© Mineral And Chemical Composition Of Karak Mudstone, Kohat Plateau, Pakistan: Implications For Smectite-Illitization And Provenance Saleemi, AA; Ahmed, Z ELSEVIER SCIENCE BV, SEDIMENTARY GEOLOGY; pp: ; Vol: 130 King Fahd University of Petroleum & Minerals Summary The Karak mudstone interbedded in an Eocene evaporite sequence, is dominated by R-1 ordered illite-smectite with a 20 to 30% expandable component. Minor phases include kaolinite, chlorite, illite/muscovite, plagioclase, potash feldspar, quartz, dolomite and pyrite. The present illite-smectite was probably originally smectite or highly expandable illite-smectite which underwent conversion to illite-smectite with a low expandable component in a comparatively low-temperature (ca.100 degrees C) closed-system sedimentary basinal diagenetic environment at a depth of ca. 5 km. Al3+ and K+ necessary for the conversion reaction were provided through the breakdown of potash feldspar. Burial under a 5 km thick pile of sediments produced some of the observed structures. Whole-rock chemistry presented here suggests that the mudstone formed by severe weathering of acidic source rocks. The influx of freshwater probably flushed out Ba, Rb, Ca and Mn from the restricted basin. (C) 2000 Elsevier Science B.V. All rights reserved. References: ABBASI IA, 1991, J STRUCT GEOL, V13, P319 AHMED MI, 1946, 272 NWFP GEOL SURV P BAKER DM, 1988, GEOLOGY, V16, P3 BIALEY SW, 1984, MICAS REV MINERALOGY, V13, P13 BROWN G, 1980, MIN SOC MONOGRAPH, V5, P305 BRUMSACK HJ, 1991, GEOL SOC LOND SPEC P, V58, P352 Copyright: King Fahd University of Petroleum & Minerals;

© CHAMLEY H, 1997, SOIL SEDIMENTS MINER CHAUDHRY MN, 1979, GEOL B PUNJAB U, V14, P1 CULLERS RL, 1975, GEOCHIM COSMOCHIM AC, V39, P1691 CULLERS RL, 1987, CHEM GEOL, V63, P275 DESEGONZAC GD, 1969, MEM SERV CARTE GEOL, V29 EBERL D, 1976, GEOL SOC AM BULL, V87, P1326 GARRELS RM, 1971, EVOLUTION SEDIMENTAR GEE ER, 1983, KASHMIR J GEOL, V1, P11 GOMBOS AM, 1995, SEDIMENT GEOL, V96, P119 GOVINDARAJU K, 1994, GEOSTAND NEWSL JUL, P18 GROMET LP, 1984, GEOCHIM COSMOCHIM AC, V48, P2469 HOWER J, 1976, GEOL SOC AM BULL, V87, P725 IZATT CN, 1990, THESIS IMPERIAL COLL JAMISON WR, 1987, J STRUCT GEOL, V9, P207 JAUME S, 1988, TECTONICS, V5, P57 KHAN MA, 1986, AAPG BULL, V70, P396 KRONBERG BI, 1979, CHEM GEOL, V24, P211 KUBLER B, 1997, SOIL SEDIMENTS MINER LATIF MA, 1970, WIEN JB GEOL BUNDESA, V15, P5 LILLIE RJ, 1987, CANADIAN SOC PETROLE, V12, P379 MCDOUGALL JW, 1991, AAPG BULL, V75, P463 MCDOUGALL JW, 1993, GEOL SOC LOND SPEC P, V74, P581 MEISSNER CR, 1974, 716D US GEOL SURV MEISSNER CR, 1975, 716F US GEOL SURV MILLOT G, 1964, GEOLOGIE ARGILES MOORE DM, 1997, XRAY DIFFRACTION IDE NAKAMURA N, 1974, GEOCHIM COSMOCHIM AC, V38, P757 NESBITT HW, 1979, NATURE, V279, P206 NESBITT HW, 1980, GEOCHIM COSMOCHIM AC, V44, P1659 NESBITT HW, 1982, NATURE, V299, P715 NORRY MJ, 1994, J GEOL SOC LONDON, V151, P195 PEARSON MJ, 1982, P INT CLAY C BOL PAV, P665 PEARSON MJ, 1988, CLAY MINER, V23, P109 PIVNIK DA, 1992, GEOL SOC AM ANN M, A53 PIVNIK DA, 1993, GEOLOGICAL SOC LONDO, V74, P559 RAMSEYER K, 1986, CLAY CLAY MINER, V34, P115 RAZA HA, 1981, GEOL B PUNJAB U, V16, P71 REYNOLDS RC, 1970, CLAYS CLAY MINERALS, V18, P25 REYNOLDS RC, 1980, MINERAL SOC MONOGR, V5, P249 SALEEMI AA, 1995, THESIS U LEICESTER SHAH SMI, 1977, MEM GEOL SURV PAK, V12 SRODON J, 1984, MICAS REV MINERALOGY, V13, P49 STEVENS MB, 1979, AM J SCI, V279, P129 TAYLOR SR, 1985, CONTINENTAL CRUST IT THOMSON M, 1989, HDB INDUCTIVELY COUP Copyright: King Fahd University of Petroleum & Minerals;

© WALSH JN, 1981, CHEM GEOL, V33, P141 WEAVER CE, 1960, AAPG BULL, V44, P1505 WEAVER CE, 1989, DEV SEDIMENTOL, V44, P819 WEDEPOHL KH, 1970, PHYS CHEM EARTH, V8, P303 WELLS NA, 1984, THESIS U MICHIGAN AN WILCOX RE, 1973, AAPG BULL, V57, P74 WRONKIEWICZ DJ, 1987, GEOCHIM COSMOCHIM AC, V51, P2401 WYNNE AB, 1875, MEM GEOL SURV INDIA, V11, P105 For pre-prints please write to: Copyright: King Fahd University of Petroleum & Minerals;