet,1972a)andinzone6aspartofGrapevineGulchFormation(AndersonandCreasey,1967).Thicknessdifficulttoestimatebecauseofvariableintensityoffolding.

SouthofSlateCreekinzone2,unitcontainsmuchtuffofdaciticcompositionanddiscontinuousbedsofiron-formation.TuffextendspastwestedgeofmapintoZoniaminearea,whereitisinterbeddedwithfelsictointermediate-compositionflows.

WestofLynxCreekinzone3A,unitisamixtureofandesitictorhyolitictuffandminorchemicallyprecipitatedmetasedimentaryrocks.

AlongandsouthofChaparralhigh-strainzone,fromSpudMountainonthenorthtopastBigBugMesaonthesouth,inzone4A,dacitictuffisinterbeddedwithminorandesitictuff.Farthersouth,westofBattleFlat,thistuffispresentonthesideofdacitecrystaltuff(unitXd2).SoutheastofIronKingmine,andextendingbetweenBigBugMesaandLittleMesa,inzone4A,dacitictorhyodacitictuffcontainsminorandes-iticmaterial.OnwestsideofsouthernpartofBradyButteGranodioriteinzone4A,dacitictorhyodacitictuffisinterbeddedwithminorsedimentaryrocks.SouthofCrownKingtoSilverMountaininzone4C,tuffcontainsmuchsedimentarymaterialandthinbedsofiron-formationandchert.

AlargeexposureoftuffextendsfromeastofHumboldtonthenorthtoeastofMayeronthesouth(zones4Cand5B).Predominantlyvolcanicinthenorth,thetuffcontainsanincreasingpercentageofwackematerialtothesouth.Apparently,tuffgradesintowacke(unitXw)southeastofBlueBellmine.

MuchofGrapevineGulchFormationinsouthwesternBlackHills(zone6A)isfine-grainedsiliceoussedimentaryrocksandtuff.Fine-grainedsiliceoustuffisexposedalongeastsideofLonesomeValley

Xi Iron-formation, metachert, and siliceous metavolcanic rocks—Thinandlaterallydiscon-tinuousbedsofoxide-faciesiron-formation,impuremarble,metachert,andsilicifiedfelsicmetavolcanicrocks.Abundantinzone4C,betweenHumboldtonthenorthandCrownKingonthesouth,whereinterbeddedwithmafictofelsicmetavolcanicrocks.Thicknessdoesnotexceedtensofmeters.Thickandlaterallymorecontinuoussulfide-faciesiron-formationinisoclinallyfolded,thinlybeddedunitssouthofMayerinzone4C.Thicknessprobablyoriginally50–100m

Xgn Gneiss—Compositionallylayered,stronglymetamorphosedanddeformedmetavolcanictometasedimentaryrocksandminorplutonicmaterial.Mostlyquartz-feldspar-biotite-epidote-amphibolegneissandfeldspar-biotite-quartzgneiss.Exposedonlyalong


References Cited �1

Acknowledgments

BruceBryantandSteveReynoldsreviewedanearlyversionofthegeologicmap.Theirconstructivecommentsgreatlyimprovedthequalityofthemap.DiscussionswithP.F.O’HaraandPhillipAndersonabouttheProterozoicevolu-tionofArizonagreatlyaidedtheseniorauthor.P.M.BlacetisthankedforhisinputonthegeologynearMartinMountainandthesouthernBradshawMountains.D.M.Hirschberg(USGS),NancyShock(NationalParkService),andGuyPinhassiandStephenPitts(UniversityofArizona)preparedtheinitialdigitalgeologicdatabase.TammyFancherandLaurieMorath(USGS)digitizedthepointdata.

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SycamoreCreekinwesternpartofmaparea.MaybepartlycrustofMojaveprovincethatisolderthan1,760MaandyoungervolcanicrocksofCentralArizonaprovince(WoodenandDeWitt,1991)

Xm Migmatite—Mixtureofleucogranite(unitXlg),gneissicgranite(unitXgg),peliticmetasedimentaryrocks(unitXp),andminorgabbro(unitXgb)exposedinlargeareainSantaMariaMountains,centeredonBrushyMountain.MixtureofCrooksCanyonGranite(unitXcc),metasedimentaryrocks(unitXs),tuff(unitXt),andminorGovern-mentCanyonTonalite(unitXgc)exposednearQuartzMountain,eastofWilhoit

Anderson,C.A.,Blacet,P.M.,Silver,L.T.,andStern,T.W.,1971,RevisionofPrecambrianstratigraphyinthePrescott-Jeromearea,YavapaiCounty,Arizona:U.S.GeologicalSurveyBulletin1324–C,p.C1–C16.

Anderson,C.A.,andCreasey,S.C.,1958,GeologyandoredepositsoftheJeromearea,YavapaiCounty,Arizona,with sections ontheUnitedVerdeExtensionminebyG.W.H.Normanand ontheCherryCreekminingdistrictbyR.E.Lehner:U.S.GeologicalSurveyProfessionalPaper308,185p.,13plates.

Anderson,C.A.,andCreasey,S.C.,1967,GeologicmapoftheMingusMountainquadrangle,YavapaiCounty,Ari-zona:U.S.GeologicalSurveyGeologicQuadrangleMapGQ–715,scale1:62,500.

Anderson,C.A.,andNash,J.T.,1972,GeologyofthemassivesulfidedepositsatJerome,Arizona—Areinterpretation:EconomicGeology,v.67,p.845–863.

Anderson,Phillip,1989a,Proterozoicplatetectonicevolu-tionofArizona,inJenney,J.P.,andReynolds,S.J.,eds.,GeologicevolutionofArizona:ArizonaGeologicalSocietyDigest17,p.17–55.

Anderson,Phillip,1989b,Stratigraphicframework,volcanic-plutonicevolution,andverticaldeformationofthePro-terozoicvolcanicbeltsofcentralArizona,inJenney,J.P.,andReynolds,S.J.,eds.,GeologicevolutionofArizona:ArizonaGeologicalSocietyDigest17,p.57–148.

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Table 1. Geochronologic data, in order of increasing age, for the map area

�0’ x �0’ Sample Type of Mineral or Age Uncertainty Rock name Map unit� Primary reference� Notes quadrangle1 number analysis� material (Ma) (Ma) or location� analyzed�

Prescott CD2 K-Ar WR 4.6 0.2 Perkinsville Tby McKeeandAnderson(1971)Prescott PA3 K-Ar WR 4.6 0.2 Perkinsville Tby McKeeandAnderson(1971)Prescott CD4 K-Ar WR 4.8 0.2 Perkinsville Taby McKeeandAnderson(1971)Prescott CD7 K-Ar WR 4.96 0.2 Perkinsville Taby McKeeandAnderson(1971)Sedona UAKA-unknown K-Ar WR 5.45 0.18 Verde Taby Donchin(1983)Williams BA-78-82 K-Ar WR 5.5 0.2 InEastJuniperMts Tby Goffandothers(1983)Sedona UAKA-unknown K-Ar WR 5.66 0.17 Verde Taby Donchin(1983)Sedona VV1 K-Ar WR 5.68 0.2 Verde Taby McKeeandAnderson(1971)Sedona UAKA-71-39 K-Ar glass 5.69 0.22 Verde Tvg Scarborough(1975)Williams BA-78-90 K-Ar WR 6.2 0.3 InEastJuniperMts Tby Goffandothers(1983)Sedona UAKA-71-22 K-Ar glass 6.24 1.0 Verde Tve Scarborough(1975)Prescott PA2 K-Ar WR 6.26 0.3 Perkinsville Tby McKeeandAnderson(1971)Sedona UAKA-77-72 K-Ar WR 6.4 0.25 AtHorseMesa Taby Pierceandothers(1979)Sedona UAKA-77-75 K-Ar WR 6.55 0.23 AtSlideRock Taby Pierceandothers(1979)Payson B2 K-Ar WR 7.4 1.9 Thirteenmile Tbo McKeeandElston(1980)Payson A4a K-Ar WR 7.7 0.8 Thirteenmile Thb McKeeandElston(1980) Locationinaccurate; plotsinHickeyFm.Payson UKA-71-19 K-Ar glass 7.8 0.23 Verde Tvg Scarborough(1975)Payson T-1 K-Ar bt 7.9 0.5 Thirteenmile Tdo McKeeandElston(1980)Prescott CD6 K-Ar WR 8.0 0.3 Perkinsville Taby McKeeandAnderson(1971)Sedona MM-2A K-Ar WR 8.15 0.3 AtOakCreek Tbo McKeeandMcKee(1972)Payson B1 K-Ar WR 8.3 2.2 Thirteenmile Tbo McKeeandElston(1980)Payson B3 K-Ar WR 8.3 0.8 Thirteenmile Tbo McKeeandElston(1980)Payson B5 K-Ar WR 8.3 0.5 Thirteenmile Tbo McKeeandElston(1980)Payson B-1 K-Ar WR 8.5 1.3 Thirteenmile Tdo McKeeandElston(1980)Payson UAKA-73-162 K-Ar WR 9.18 0.28 Thirteenmile Tbo Pierceandothers(1979) Location approximate.Payson B7 K-Ar WR 9.2 0.4 Thirteenmile Tbo McKeeandElston(1980)Payson T6 K-Ar WR 9.3 0.4 Thirteenmile Tbo McKeeandElston(1980) Nolocation.Sedona UAKA-77-162 K-Ar WR 9.66 0.35 Thirteenmile DikeinTbo Pierceandothers(1979) Eastofmap.Williams NPB-1 K-Ar hb 9.8 0.7 AtPicachoButte Trdo Goffandothers(1983) Northofmap.Payson B8 K-Ar WR 10.0 0.7 Hickey Thb McKeeandElston(1980) .Payson B9 K-Ar WR 10.0 0.7 Hickey Thb McKeeandElston(1980)Payson B11 K-Ar WR 10.2 0.4 Hickey Thb McKeeandElston(1980)Bradshaw MY8 K-Ar WR 10.4 0.4 Hickey Thb McKeeandAnderson(1971)Payson B10 K-Ar WR 10.4 0.8 Hickey Thb McKeeandElston(1980)Sedona UAKA-77-164 K-Ar WR 10.57 0.31 Thirteenmile Tbo Pierceandothers(1979)Bradshaw unknown K-Ar WR 10.6 Hickey Thb Leighty(1997)Bradshaw MY6 K-Ar WR 10.7 0.4 Hickey Thb McKeeandAnderson(1971)Payson T13 K-Ar bt 10.7 0.6 Hickey Thb McKeeandElston(1980)Payson B12 K-Ar WR 11.3 2.6 Hickey Thb McKeeandElston(1980)Payson T14 K-Ar bt 11.3 0.7 Hickey Thb McKeeandElston(1980)

References Cited

��

Table 1. Geochronologic data, in order of increasing age, for the map area.—Continued


Payson B23 K-Ar WR 11.3 1.8 Hickey Thb McKeeandElston(1980)Bradshaw MY7 K-Ar WR 11.35 1.8 Hickey Thb McKeeandAnderson(1971)Sedona MM3A K-Ar WR 11.4 0.5 Hickey Thb McKeeandMcKee(1972) Northeast(?)of CasnerButte.Payson B22 K-Ar WR 11.5 0.8 Hickey Thb McKeeandElston(1980)Payson B24 K-Ar WR 11.5 0.4 Hickey Thb McKeeandElston(1980)Payson B17b K-Ar WR 11.6 0.3 Hickey Thb McKeeandElston(1980)Payson B18 K-Ar WR 11.6 0.6 Hickey Thb McKeeandElston(1980)Payson B19 K-Ar WR 11.6 0.2 Hickey Thb McKeeandElston(1980)Prescott MM2 K-Ar WR 11.9 0.5 Hickey Thb McKeeandAnderson(1971)Payson B15 K-Ar WR 12.0 1.3 Hickey Thb McKeeandElston(1980)Payson B16 K-Ar WR 12.0 1.2 Hickey Thb McKeeandElston(1980)Sedona PED-29-66 K-Ar WR 12.1 1.3 Hickey Thb Pierceandothers(1979) Location approximate.Sedona K-Ar WR 12.2 Hickey Thb Damon(1968) Eastofmap.Bradshaw MM3 K-Ar WR 12.9 2.2 Hickey Thb Damon(1968) Unknownlocation.Payson B21 K-Ar WR 13.1 2.2 Hickey Thb McKeeandElston(1980)Prescott UAKA-67-09 K-Ar WR 13.2 0.8 Hickey Thb Shafiqullahandothers(1980)Prescott PR3 K-Ar WR 13.4 0.5 Hickey Thb McKeeandAnderson(1971)Bradshaw MY5 K-Ar WR 13.47 0.5 Hickey Thb McKeeandAnderson(1971)Prescott MM1 K-Ar WR 13.7 0.5 Hickey Thb McKeeandAnderson(1971)Sedona K-Ar WR 13.75 Hickey Thb Damon(1968) Location approximate.Prescott PR2 K-Ar WR 13.8 0.5 Hickey Thb McKeeandAnderson(1971)Sedona UAKA-66-55 K-Ar WR 13.9 0.3 Hickey Thb Shafiqullahandothers(1980)Bradshaw MU2 K-Ar WR 13.9 0.5 Hickey Thb McKeeandAnderson(1971)Prescott CD1 K-Ar WR 14.32 0.6 Hickey Thb McKeeandAnderson(1971)Sedona K-Ar WR 14.6 Hickey Thb Ranney(1988)Sedona UAKA-77-168 K-Ar WR 14.6 0.4 Hickey Thb Pierceandothers(1979)Sedona MM3B K-Ar WR 14.7 0.6 Hickey Thb McKeeandMcKee(1972) Northeast(?)of CasnerButte.Bradshaw UAKA-76-26 K-Ar bt 14.9 0.33 AtGabarinaHill Tr Christman(1978)Prescott A-43orMM4 K-Ar bt 15.0 1.1 Hickey Tht Kriegerandothers(1971)Bradshaw K3 K-Ar bt 15.0 0.5 MilkCreek Tmcd McKeeandAnderson(1971)Bradshaw K2 K-Ar bt 15.2 0.5 MilkCreek Tmcd McKeeandAnderson(1971)Sedona ES-64 K-Ar WR 15.4 2.1 Hickey Thb EberlyandStanley(1978)Bradshaw MY1 K-Ar hb 18.9 0.5 Hickey Tht McKeeandAnderson(1971) MaybeinunitTla.Prescott UAKA-76-90 K-Ar WR 21–28 0.51 SullivanButtes Tla Shafiqullahandothers(1980)Prescott A-43orPA5 K-Ar bt 24.0 1.0 SullivanButtes Tlal Kriegerandothers(1971)Williams K-Ar WR 24.4 1.2 InEastJuniperMts Tla Goffandothers(1983)Bradshaw 89-23 FT ap 25 2 GovernmentCanyon Xgc Fosterandothers(1993) Reheatingoruplift age.

�0

Geologic Map of the Prescott N

ational Forest and the Headwaters of the Verde River, Arizona

Prescott A-44orPA4 K-Ar hb 27.3 1.1 SullivanButtes Tlal Kriegerandothers(1971)Bradshaw 89-25 FT ap 30 3 GovernmentCanyon Xgc Fosterandothers(1993) Reheatingoruplift age.Williams K-Ar bt 32.0 2 InEastJuniperMts Tla Goffandothers(1983)Bradshaw 89-24 FT ap 33 2 GovernmentCanyon Xgc Fosterandothers(1993) Reheatingoruplift age.Williams K-Ar bt 36.1 1.2 InEastJuniperMts Tla Goffandothers(1983)Prescott 89-27 FT ap 42 4 Prescott Xpr Fosterandothers(1993) Upliftorcoolingage.Prescott 89-26 FT ap 48 3 Prescott Xpr Fosterandothers(1993) Upliftorcoolingage.Bradshaw K-Ar bt 64 Walker Kt Anderson(1968)Bradshaw K-Ar bt 64.7 2.3 CrownKing Kt Armstrong,R.L.,unpub.data, citedinReynoldsandothers(1986).Prescott PK4 FT ap 67 6 Yava Yy Fosterandothers(1993) 1047-mdepthin PK-StateA-1well 55-614743.Bradshaw K-Ar bt 70 BigBug Kt Anderson(1968)Bradshaw UAKA-76-25 K-Ar hb 72.6 1.5 CopperBasin Kt Christman(1978)Bradshaw UAKA-76-01 K-Ar bt 72.8 1.5 CopperBasin Kt Christman(1978)Bradshaw UAKA-76-01 K-Ar hb 72.9 1.5 CopperBasin Kt Christman(1978)Prescott PK6 FT ap 73 5 Yava Yy Fosterandothers(1993) 1672-mdepthin PK-StateA-1well 55-614743.Prescott PK7 FT ap 75 9 Yava Yy Fosterandothers(1993) 1984-mdepthin PK-StateA-1well 55-614743.Bradshaw UAKA-75-117 K-Ar bt 75.5 1.6 CopperBasin Kt Christman(1978)Prescott 89-28 FT ap 80 5 Cherry Xch Fosterandothers(1993) Upliftage.Prescott 89-29 FT ap 91 8 Cherry Xch Fosterandothers(1993) Upliftage.Prescott 89-30 FT ap 91 9 Cherry Xch Fosterandothers(1993) Upliftage.Prescott 90-204 FT ap 94 9 Cherry Xch Fosterandothers(1993) Upliftage.Prescott PK1 FT ap 104 12 Yava Yy Fosterandothers(1993) 100-mdepthin PK-StateA-1well 55-614743.Prescott 89-31 FT ap 107 11 Cherry Xch Fosterandothers(1993) Upliftage.Prescott PK5 FT ap 113 10 Yava Yy Fosterandothers(1993) 13,559-mdepthin PK-StateA-1well 55-614743.Prescott PK2 FT ap 133 20 Yava Yy Fosterandothers(1993) 422-mdepthin PK-StateA-1well 55-614743.Bradshaw UAKA-57-4 K-Ar bt 766 25 Prescott? Xpr? Shafiqullahandothers(1980)Prescott K-Ar bt 1110 40 Dells Yd Shafiqullahandothers(1980) Coolingage.Bradshaw Ar-Ar bt 1188– 4 HorseMountain Xhm HodgesandBowring(1995) Reheatingage. 1195. Bradshaw USGS(W)-123 K-Ar bt 1235 60 BradyButte Xbb MarvinandCole(1978) Coolingage.Bradshaw USGS(W)-123 Rb-Sr bt 1240 60 BradyButte Xbb MarvinandCole(1978) Coolingage.Bradshaw K-Ar bt 1250 KirklandPeak Ykp Shafiqullahandothers(1980)

References Cited

�1

Table 1. Geochronologic data, in order of increasing age, for the map area.—Continued


Bradshaw USGS(W)-550 K-Ar bt 1270 60 BradyButte Xbb MarvinandCole(1978) Coolingage.Prescott Rb-Sr WR 1282 100 NorthofMayer Xb Lanphere(1968) 3-pointisochron;Sri =0.714;tooyoung.Prescott USGS(W)-CAA-8 Rb-Sr WR 1310 50 Dells Yd MarvinandCole(1978)Williams K-Ar bt 1340 50 SouthButte Xsb Shafiqullahandothers(1980) Coolingdate.Prescott USGS(W)-CAA-6 K-Ar bt 1360 40 Prescott Xpr MarvinandCole(1978) Coolingage.Prescott U-Pb zr 1395 8 Dells Yd Silverandothers(1984)Bradshaw Ar-Ar ms 1410 10 CrazyBasin Xcb Hodges,Bowring,andHames(1994) Coolingage. plateau.Bradshaw Ar-Ar bt 1412 5 CrazyBasin Xcb Hodges,Bowring,andHames(1994) Coolingage. plateau.Williams K-Ar ms 1460 50 SouthButte Xsb Shafiqullahandothers(1980) Coolingdate.Prescott Rb-Sr WR 1493 80 WestofYaegerCanyon Xr Lanphere(1968) 3-pointisochron;Sri =0.706;tooyoung.Bradshaw PED-4-60 K-Ar ms 1500 50 CrazyBasin Xcb Shafiqullahandothers(1980)Prescott Rb-Sr WR 1547 50 WestofMayer Xb Lanphere(1968) 3-pointisochron;Sri =0.7045;tooyoung.Prescott Rb-Sr WR 1576 85 Deception Xrd Lanphere(1968) 4-pointisochron;Sri =0.705;tooyoung.Bradshaw USGS(W)-CAA-5 Rb-Sr WR 1610 90 CrazyBasin Xcb MarvinandCole(1978) Minimumage;Sri assumedat0.704.Prescott CAA-12,localityG K-Ar hb 1625 Cherry Xch Lanphere(1968)Payson SP-1 K-Ar bt 1643 Cherry Xch Roe(1976) Coolingage.Prescott USGS(W)-CAA-2 K-Ar bt 1670 80 Cherry Xch MarvinandCole(1978)Prescott U-Pb zr 1680 Prescott Xpr WoodenandDeWitt(unpub.data,2004)Bradshaw U-Pb zr 1680 5 HorseMountain Xhm HodgesandBowring(1995)Prescott CAA-12,localityF Ar-Ar hb 1682 24 Cherry Xch DalrympleandLanphere(1971,1974) Plateauage plateau. supercededby newerdata.Prescott CAA-12,localityF K-Ar bt 1689 Cherry Xch Lanphere(1968)Prescott CAA-12,localityG K-Ar bt 1693 Cherry Xch Lanphere(1968)Prescott CAA-12,localityF K-Ar hb 1694 Cherry Xch Lanphere(1968)Bradshaw U-Pb zr 1700 10 CrazyBasin Xcb Bowring,unpub.data,citedin HodgesandBowring(1995).Prescott CAA-12,localityF Ar-Ar hb 1707 15 Cherry Xch DalrympleandLanphere(1971,1974) totalgas.Prescott U-Pb zr 1717 VerdeRiver Xvr Chamberlainandothers(1991)Bradshaw U-Pb zr <1720 TexasGulch Xtgr Bowring,unpub.data,citedin Locationunknown. KarlstromandBowring(1991).Prescott U-Pb zr 1720 MintWash Xmw WoodenandDeWitt(unpub.data,2004)Bradshaw U-Pb zr 1720 HumbugCreek Xhc WoodenandDeWitt(unpub.data,2004)Bradshaw U-Pb zr 1720 Hassayampa Xh WoodenandDeWitt(unpub.data,2004)

��



Bradshaw U-Pb zr 1720 Bland Xbl Bowringandothers(1986) Southofmap.Bradshaw U-Pb zr 1720– Bland-Bumblebee Xbl Bowringandothers(1986) 1740.Bradshaw U-Pb zr 1730 CrooksCanyon Xcc Bowring,unpub.data,citedin Locationunknown; KarlstromandBowring(1991). 3samplelocalities.Prescott JS-05-51 U-Pb zr 1738.5 2.8 Deception Xr

2h Slackandothers(2007) 4-pointdiscordia.

Prescott U-Pb zr 1740 15 Cherry Xch Andersonandothers(1971) 2-pointdiscordia.Prescott U-Pb zr 1740 Cherry Xch Bowring,unpub.data,citedin Locationprobably Karlstromandothers(1987). inaccurate.Prescott U-Pb zr 1740 GovernmentCanyon Xgc Bowring,unpub.data,citedin Locationunknown. Karlstromandothers(1987).Prescott U-Pb zr 1740 Deception Xr

2h? Bowring,unpub.data,citedin Locationunknown.

KarlstromandBowring(1991).Bradshaw U-Pb zr 1743 BadgerSpring Xbs Bowring,unpub.data,citedin Locationunknown. Karlstromandothers(1987).Prescott U-Pb zr 1750 15 GovernmentCanyon Xgc Andersonandothers(1971) 2-pointdiscordia.Bradshaw U-Pb zr 1750 BradyButte Xbb Bowring,unpub.data,citedin Locationunknown. KarlstromandBowring(1991).Bradshaw U-Pb zr 1750 10 BradyButte Xbb Andersonandothers(1971) 6-pointdiscordia;3 pointsatlocation4.Bradshaw U-Pb zr 1755 10 BradyButte Xbb Andersonandothers(1971) 6-pointdiscordia;3 pointsatlocation3; locationunknown.Bradshaw U-Pb zr 1755 10 AlongBigBugCreek Xr Andersonandothers(1971) 3-pointdiscordia; location2.Bradshaw U-Pb zr 1755 AlongBigBugCreek Xr Bowring,unpub.data,citedin Locationunknown. KarlstromandBowring(1991).Prescott U-Pb zr 1800 10 Deception Xr

2h Andersonandothers(1971) 2-pointdiscordia;

datesupercededby newdata.

1Bradshaw=BradshawMountains.2K-Ar,potassium-argon;FT,fissiontrack;Rb-Sr,rubidium-strontium;U-Pb,uranium-lead;Ar-Ar,40argon-39argon.3wr,wholerock;bt,biotite;ms,muscovite;hb,hornblende;zr,zircon;ap,apatite.4Rocknamedoesnotcontaindescriptivelocationinformation(At,Along).Locationinformation,especiallyformanysamplesofProterozoicrocks,isupdatedfromthatinReynolds

andothers(1986).5Mapunitsymbolsongeologicmap.6Allagesreportedbefore1986aresummarizedinReynoldsandothers(1986). References Cited

��

Table 2. Deep water wells for which interpreted logs were provided by this study

[Ifmorethanoneunitsymbolisshownforadepthinterval,theonelistedfirstisthepreferredinterpretation.ADWRNo.,ArizonaDepartmentofWaterResourcesidentificationnumber(55-xxxxxx)—lastsixdigitslisted.Xu,EarlyProterozoicrocks,undivided]

Name or �0’ x �0’ Unit1 Depth1 Unit� Depth� Unit� Depth� Unit� Depth� Unit� Depth� Unit� Depth� Unit� Depth� Unit� Depth� Unit� Depth�ADWR No. quadrangle

502596 Bradshaw Tso 535 Xgc 760

503114 Bradshaw Tso 700

503135 Bradshaw Tso 185 Tso? 550 Xgc 865

506091 Bradshaw Ths 78 Thb 320 Thc 385 Ths 500

506299 Bradshaw Tm 135 Tmd 300

510079 Bradshaw TfyorTso 640

512478 Bradshaw Thb 340

514426 Bradshaw QTs 185 Tto 205 Tbo 220 Tto 420 Tbo 510 Tto 820 Tmo 845 Tto 920 Tbo 1010


521052 Bradshaw Tm 340

521766 Bradshaw Tso 280 XgcotTso? 540 Xgc 620

521786 Bradshaw QTs 240









530529 Bradshaw Tso 219 Tbo 285

530653 Bradshaw Tso 40 Tbo 220

532350 Bradshaw Tso 430 Tmo 507

533225 Bradshaw Thsb 61 Xmv 500

533791 Bradshaw Tm 250 Tmd 333



565855 Bradshaw Ths 408 Xmv 455 Xbs 550



592720 Bradshaw Xmv 1000

516725 Payson Qs 93 Tve 400 Tv 510

529824 Payson Thb 540

#1Walton- Prescott QTs 550? MrorDm 1350 Xu 2060

State oret

085708 Prescott Thc 290 Tht? 340 Ths 435

085961 Prescott QTs 170 Thb 435

086001 Prescott QTs 450 Yd 460

200027 Prescott QTs 490 Dm 507

200028 Prescott QTs 850 Tby 880 Tsy 1620 Dm 1900

��





500772 Prescott Ths 260 Xmv 467

501069 Prescott QTs 672

501405 Prescott QTs 109 ThborThc 618

501889 Prescott Tvl 649 Tvls 724



504646 Prescott Qal 75 Thb 275 Tv 480


505300 Prescott Tv 935

505305 Prescott QTs 220 Tsv 300 Tla? 370 Tsv? 464

505514 Prescott QTs 196 MrorDm 315

505516 Prescott QTs 490 ThborThc 610 Xmw 628

505772 Prescott QTs 267 Tmu 370

506636 Prescott ThborThc 215 Ths 530

507354 Prescott ThborThc 90 Ths 610 Xpr 703

507484 Prescott QTs 140 Tby 240

507612 Prescott Ths 170 YXgr 460


508594 Prescott Thb 480 YXgr 505

509151 Prescott QTs 100 Tht 180 Tmu? 570 YXgr 608

509536 Prescott QTs 250 Tht? 270 Tmu 440

510778 Prescott QTs 250 Ths 300 Thb 435 Ths 540


511566 Prescott QTs 460 Xmv 505

511817 Prescott QTs 190 Tht 270 Tsu?or 445

Tsv?

512326 Prescott QTs 300 Thbs 470 Xgbor 558

YXgr


512969 Prescott Thb 140 ThcorThs 360 Xmw 425


513290 Prescott Qf 30 Tvl 540 Tvls 655



518809 Prescott ThborThs 210 Ths 595

518861 Prescott Ths 415


519056 Prescott QTs 85 Thb 312 Ths 354

519687 Prescott QTs 702 Thb 740 Ths? 865 Thb? 926

521679 Prescott QTs 195 Xgr 385



524200 Prescott QTs 180 Thb 325 Ths 375 Xmvor 600

Xgb

525770 Prescott QTs 180 Tht 315 Ths 380 Tla? 490 Tos? 525

References Cited

��

��



Table 2. Deep water wells for which interpreted logs were provided by this study.—Continued


526305 Prescott QTs 435 Thb 540 Ths 560 Thb 595



526910 Prescott QTs 220 Thb 470 Thb? 508

528270 Prescott QTs 426 TlaorTby 448

528744 Prescott Qf 60 Tvl 720 Tvls 765 Tvl 1200

530375 Prescott QTs 835 YXgr 840

530642 Prescott Qal 65 Thb 490 Tmu 560

530649 Prescott QTs 110 Thb 380 Ths? 420 Tmu 520

530748 Prescott Qf 30 Tvl 315 Tvls 440 Tvl 560 Tvls 805 Tvl 905

531578 Prescott Qal 175 Tv 555 Tvg 900



533110 Prescott Qt 175 Tvls 390 Tvl 555 Tvg 920 Thb 1115 Ths 1203

533639 Prescott Ths 150 Thb 220 Ths 305

533713 Prescott QTs 187 ThtorTvu 408 Tsu 507 Xgr? 510

534727 Prescott QTs 240 XmvorXgb 705


535934 Prescott QTs 305 YXgrorXgb 618

536623 Prescott QTs 755 Thb 828 Xmv 861

536694 Prescott QTs 270 TsyorTby? 330

537399 Prescott QTs 250 Thbs 350 Thb 507


538428 Prescott Qal 20 YXgrorXcca 400

538446 Prescott Thb 295 Xmw 510



540640 Prescott Tla 716

541373 Prescott QTs 620 Thb 660 Xu 667


541942 Prescott QTs 168 Tsv 215 Tmu 280

541955 Prescott Tvg 720

543638 Prescott Ths 365 Xpr 570


545356 Prescott Qf 20 Tv 450 Tvls 480 Tv 670 Tvls 700


545527 Prescott Qs 100 Thb 320 Ths 340 Xgb 465

548845 Prescott Tby 118 Tbsy 250 YXgr 305

549009 Prescott ThborThs 275 Ths 345 Xpr 382

549501 Prescott QTs 290 Thb 590 Ths 600 Xmv 605

549559 Prescott Tv 770

552135 Prescott Tby 70 Tsy? 210 TsyorLost 533

circulation

References Cited

��556746 Prescott QTs 340 Xmw 370


557485 Prescott Tby 366 Tsy 461 Tby 516



560414 Prescott Qf 72 Tvl 340 Tvls 485 Tvl 1025


561786 Prescott QTs 72 TbyorTcy 204 Tsy 400

562060 Prescott Tvg 610




566349 Prescott Tvg 620 Thb 790


566785 Prescott Tby 210 Tcy 370

566799 Prescott QTs 470 Tbo 700





568232 Prescott QTf 120 TbyorTla 300 Tmu 340

568261 Prescott QTf 200 Tmu 230 MDrm 380



569301 Prescott QTs 312 Thb 375 Ths 400 YXgr 418

569724 Prescott QTs 195 Tmu 322 Tv? 500


569852 Prescott Thb 115 Ths 340 Xmw 506





572621 Prescott QTs 310 Thb 405 ThcorThb 490 Ths 510



573472 Prescott Tht 180 Xmw 305 Xmv 600




575592 Prescott QTs 780 Thb 905 Ths 1065 Xmv 1085





578237 Prescott QTs 360 Tco? 395 Tbu 500

578737 Prescott QTs 730 Thb 980 Ths 1095

��





579280 Prescott QTs 275 Mr 415

579607 Prescott QTs 290 Tbo? 390 Tla 480

580881 Prescott QTf 195 TbyorTsy 245 Tla 300


582491 Prescott QTs 25 TbyorTcy 450


583143 Prescott QTs 335 Thsb 505 Thb 956


583487 Prescott QTs 160 Tmu 200 Tos? 315

583547 Prescott QTs 605 Thb 660 Ths 750 YXgr 805

587403 Prescott Qs 55 Thb 520 Tla 600 Dmor 820 Xu 840

et

587404 Prescott Qal 112 Thb 360 Tla 430 Tos 485 Dm 500 et 620 Xmp? 640 YXgr? 645

oret

588619 Prescott QTs 704 Thb? 724 Ths 1190 YXgr 1240

591609 Prescott QTsorTsy 1500


613043 Prescott QTs 748 Thb 790 YXgr 905

614743 Prescott Yy 6500

648773 Prescott Tvg 831 Thb 834

AV72-12 Prescott Qf 50 Tv 1252

AV72-3 Prescott Qf 110 Tv 1780 Tvg 1990 Thb 2078

AV77-25 Prescott Notlogged 4175

BH-3 Prescott QTs 710 Tbo? 760 Tso 1408 Ywc 1450

Bull178502ft Prescott QTs 245 Tla 275 Tos 502

Bull178512ft Prescott QTs 512

Bull178562ft Prescott QTs 496 Tmu 502 Tos? 562

Bull178625ft Prescott QTs 256 Tmu 625

Bull178690ft Prescott QTs 255 Tsv 690

CityofPrescott Prescott QTs 63 Tby 100 Tbsy 290 Tos? 415 Xt 880

DRM-2 Prescott QTs 125 TbyorTsy 350 Tso 600

Fed#1 Prescott MrorDm 650 et 845 Xu 1205

HR-2 Prescott TbyorTcy 485 Demt 500

Krieger1013ft Prescott QTs 1003 Thb 1013

Krieger300ft Prescott QTs 300

Krieger310ft Prescott QTs 296 Tmu 310

Krieger370ft Prescott Thb 20 Ths 370



Krieger453ft Prescott QTs 236 Tsv 453


Krieger576ft Prescott Thb 75 Ths 451 Thb 576


References Cited

��Krieger644ft Prescott QTs 550 Tsv 644

Krieger667ft Prescott QTs 140 Tmu 474 Tsu? 659 Xg? 667



Krieger710ft Prescott QTs 582 Tmu 666 MDrm? 710

Krieger744ft Prescott QTs 315 TmuorTsu 744


Krieger812ft Prescott QTs 650 Thb 792 Ths 812

Krieger894ft Prescott QTs 600 Thb 640 Ths 894

KriegerBull178 Prescott QTs 150 Tmu 542

Krieger-2644ft Prescott QTs 450 Tmu 630 Tos? 644

Krieger-2700ft Prescott QTs 637 Tmu 700

MW-3 Prescott QTs 550 Tbo 570

MW-4 Prescott QTs 600 Tbo 675

Ostenaa522ft Prescott QTf 522

Ostenaa531ft Prescott QTs 455 TlaorTc 531

Ostenaa690ft Prescott QTs 690

Ostenaa822ft Prescott QTs 515 Tla 822

Ostenaa-2690ft Prescott Tsy 398 TbyorTc 480 TsyorTso 676 Xu 690

Schwalen420ft Prescott QTs 400 Tvu 420

Schwalen460ft Prescott QTs 460

SL-1 Prescott Tby 170 Tbsy 250 YXgr 285

WRA298ft Prescott QTs 50 Tby 280 Mr 298

WRA300ft Prescott QTf 140 Tla 300

WRA307ft Prescott QTf 290 Tmu 307

WRA380ft Prescott QTf 360 Tmu 380

WRA550ft Prescott QTs 348 Tla 422 Tos 550

WRA600ft Prescott QTs 469 Tla 570 Tos 600

WRA615ft Prescott QTs 570 TbuorTla 615

WRA625ft Prescott QTs 522 TlaorTbo 610 Tso 625

500663 Sedona Tv 1120

501377 Sedona Qal 43 Tvls 410

501424 Sedona Qs 79 Thbs 507 Ths 546 hs 660 Mr 827

503843 Sedona Qs 42 Tv 183 Tso 434

504695 Sedona Qs 50 Tv 140 Tvls 800

506444 Sedona Tvls 165 Tv 601

506470 Sedona Tv 440

509630 Sedona Qal 43 Tvl 91 Tve 585

511022 Sedona QTf 50 Tvl 230 Tvls 291 Tvl 475 Tvls 573

519065 Sedona Tv 148 Taby 190 Tv 500

520064 Sedona Tv 1300 TvorTso? 1405

525431 Sedona Qs 70 Tv 438 Thb 456

527207 Sedona Tv 283 TabyorTsy 388 Tso 486 Thb 600

529545 Sedona QTf 34 Tvl 635 Tvls 714

533124 Sedona Tvl 171 Tvls 519 Tvl 642 Tvls 757 Tv 821

543554 Sedona Thbs 260 Thb 500

100





550592 Sedona Tv 310 Thbs 420 hs? 435

555087 Sedona Tv 254 Taby 357 Tvls 400

556109 Sedona Tvl 604 TabyorTbu 606



577288 Sedona QTt 38 Tvl 210 Tvls 425


581586 Sedona Tv 185 TvorTsy? 280 Taby?or 405

orTso? Thb?

581616 Sedona Tv 340 TvorTsy 525 Thb 700 hs? 780

orTaby?

587408 Sedona TvorTve 833




609337 Sedona Tv 490 Tvls 1176 Tv?orhs? 1270

614259 Sedona Tv 595 Tvls 1000 Tso 1485

AZVerdeOil#1 Sedona Tvl 800 Tve? 1625?

AZVerdeOil#2 Sedona TvorTve 1225

Cottonwood#1 Sedona Tv 250 Tvls 650 Tso 1180

026612 Williams QTs 505 Tby 573 Tsy 630


074401 Williams QTs 370 Tby 534 Tsy 560 Tby 580 Tsy 600


519568 Williams Tso? 410 et? 485

520534 Williams QTs 503

525566 Williams QTs 730 Tby 744

532829 Williams QTs 2290 Tla 2445

540650 Williams Tso 335 et 440

564580 Williams QTs 650 YXgr 715 XtorYXgr 755

579656 Williams QTs 540 QTs?oret? 560



645843 Williams Tbsy 720

Ostenaa311ft Williams Qal 28 Tby 230 Tsy 311

Ostenaa500ft Williams QTs 500

Ostenaa528ft Williams QTs 398 Tby 438 Tsy 446 Tby 528

Ostenaa550ft Williams QTs 550

Ostenaa600ft Williams QTs 437 Tby 600

Ostenaa602ft Williams QTs 402 Tby 431 Tsy 448 Tby 602

Ostenaa630ft Williams QTs 418 Tby 442 Tby? 466 Tby 630

Ostenaa-2600ft Williams QTs 502 Tby 600

Geologic Map of the Prescott National Forest and the Headwaters of ...

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