Early Paleozoic. Periods of the Early Paleozoic ► Cambrian: 570-505 mya ► Ordovician: 505-438...

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Early Paleozoic Early Paleozoic
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Transcript of Early Paleozoic. Periods of the Early Paleozoic ► Cambrian: 570-505 mya ► Ordovician: 505-438...

Early PaleozoicEarly Paleozoic

Periods of the Early PaleozoicPeriods of the Early Paleozoic

► Cambrian: 570-505 myaCambrian: 570-505 mya

► Ordovician: 505-438 myaOrdovician: 505-438 mya

► Silurian: 438-408 myaSilurian: 438-408 mya

Overview of PaleozoicOverview of Paleozoic

► Broad Sequence of EventsBroad Sequence of Events Gradual Marine invasion of low continentsGradual Marine invasion of low continents

Wide epeiric (shallow) seas; moderated Wide epeiric (shallow) seas; moderated climateclimate► Wide shallow habitats for marine organismsWide shallow habitats for marine organisms

Epeiric seas retreated; instability occurredEpeiric seas retreated; instability occurred► Thick sedimentary layers and Volcanic Thick sedimentary layers and Volcanic

deposits developeddeposits developed

Collisional Mountain ranges builtCollisional Mountain ranges built

Plate Tectonic EventsPlate Tectonic Events

► Break-up of RodiniaBreak-up of Rodinia► Oceanic closing and orogeny Oceanic closing and orogeny

to form Pangaeato form Pangaea Taconic orogenyTaconic orogeny Acadia orogenyAcadia orogeny Alleghenian orogenyAlleghenian orogeny Caledonian OrogenyCaledonian Orogeny Hercynian OrogenyHercynian Orogeny

Clues to PaleogeographyClues to Paleogeography

► Paleomagnetic evidencePaleomagnetic evidence► Lithologic evidenceLithologic evidence

► Limestone (shallow marine)Limestone (shallow marine)► Evaporites (equatorial dry conditions)Evaporites (equatorial dry conditions)► Lithic Sandstone and greywacke (mountain uplift)Lithic Sandstone and greywacke (mountain uplift)► Arkose (arid conditions)Arkose (arid conditions)► TillitesTillites► Quartz sandstoneQuartz sandstone► ShalesShales

Laurentia (N. America) and Laurentia (N. America) and Gondwanaland (first stage of Gondwanaland (first stage of

Pangaea )Pangaea )► GondwanalandGondwanaland

► formed in southern hemisphereformed in southern hemisphere► consists of S. America, Africa, and other shieldsconsists of S. America, Africa, and other shields► Drifter south to polar positionDrifter south to polar position

► LaurentiaLaurentia► Lay on equatorLay on equator► rotated counter clockwiserotated counter clockwise

Continental frameworkContinental framework

► Stable interiorStable interior► ArchesArches► SynclinesSynclines► BasinsBasins► DomesDomes

► Orogenic BeltsOrogenic Belts► Cordilleran MtnCordilleran Mtn► Franklin MtnFranklin Mtn► Appalachian MtnAppalachian Mtn► Caledonian mntCaledonian mnt

Paleogeography of Paleogeography of LaurentiaLaurentia

► Equator: North-central Mexico to Equator: North-central Mexico to Ellsmere Island, CanadaEllsmere Island, Canada

► Vast epeiric Sea (30o Latitude; Vast epeiric Sea (30o Latitude; vast carbonate deposits)vast carbonate deposits)

► Vast lowlands of Canada Shield Vast lowlands of Canada Shield were exposed (desert)were exposed (desert)

► Volcanic Mnts: Texas and New Volcanic Mnts: Texas and New EnglandEngland

SeawaysSeaways

► AppalachiansAppalachians (on east) (on east)► CordilleranCordilleran (on west) (on west)► FranklinianFranklinian (on north) (on north)► CaledonianCaledonian (on northwest) (on northwest)

Extensive Sediment beltsExtensive Sediment belts► Shales in seawaysShales in seaways► limestone in empieric seaslimestone in empieric seas► Quartz sand on shoreline and desertsQuartz sand on shoreline and deserts

Base of CambrianBase of Cambrian► Sedgwick’s original base (1835)Sedgwick’s original base (1835)

At top of nonconformity in WalesAt top of nonconformity in Wales At the first trilobite bearing At the first trilobite bearing

fossiliferous bedsfossiliferous beds Later dated at 560 myLater dated at 560 my

► New concept: Tommotian New concept: Tommotian Stage (1970)Stage (1970)

Base of Cambrian set at 570 myBase of Cambrian set at 570 my► New stage included fossiliferous New stage included fossiliferous

rocks above Vendian and some rocks above Vendian and some fossiliferous rocksfossiliferous rocks

► Fossils in new stage: Fossils in new stage: poriferaporifera, , brachiopodsbrachiopods, and organisms of , and organisms of unknown affinityunknown affinity

Cratonic Sequence of Cratonic Sequence of PaleozoicPaleozoic

► Sauk Sequence: Late Proterozoic to early : Late Proterozoic to early OrdovicianOrdovician

► Tippecanoe Sequence: Early Ordovician to : Early Ordovician to early Devonianearly Devonian

► Kaskakia Sequence: Early Devonian to : Early Devonian to end of Mississippianend of Mississippian

► Absaroka Sequence: Pennsylvanian to : Pennsylvanian to Early JurassicEarly Jurassic

Early Paleozoic HistoryEarly Paleozoic History

► Synopsis of Sauk TransgressionSynopsis of Sauk Transgression Canadian Shield eroded for 50 my prior to Canadian Shield eroded for 50 my prior to

transgressiontransgression

Gradual transgression covered shieldGradual transgression covered shield

Transcontinental Arch (highlands) became island Transcontinental Arch (highlands) became island chain in shallow epeiric seachain in shallow epeiric sea

Transcontinental Arch: Ontario to Mexico, parallel to Transcontinental Arch: Ontario to Mexico, parallel to Cambrian equatorCambrian equator

► As a Result:As a Result: Late Cambrian seas: MT to NYLate Cambrian seas: MT to NY Cordilleran deposits of Grand CanyonCordilleran deposits of Grand Canyon

► Tapeat SandstoneTapeat Sandstone (oldest) (oldest)► Bright Angel ShaleBright Angel Shale► Mauv LimestoneMauv Limestone (youngest) (youngest)

Time and Facies (Slight Time and Facies (Slight tangent)tangent)

► Bright Angel Shale: good example of Bright Angel Shale: good example of temporal transgression of faciestemporal transgression of facies

Early Cambrian (CA)Early Cambrian (CA) Middle Cambrian (AZ)Middle Cambrian (AZ)

Arches and BasinsArches and Basins

Back to the Sauk SequenceBack to the Sauk Sequence

► By the early By the early OrdovicianOrdovician sea regresses sea regresses and deposition endsand deposition ends

Vast continental-scale uncomformityVast continental-scale uncomformity KarstKarst topography on carbonates rocks topography on carbonates rocks

Tippecanoe SequenceTippecanoe Sequence

►Massive unconformity separates the Massive unconformity separates the Tippecanoe from the Sauk SequenceTippecanoe from the Sauk Sequence Known for:Known for:

► the “Super Mature” Sandstone, St. Peter Sandstonethe “Super Mature” Sandstone, St. Peter Sandstone What could “Super Mature” mean? What could “Super Mature” mean?

►Carbonate deposits contain abundant marine faunaCarbonate deposits contain abundant marine fauna

Fauna found in TippecanoeFauna found in Tippecanoe

► Shallow Marine limestones with vast Shallow Marine limestones with vast faunafauna

BrachiopodsBrachiopods BryozoansBryozoans EchinodermsEchinoderms MollusksMollusks CoralsCorals AlgaeAlgae

Close of the TippecanoeClose of the Tippecanoe

► Landlocked, reef-fringed basins develop in Landlocked, reef-fringed basins develop in Great Lake regionGreat Lake region

Evaporite regionEvaporite region

► In some areas evaporites accumulated to 750 In some areas evaporites accumulated to 750 metersmeters

If this occurred due to evaporation of a single body of If this occurred due to evaporation of a single body of water, the water would have to have been ~1000 water, the water would have to have been ~1000 kilometers deepkilometers deep

Barred Basin

Cordilleran Region HistoryCordilleran Region History

Sauk IntervalSauk Interval► Passive Margin on opening ocean; deep marine basin Passive Margin on opening ocean; deep marine basin

on weston west

► Western ocean opened; block rotated out; included Western ocean opened; block rotated out; included Siberian region of Asian continentSiberian region of Asian continent

► Arms of rift filled with thick sedimentsArms of rift filled with thick sediments Belt supergroup (MT, ID, BC)Belt supergroup (MT, ID, BC) Uinta Series (UT)Uinta Series (UT) Pahrump Series (CA)Pahrump Series (CA) Canadian Rockies (BC, Alberta)Canadian Rockies (BC, Alberta)

Tippecanoe IntervalTippecanoe Interval

► Conversion to active margin with subduction (Wilson Cycle)Conversion to active margin with subduction (Wilson Cycle)

► Volcanic Chain formed along western trenchVolcanic Chain formed along western trench

► Trench deposits; greywacke and volcanicsTrench deposits; greywacke and volcanics

► Western ocean deposits: Siliceous black shales and bedded Western ocean deposits: Siliceous black shales and bedded cherts with graptolites (graptolite facies)cherts with graptolites (graptolite facies)

► East of subduction zone: shelly facies- deposited in back East of subduction zone: shelly facies- deposited in back arch basins (fossiliferous carbonates)arch basins (fossiliferous carbonates)

Appalachian HistoryAppalachian History

► Appalachian Trough: Deformed three Appalachian Trough: Deformed three times during Paleozoictimes during Paleozoic

Subdivisions of trough:Subdivisions of trough:► Eastern sediment belt: greywacke, volcanic siliceous Eastern sediment belt: greywacke, volcanic siliceous

shaleshale► Western sediment belt: Shale, sandstone, limestoneWestern sediment belt: Shale, sandstone, limestone

Physiographic region of todayPhysiographic region of today► Eastern belt: Blue Ridge and PiedmontEastern belt: Blue Ridge and Piedmont

► Western Belt: Valley and Ridge and PlateauWestern Belt: Valley and Ridge and Plateau

Sauk IntervalSauk Interval

► Trough was a passive margin on opening oceanTrough was a passive margin on opening ocean Shelf sediments: sandstone and limestoneShelf sediments: sandstone and limestone Oceanic sediments: shalesOceanic sediments: shales

► Transgression spread deposits westward across Transgression spread deposits westward across craton; thick carbonates formed on subsiding shelfcraton; thick carbonates formed on subsiding shelf

► Abrupt end with onset of subduction and ocean Abrupt end with onset of subduction and ocean closure during Middle Ordovicianclosure during Middle Ordovician

Tippecanoe IntervalTippecanoe Interval

► Carbonate sedimentation ceased; platform downwarped by Carbonate sedimentation ceased; platform downwarped by subductionsubduction

► Thick Thick graptolitegraptolite black shale and shoreline immature sands black shale and shoreline immature sands spread westspread west

► Volcanic flows and pyroclastic beds formed when volcanoes Volcanic flows and pyroclastic beds formed when volcanoes emerged on coastemerged on coast

Rapid closing of eastern ocean (Iapetus); coastal and Rapid closing of eastern ocean (Iapetus); coastal and volcanic arc developedvolcanic arc developed► Millerburg Volcanic ash bed formed (454 my; 1-2 m thick)Millerburg Volcanic ash bed formed (454 my; 1-2 m thick)

Taconic OrogenyTaconic Orogeny

► Appalachian Mountains built in Appalachian Mountains built in collision with part of western collision with part of western EuropeEurope

► Compression folded shelf Compression folded shelf sediments into mnt and Logan’s sediments into mnt and Logan’s Thrust formed (48 km Thrust formed (48 km displacement)displacement)

Taconic OrogenyTaconic Orogeny

► Giant granitic Giant granitic batholiths produced batholiths produced by Taconic meltingby Taconic melting

Taconic Mountains Taconic Mountains weathered to form weathered to form vast sandstones of vast sandstones of PA, WY, OH, and NYPA, WY, OH, and NY► Great clastic Great clastic

wedges spread wedges spread westward (age westward (age tracts deformation)tracts deformation)

ClimatesClimates

► Transgressions= Mild Climates, windswept Transgressions= Mild Climates, windswept low terrainslow terrains

► Regressions and Orogenic Episodes= Regressions and Orogenic Episodes= Harsher more diverse climates; winds Harsher more diverse climates; winds diverted by mountainsdiverted by mountains

► Earth Rotation was faster (shorter days, Earth Rotation was faster (shorter days, greater tidal effects)greater tidal effects)

ClimateClimate

► No land PlantsNo land Plants Solar Radiation reflected, not absorbedSolar Radiation reflected, not absorbed Sever temperature differences resultingSever temperature differences resulting

► End of Late Proterozoic Glacial Cycle: Cool End of Late Proterozoic Glacial Cycle: Cool beginning for Early Paleozoicbeginning for Early Paleozoic

► Melting Polar Caps= Rising sea levels and Melting Polar Caps= Rising sea levels and warmingwarming

► Equitorial Position= tropical climates for Equitorial Position= tropical climates for Laurentia, Baltica, and AntarcticaLaurentia, Baltica, and Antarctica

► No Ice caps= warm polar seasNo Ice caps= warm polar seas

ClimateClimate

► Cross Bedding in Desert Sand Cross Bedding in Desert Sand Deposits Deposits Shows wind blew NE to SW across Shows wind blew NE to SW across

easterneastern

OrdovicianOrdovician

► Sea Levels and Biotic ExtinctionsSea Levels and Biotic Extinctions African Glaciation lowered sea levels African Glaciation lowered sea levels

and cooled global temperaturesand cooled global temperatures

End-Ordovician extinctions in many End-Ordovician extinctions in many familiesfamilies► BryozoansBryozoans► Tabulate coralsTabulate corals► BrachiopodsBrachiopods► SpongesSponges► Nautiloid cephalopodsNautiloid cephalopods► CrinoidsCrinoids

Silurian ClimateSilurian Climate

► Temperature Temperature ZonationZonation Glacial deposits Glacial deposits

above 65above 65oo latitude latitude Reefs, evaporates, Reefs, evaporates,

eolian sands below eolian sands below 4040oo latitude latitude

Late PaleozoicLate Paleozoic

►Devonian (480-360 m.y.a.)Devonian (480-360 m.y.a.)►Mississippian (360-320 m.y.a.)Mississippian (360-320 m.y.a.)►Pennsylvanian (320-286 m.y.a.)Pennsylvanian (320-286 m.y.a.)►Permian (286-245 m.y.a.)Permian (286-245 m.y.a.)

PangeaPangea

► During Silurian During Silurian IapetusIapetus sea closes - joins Baltica sea closes - joins Baltica and Lauretia (Caledonian Orogeny)and Lauretia (Caledonian Orogeny)

► Devonian-Orogeny continues to south forming Devonian-Orogeny continues to south forming LaurussiaLaurussia

► Pennsylvanian collision joins Gondwanna Land and Pennsylvanian collision joins Gondwanna Land and Laurussia (Hercynian in Europe, the Alleghenian in Laurussia (Hercynian in Europe, the Alleghenian in N. AmericaN. America

► By the Late Permian Pangea is completeBy the Late Permian Pangea is complete

Kaskaskia SequenceKaskaskia Sequence

►Oriskany sandstone- initial Oriskany sandstone- initial transgressiontransgression

►Devonian Clastics- material shed off Devonian Clastics- material shed off rising Appalachiansrising Appalachians

►Upper Devonian-MississippianUpper Devonian-Mississippian Massive marine depositsMassive marine deposits

►Late Mississippian- RegressionLate Mississippian- Regression Widespread erosion and development of Widespread erosion and development of

Karst topographyKarst topography

Absaroka SequenceAbsaroka Sequence

► Yet another transgressionYet another transgression► Unique cyclical sedimentsUnique cyclical sediments

CyclothemsCyclothems►ShaleShale►LimestoneLimestone►ShaleShale►LimestoneLimestone►CoalCoal

► Caused by either eustatic rise in sea level Caused by either eustatic rise in sea level (Glacial melting) or by subsidence.(Glacial melting) or by subsidence.

ClimateClimate

►Zonation paralled latitudeZonation paralled latitude Warm to hot within 40Warm to hot within 40oo of equator of equator

►Reduced COReduced CO22 in late Paleozoic causes in late Paleozoic causes cooling and then late Paleozoic Ice Agecooling and then late Paleozoic Ice Age

Mineral DepositsMineral Deposits

►Fossil FuelsFossil Fuels CoalCoal

►Present in all post Devonian rocksPresent in all post Devonian rocks

Oil and GasOil and Gas►Devonian Reefs Alberta, MT, SDDevonian Reefs Alberta, MT, SD►Appalachian basin PA, WVAppalachian basin PA, WV