AGI DATA SHEETS FOR GEOLOGY IN THE FIELO, LABORATORY, ANO OFFICE Third Edition Compled by J.T. Dutro, Jr. R.V. Detrch R. M. Foose AMERICAN GEOLOGICAL INSTITUTE Copyright @ 1965, 1982, 1989 by the American Geologieal Institute 4220 King SI., Alexandria. VA 22302-1507 AII nghts reserved, No part 01 this publication may be reproduced, storad in a retrieval syslem, or transmitted in any form or by any means, electron,e, meehanieal, photocopying, reeording or otherwise, wthout prior wrtten permssion 01 he publisher, Llbrary 01 Congress Cataloging in Publlcation Data Maln entry under title: AGI data sheets: for geology in the feld, laboratory, and office, Compiled by J,T, Dulro. Jr., RY. Dietrieh, R,M. Foose. 3rd ed, p. cm Includas selselad, unehanged AGI data sheets from 1956-1964 se!' 1982 editlon, as well as rey, and new sheets. Bblography: p, ISBN 0-922152.01-2 1, Geology-Handbooks, manuals, etc, 1. Dulro, J. Thomas, Jr" 1923-, 11. Dietrieh, Richard Vineent, 1924-, 111. Foose, Richard Martn, 1915 IV American Geologieal Institule, QE52,A36 1989 550-dc20 89-32854 CIP Design and produClon by Melody Oakes. Mark Sehmidl, Bambi Satzer, Julie De Alley, and Martn Communealons, Ine, Primed on Allantlc Ledger Graentone by United Book Press, Inc, Frst Editon, 1965 Sacond Edition, 1982 Third Edition, 1989 Printed n the U.SA The Data Sheet series of Ihe American Geological Inslilule was conceived by Robert C. Slephenson, a former execulive director 01 AG!' In February of 1956, the tirsl Data Sheet, "Geologic Map Symbols 1," was published in the "Geological Newsletter" ot AG!' In July ot 1957, Joseph L GiIIson, then presidenl ot AGI, appointed a Data Sheet Commiltee wilh Richard M. Foose as chairman. The committee was given the responsibility of developing a series of Data Sheets to be pub ernployed are clted In SI81ger and Jager 11977) Rocks older than 570 m y also ca! led Precambrl an (pe). a [lme term w l hout spec tl,c rank Time ter ms wltnou! spec1hc r8nk. Note The 1983 edition by the U.S.G.S. Geologic Names Committee is essentially unchanged Irom this version , except lor incorporating the Precambrian Time Scale 01 Harrison and Peterman (see Data Sheet 1.3). AGI OS-td -B9 AGI DATA SHEET 1.2 REFERENCES Other geologlc time scales. Including internationally accepted epoch and terms, and detalls on boundanes, geochronalogy, and corre!atons can be in 1he following publicaVans. AAPG. 1978: Studles in Geology 6.388 p. Berggren. WA. 1972: Le/haia. v. 5. n 2. p 195-215. Evernden, J.F.. Savage, DE, Curtis, GH. and James. GT, 1964: Am. J. SeL. v. 262, p. 145198. Gao/. Soc London, J., v. 120S. 1964. 458 P Harland, WB.. and others. 1982. A Geo/agie Time Seale. Cambridge University Press. Cambridge. 131 p. Lambert RS, 1971: Geol. Soco London. SpeClal Publications 3. Part 1. p. 931. Monning. M., 1989: Eplsodes, V. '2. no. 1, p. 3-5. chan Palmer, A.R . 1983: Geo!ogy. v. 11, p. 503504. Odln, G.8., ed.. 1982. Numarieal Dating n Slratlgraphy. John Wiley and Sons, New York, 2 valumes. 1040 p Od,n, G.S , 1982: Episades. V. 1982, n. 3, p. 39. StelgBr. R.H., and Jager. E. 1977 Earth Planot. Sel. Le/!' v. 36. P 359-362. U.S. Geologic Names Committee. '983. U.s.G.S. Bu!!. 1537-A, p. Al-M. Age eslimales fo' the Phanerozolc are by GA. Izett, MA Lanphere. M.E MacLachlan, CW. Naeser, J.D. ObraaoVich. Z.E. Peterman, M. Rubln, T W. Stern, and R.E. Zarlman at the request 01 the Geologlc Names Commlltee. Age estimates lor the Precambnan are by the Inte'national Un'on 01 Geological Selmees Working Group on the Precambrian lar the United Stales and Mexlco. J.E Harrison, chairman {sea Data Sheet 1 3). AGI DATA SHEET 1.3 Precambrian Time Scale Jack E. Harrison and E. Peterman, U.S, Geotogical SUfvey EON ERA500 1000 U 5 N O 1500 a: W 1O a: a.. 2000 !/)a: -Z 2500 O :i ...J i z3000 45' dip toward upthrown block (illustrated); thrust laull has < 45' dlp loward D +65 overthrown block Strike separation apparent relativa movement In laul! strike 01 block opposlta the observer. R, rlght-Iateral lault; L, lel!lateral lault Dip and slrlke separatlons nearly equal. (A normal left-Iateral lault Is IlIustrated) Note: Letters Indlca!lng separation may be shown as approprlale and convenlent on elthar sida 01 the lault Irace. The symbOls (+) and (-) may be subslituled lor U and D bul none represents any componeni 01 slip. Separatlon symbols ara nol needed lor sectlons, and are only occaalonally necessary tor mapa because the dlsplacement 01 labular g9OIoglc units Is usually obvlous. known. Only those symbols used on a particular geologlc illustratlon need be shown In Ihe legend. Sea Data Sheet 3.3 tor addltonal tault symbols. AGI DATA SHEET 4.1 Symbols for Fluvial Nonmarine Sequences Tor H. Nllsen, San Carlos, Ca!lfornla Brecci a IOOQoJ Co nglamerate, O O O clast-supported IIII:JIIIA Conglomerate, matrix- supported 1_ - 1 Rip-up clasts, - shale or mudstone1 3 Rip-up clasts, (0) 0) sandstone 1< '-.: ': ' 1.0 to 2.0, are mosl common. This applies 10 relatlvely coarse-grained as well as 10 line-grained tephra. Median dameler, Mdq,: highly variable; coarser close lo source than larther away. Mdq:. IS commonly -1.0 lo -3.0d> (2 mm to 8 mm) or smaller (phi values) close lo source. Farther Irom source, Mdd> may vary Irom O.0d> (1 mm) lO 3.04> ('/B mm) or more. Composltlon Subaerial lephra composilion is mafic 10 slliclc, calc-alkaline lo alkaline, etc. Siliclc or intermediale fallOUI is more wldespread than maflc lallout because 01 usually greater explosivlty and volume 01 the eruptions, Inlermediate composillon is commonly assocated with large composile volcanoes. Malic composllion is commonly associated wllh cinder cones and extenslve lava flows, Bulk composilion gene rally becomes slighlly more silicc away from so urce due to eolian fractionation. Rock Associations and Facies Close to source (within vent or on steep volcano slopes): lava flows, pyroclastic flows, domes, pyroclaslic tuf! breccias, avalanche deposts, and debris Ilows. Inlermediate dslance to source: coarse-gralned tephra, some lava flows, pyrOclaSlc flows, ash lalls, and reworked fluvial deposlls, The coarser-grained pyrOclastic deposits gradually decrease, and reworked pyroclastic deposits gradually increase away from source. Far from source: airfall tephra, most easily recognized in marshy, lacustrine, windblown environments. Rock associations depend on environment 01 deposilion There are no relatad lava flows or coarse-grained volcaniclastics. AGI,DS-""l-I19 AGI DATA SHEET 26.2 SUBAQUEOUS TEPHRA Distribution and Thickness Dislribution 01 airfall pattern may be modilied by waler currenls -mosl often lo an irregular lan shape close lo source. Dislribulion tends lo beco me Ihicker loward source bul may be highly irregular. Thickness 01 single layers is commonly < 50 cm unless augmented by currenls in low places. Thick layers with many Ihin laminae may be multiple lall units. Structures Plan e parallel beds exlend over hundreds 01 km2. Normal grading s Irom cryslal and lilhicrich bases lo shard-rich tops. Basal conlacls are sharp; upper contacts diffuse due to reworking by burrowing animals. Structures may be inversely graded il pumice is present. Presence 01 abundant pumice suggesls restricted circulalion and is more common in lacustrine than in marine environments. Structures on land-based oulcrops may include post-depositional thickening, thinning, and flow slruclures, especially if diagenetically altered, or they may include water-escape structures and load or slump struclures. Textures Size and sorting parameters vary irregularly wilh distance from source but overall, size tends lo decrease. Sorting: good to poor depending upon amount 01 biolurbation. Inman sorting parameters, O'," generally > t.O,, and < 2.5w. Median diatneler, Md: comtnonly > 3.0 - fine-grained sand size and smaller. Composition Subaqueous lephra composilions range from matic lo silcic, wilh silicic ash mosl widespread. Composition is generally relaled lo composition 01 nearest volcanic sources. The Si02 conlent 01 glass shards may range 10 per cent wilhin a single layer. Bulk samples are more Si02-rich near top Ihan boltom 01 single layers because olgrading. Ancient layers in terrestrial geologic settings are typically altered to clays (dominantly monlmorillonite) and zeolites and are commonly known as bentonite (tonstein in Europe). Rock Associations and Facies Tephra is commonly interbedded with pelagic calcareous or siliceous oozes, or with terrigenous muds and silts depending upon proximily to land. Terrigenous materials are commonly turbidites. Ancient tephra layers on land are commonly interbedded wilh non-volcanic or tuffaceous shale or siltstone. Reference Fisher, R.V., and Schmincke, H.-U., 1984. Pyroclastc Rocks. Springer-Verlag, New York, 472 p. ____81___-_-..COMPOUND VOlCANO STRATO-VOlCANO COMPLEX VOlCANO (COMPOSIH VOLCANO) .-. ............... SOMMA VOlCANO CALDERA SHIElD VOLCANO ee ............. ~ l"'VA DOME CRATU ROW CINDU CONE TUFF CONE TUFF -RING MAAR FISSURE VEN T SCORIA CONE PUMICE CONE PYROClASTlC CONES - --Schematic profiles (vemcally exaggerated-2:1 shadad and 4:1 dark) from the data o, R.J. Pike (1978. Proc. 9th Lunar Planet. Sci. Cont., p. 3239-3273). Shapes and relativa sizes are only approximate. as dimensions vary within each group. lIIustration from Smithsonian publication VoIcanoesotthll W ~ 1981, Hutchinson Ross, Stroudsburg. Pa., 240 pp. More volcano data appears on Data Sheets 84.1-84.4. iI:"Oa ~ :D-a S "l1li ~al r-er 0'< m C)C) (;0-ter > mc.:...w _ :IJ 50 VEr 3 c: .... ~ ~ I 12" F.... T.... l o (5 zc:. z 50 VE I 2O ~ ~ ::: :! F _ L_____________ m 311 ....T.... L "':x: :IJOU ~c..< 50 VEI 1 r~ w o." _II...... ~ ~ ! 211 F.... T.... l L _____________c..! 50 VEITO _ (NON-EXPlOSIVE) 11 0 111 F ........ L _1 o 1 10 100 1000 10,000 INTERVAL BETWEEN ERUPTIONS (YEARSl Increased explosivily occurs wth longer eruption intervals. Data lor hislograms are from 4320 historie eruptions in which the time interval Irom the start 01 the previous eruption is known. These are grouped by Volcanie Explosivity Index (VEI, see Data Sheet 84.2). For eaeh group, the percentage 01 historie eruptions thal have caused fatalities is also shown. IlIustration from Smithsonian publication Vo/canoes of the Wor/d, 1981, Hutehinson Ross, Stroudsburg. Pa., 240 pp. AGI DATA SHEET 28.1 Graph for Determining the Size of Sedimentary Particles Data Sheet Commlttee, alded by George V. Chlllngar DARK PARTlCLES I d. = /0 mm d. = /5 mm Place sand grains or rock parti cles in the central part 01 the circle. Compare the size 01 the par ticles with those on the graph with the aid 01 a magnilyi ng glass. Record the corresponding number (1 , 2, 3, 4. 5. 6. 7.8) in notebook. For samples with parti cles 01 varying sizes, record the most common size lirst. Note: A comparator is available lo make size comparisons in the field and laboratory from Edmund Scientific Company, Barrington, New Jersey. AGIOs-M AGI DATA SHEET 28.2 L1GHT PARTICLES Relerences: (1) George V. Chilingar, 1956, Soviet classilication 01 sedimentary parti cles and Vasil'evskiy graph: AAPG Bull., v. 40, no. 7, p. 1714. (2) M.S. Shvetsov, 1948, Petrography 01 sedimentary rocks, 2nd ed ., 387 p. Gosgeolizdat, Moscow-Leningrad AGI DATA SHEET 29.1 Grainsize Scales By Roy L. Ingram. University 01 North Carolina GRAINSIZE SCALE USED BY AMERICAN GEOLOGISTS Modified Wentworth Scale - after Lane, et al., 1947. Trans. American Geophysical Un ion, v. 28, p. 936-938 GRADE LlMITS phi mm mm mehes--_....---12 4096 161.3 -11 2048 80.6 -lO 40.3 -9 512 256 lO. 1 5.0 -6 64 2.52 1.26 -4 16 032 0.16 -1 008 0.04 +1 +2 1/4 0.250 li8 0.125 +4 1/16 0.062 +5 1/32 0.031 1/64 0,016 +7 11228 0008 1/256 0.004 +9 0.002 -1-10 1/1024 0001 1/2048 0.0005 AGIDSrvd-82 rnrn 31.5mrn 16rnm 8rnm NO.5 No. 10 No. 18 No. No. 60 No. 120 No. GRADE NAIv1E very large large BOLlders medium srnall large Cobbles GRAVEL very coarse rnediurn Pebbles fine very fine verycoarse rned,um Sand SAND fine veryfll1e rnediurn very fine Iv1UD rned,urn Clay size fine very fine AGI DATA SHEET 29.2 GRAINSIZE SCALE USEO BY ENGtNEERS (A.S.T.M. Standards 0422-6_3_;0_64_3_-_18.-'-)____ GRADE LI MITS GRADE NAME Boulders 305 12.0 Cobbles 76.2 3.0 3.0 in. ~ . - .....--Gravel 4.75 0.19 - No. 4 coarse 2.00 0.08 No. 10 medium Sand 0.425 No. 40 fine - 0.074 .. No. 200 Silt 0.005 ... ~ .. ~ - - .... _ .. -----...... GRAINSIZE SCALE USEO BY SOILS SCIENTISTS U.S. Dept. 01 Agriculture, Agriculture Handbook No. 436 (1975) GRADE LlMITS ------G ~ A D E NAME -76.2--3.0 2.0 0.08 75mm No. 10 ~ -Gravel 1.0 0.04 No. 18 very coarse 0.500 No. 35 coarse 0.250 No. 60 medium Sand 0.100 No. 140 fine 0.050 -0.002 No. 270 very fine Silt AGI DATA SHEET 29.3 SIEVES FOR DETAILED SIZE ANALYSIS -4.0 16.000 -3.75 13.454 -3.50 11.314 -3.25 9.514 -3.00 8.00 -275 6.727 5.657 -2.25 4.757 -2.00 4.000 -1.75 3.364 -150 2.828 -125 2.378 -1.00 2.000 -0.75 1.682 -0.50 1.414 -0.25 1.189 0.00 1.000 0.25 0.841 0.50 0.707 0.75 1.00 0.500 1.25 0.420 1.50 0.354 1.75 0297 2.00 0250 2.25 0210 2.50 0.177 2.75 0.149 3.00 0.125 3.25 0.105 0.088 3.75 0.074 4.00 0.062 4.25 0.053 4.50 0.044 16.0 13.2 11.2 95 8.0 6.7 5.6 4.75 4.00 3.35 2.80 2.36 200 1.70 1.40 1.00 0.850 OllO 0.600 0.500 0.425 0.355 0.300 0.250 0.212 0.180 0.150 0.106 0.090 0.075 0.063 0.053 0.045 6 7 8 10 12 14 16 18 20 25 30 35 40 45 50 60 70 80 100 120 140 200 230 325 AGI DATA SHEET 30.1 Comparison Chart for Estimating Roundness and Sphericity Maurlce C. Powers, Elizabeth City StBte Universlty This sheet showing both sphericity and roundness suggests that particle shapes that initially break out or weather Irom parent rocks tend to be either discoidal, rodlike (prismatlc), or spheroidal. It lurther suggests that as the particles are reduced in size by abraslon andlor chemical weathering they tend to assume more nearly spherical shapes. This, 01 course, is not invariably true, but it is the evolutionary process to be ex pected. The chart below incorporates median rho values lor roundness and sphericity. as suggested by Folk (1955). because 01 the ease 01 handling these values statistically. and because they represent midpoints 01 each roundness and sphericity class. Alter determining Irequency and cumulative percents lor roundness and sphericily classes. each may be plotted as histograms or as cumulative curves on probability paper. Such plots give a visual relerence lor samples under examination and afford an opportunity to carry out statisticl nrocedures. "'GIOS-rvd-89 AGI DATA SHEET 30.2 This chart has the following advantages over other charts such as the one given on the 1953 AGI Data Sheet 1. Most sedimentary particles between sand and cobble size wlll appear similar to one of the particles iIIustrated. 2. When a "match" or near match has been found, the investigator has simultaneously determined the roundness, the sphericity, and the general shape lerm that describe the particle. 3. 4. Relationships belween roundness and sphericity populalions and Ihe fluid dynamics or aerodynamics 01 a transporting medium may be investigated. Experience indicates thal at leasl fifty grains from a sample should be examined in order lo arrive al valid average values. Allhough the fluid dynamics involving particles of differenl shapes and varying parti cle slze Is rather complex, it appears lo blend for slzes smaller than 2 phi, even if they have differenl shapes. abraded lo more nearly spherlcal formS.Excellent examples of highly spherical lour malines and zircons can be found in the Carmel formation of southeastern Utah. Wllh the exceptlon of certain phyllosilicates that tend to retain thelr discoidal shapes even as extremely smallsized partlcles, discoidalshaped mineral grains may lollow a similar sequentlal shapin, thus also eventually becoming spheroldal. It Is noteworthy in Ihis respect that fine micas as well as clay mlnerals (both groups are phyllosillcates) commonly form "fine partlngs" in shales and even In fine sandslones and sillstones. For particles larger than 2 phi, the effect of grain shape on fluid dynamics or aerodynamlcs Is more compllcated. Allhough discoidal shapes have greater surface area per unlt volume than other shapes, they tend to be imbrlcaled on sedlment floors, an arrangement which effectlvely streamlines the particles and makes them relatlvely stable wlth respect to curren! acllon. Rods have less surface area par unit volume than discs, bu! tend lo roll rather easily wlth their long axes essenlially perpendicular to curo rents. Spheres have less surface area than other shapes and roll easily on plaln Sur faces; spheres, however, are rather easlly entrapped in pockets and other irregularities on sediment surfaces and thus may be removed from the transpor! load. References Barrett, P .J., 1980, Tha shape 01 rock particlas, a critical reviaw: Sedimentology, v. 27, p. 291-303. Dobkins, J.E., and Folk, R.L, 1970, Shape davelopment on Tahiti-nui: J. Sediment. Pet., v. 40, p.11561203. Doyle, LJ., Carder, K-L, and Steward, R.G., 1983, The hydraulic equivalence 01 mica: J. Sedimento Pet., v. 53, p. 643-648. Els, B.G., 1988, Pebble morphology 01 an anclent conglomerate: the Middelvlei gold placer, Witwatersrand, South Africa: J. Sedimento Pet., V. 58, p. 894-901. Folk, R.L, 1955, Student operator error in deterrnination of roundness, sphericlty and grain slze: J. Sedimento Pet., V. 25, p. 297-301. Komar, P.D., Baba, J., and Cul. B., 1984, Grainsize analyses 01 mica within sediments and the hydraulic equivalence 01 mica and quartz: J. Sedimento Pet., v. 54, p. 1379-1391. Krumbein, W.C., 1941, Measurements and geologic signiflcance 01 shape and roundness 01 sedlmenlary particles: J. Sedimento Pet., V. 11, p. 64-72. Landon, R.E., 1930, An analysis 01 beach pebble abrasion and Iransportation: J. Gso!., V. 38, p. 437446. AGI DATA SHEET 30.3 McBride, E.F., and Picard, M.O., 1967, Downstream changes in sand composition, roundness, and size in a short-headed, high gradient stream, Northwest Italy: J. Sedimento Pet, V. p.l016-1026. Milis, H.H., 1979, Downstream rounding of pebbles a quantitative review; J. Sediment. Peto v. 49, p. 295-302. Powers. M.C., 1953, A new roundness scale lor sedimentary partides: J. Sediment. Pet., V. 23. p. 117-119. Sneed, E.D., and Folk, R.L., 1958, Pebbles in the lower Colorado River, Texas, a study in particle morphogenesis: J. 6eol., v. 66, p. 114-150 Visher, G.S., 1969, Grain size distributions and depositional processes: J. Sedimento Pet., V. 39. p. 1074-1106. Waag, C.J., and Ogren, DE, 1964, Shape evolution and fabric in a boulder beach, Monument Cove, Maine: J. Sedimento Pet., V. 54, p. 96-102. AGI DATA SHEET 31.1 Descriptive Terms for Megascopic Appearances of Rack and Particle Surfaces Compiled by Maurice C. Powers, Elizabeth CUy Slale University [Most delinitions are slightly revised versions 01 those in the A.G.!. "Glossary 01 Geology" (2nd ed.)] Burnished surlace-Megascopically indistinguishable Irom polshed and sorne varnished surlaces. Polished surfaces are marked by extremely fine scratches lormed by surlace abrasion whereas burnished surlaces result Irom more nearly random removal 01 multimolecular sized pieces to lorm a nearly Ilat surface. Chattermark-One 01 a series 01 small, closely spaced, short curved scars or cracks brittle rock surlace by rock Iragments car Crescentic gouge-A crescentic mark in the form 01 a groove or channel with a sorne what roundad bottom; it is lormad by the removal 01 rock material from between two Iractures; it is concave toward the direction from which the ice moved (Le., its "horns" point in the direction 01 ice movement). Desert varnish-A thin dark shiny lilm or coating, composed 01 iron oxide commonly accompanied by traces 01 manganese oxide and silica, formed on the surlaces 01 pebbles, boulders, and other rock Iragments in, lor example. desert regions alter long exposure. It is believed to be causad by exudation 01 mineralized solutons lrom within and deposition by evaporation on the surlace. A similar appearance produced by wind abrasion is known as desert polish. Syn: desert patina; desert lacquer; desert crust; desert rind; varnish. curved laces intersecting in three Dull luster-The luster 01 a mineral or rock surface that difluses rather than reflects light, even though the surlace may appear smooth (c.f. (rosted surlaee, matte sur faee). Einkanter-A ventilact having only one lace or a single sharp edge. Etched-A naturally eorroded surlace 01 a mineral or rock with the erystal or structural pattem enhanced lor observation beeause 01 differences in reliel. Faeet-A nearly plane surlace produeed on a roek Iragment by abrasion. as by wind sandblasting, by the grinding aetion 01 a glacier, or by a stream thal differentially removes material Irom the upstream side 01 a boulder or pebble. Frosted surlaee-A lusterless groundglasslike surlaee on roundad mineral grains, espeeially 01 quartz. It may result Irom innumerable impaets 01 other grains during wind aetion, lrom chemieal aetion, or Irom deposition 01 many microscopie erystals, lor example, 01 line silica seeondarily deposited on quartz grains (e.1. matted sur faee). Groove-A low area between two ridges; a linear depression 01 whieh lhe length greatly exeeeds lhe width. A groove is larger than a striation. Matte(d) surlace-An evenly roughened surfaee (c.f. frosted surfaee). Pereussion mark-A ereseentie sear produeed on a hard, dense roek (e.g., chert or quartzite) by a sharp blow, as by the violen! collision 01 a eobble with a boulder in a streambed. Pitted surlaee-Marked eoncavities not related to the eomposition or texture 01 the rock on which they appear. The depressions range in size Irom minute pits eaused by dust partieles to those that are a lew eentimeters aeross and a lew eentimeters deep. Polished surlace-Charaeterized by high luster and strong relleeted light.lt may be pro dueed by various agents, e.g., desert varnish or abrasion by glacial Ilour (e.l. bur nished surfaee). Seored surlaee-Parallel seratehes, striae, or grooves on a badroek surlaee eaused by the abrasion aetion 01 roek Iragments transportad by, lor example, a moving glaeier. Serateh-See groove, scored surfaee, and striated surlace. Striated surlaee-Surlaee marked by fine lines or seratehes, generally parallel or sub parallel to eaeh other. Surfaee luster-The appearanee 01 a surlaee in reflectad light, generally deseribed by its quality and/or intensity. For example, metallie versus nonmetallie and bright ver susdull. Varnlsh-See desert vamish. AGIDSrvd82 AGI DATA SHEET 32.1 Names for Sedimentary Rocks Condensed by A.R. Compton trom Manual of Fleld Geology, John Wiley and Sons, New York,1956 ..(1)/,, /)VI> '" J:: '" :S lo i V&"J6Jo '" -; i;i o o '"