Late Jurassic-Late Permian dolomites in central Saudi Arabia: Ca:Mg stoichiometry and Sr-content
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A difference in the depositional environments of the Upper Permian and the Upper Jurassic carbonate rocks exposed in central Saudi Arabia led to a difference in the initial dolomite geochemistry; i.e. Ca: Mg stoichiometry and Sr-content.
The Khuff dolomites are characterized by: (i) well-ordering (high R-value) (ii) stoichiometric nature (with an average CaCO3 of about 1 mole %) (iii) and low Sr-content (from 55 ppm to 183 ppm) relative to Holocene marine dolomites. The Khuff carbonates were deposited in a sabkha-like, hypersaline environment, where the increased salinity favored the precipitation of a better-ordered and more stoichiometric dolomite than would be expected to form had the dolomites formed in a normal marine environment. Later recrystallization of the Khuff dolomite also may have increased the degree of ordering in the dolomites. The low strontium content in the Khuff dolomite could have been due to depletion during diagenetic modification of the initially precipitated non-ideal Khuff dolomite.
Jubaila carbonates were formed in a normal marine environment, where the source of Mg+2 responsible for the dolomitization of its upper part is related to the prograding of the supratidal sabkha front formed at the terminal Jubaila stages. The Jubaila dolomites are relatively poorly ordered with a CaCO3 content of 7 mole % and an average Sr-content of 241 ppm.
KeywordsDolomite Jurassic Anhydrite Evaporite Grainstone
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- AL-JALLAL, I.A, 1987, Diagenetic effects on reservoir properties of Permian Khuff Formation in eastern Saudi Arabia:Society of Petroleum Engineers:1574, p. 465–475.Google Scholar
- AL-JALLAL, I.A., KAMAL, R.A., and McCLURE, H.A., 1987, Sedimentary features of the Permian Khuff Formation, a fossil analog to Quaternary Arabian Gulf depositional environments: Presentation on conference on Quaternary sediments in the Arabian Gulf and Mesopotamian Region, Kuwait.Google Scholar
- AL-SHARHAN, A.S., and KENDALL, C.G.ST., 1986, Pre-Cambrian to Jurassic rocks of Arabian Gulf and adjacent areas: their facies, depositional setting, and hydrocarbon habitat:American Association of Petroleum Geologists Bulletin, v. 70, p. 977–1002.Google Scholar
- BAKER, P.A., and BURNS, S.J., 1985, Occurrence and formation of dolomite in organic-rich continental margin sediments:American Association of Petroleum Geologists Bulletin, v. 69, p. 1917–1930.Google Scholar
- BASYONI, M.H., 1984, Sedimentology and stratigraphy of the northern Khuff Formation, Saudi Arabia. Ph.D. thesis, University of East Anglia, Norwich, United Kingdom.Google Scholar
- BASYONI, M., ZEIDAN, R.H., and BANAT, K.M., 1992, Petrographic and geochemical properties and related economic potential of the Khuff and Jubaila carbonates in central Saudi Arabia. King Abdul Aziz University sponsored project no. 577/408, (unpublished report).Google Scholar
- CARBALLO, J.D., LAND, L.S., and MISER, D.E., 1987, Holocene dolomitization of supratidal sediments by active tidal pumping, Sugarloaf Key, Florida:Journal of Sedimentary Petrology, v. 57, p. 153–165.Google Scholar
- FÜCHTBAUER, H., 1974, Sediments and sedimentary rocks 1. John Wiley and Sons, New York, 464 p.Google Scholar
- LAND, L.S., 1980, The isotopic and trace elements geochemistry of dolomite,in Gao, G. and Land, L.S., Nodular chert from the Arbuckle Group, Slick Hills, SW Oklahoma: a combined field, petrographic and isotopic study:Sedimentology, v. 38, p. 857–870.Google Scholar
- LUMSDEN, D.N., and CHIMAHUSKY, J.S., 1980, Relationship between dolomite nonstoichiometry and carbonate facies parameters,in Peryt, T.M and Magaritz, M., Genesis of evaporite-associated platform Dolomite (Zechstein, Upper Pemian), Leba elevation, Northern Poland:Sedimentology, v. 37, p. 745–761.Google Scholar
- MARSCHNER, H., 1968, Ca−Mg distribution in carbonates from the Lower Keuperin NW Germany,in Sperber, C.M., Wilkinson B.H., and Peacor, D.R., Rock composition, dolomite stoichiometry and rock/water reactions in dolomitic carbonate rocks:Journal of Geology, v. 92, p. 609–622.Google Scholar
- MULLER, G., 1967, Methods in sedimentary petrology. Hafner Publishing Company, New York, London, 283 p.Google Scholar
- POWERS, R.W., RAMIRES, L.F., REDOND, C.D., and ELBERG, E.L., 1966, Geology of the Arabian Pen-insula: Sedimentary Geology of Saudi Arabia:US Geological Survey Professional paper 560D, 147 p.Google Scholar
- SCOFFIN, T.P., 1987, An introduction to carbonate sediments and rocks. Blackie Company Publising, New York, 274 p.Google Scholar
- VEIZER, J., 1983, Chemical diagensis of carbonates: theory and application of trace element technique,in Wallance, M.C., Origin of dolomitization on the Barbwire Terrace, Canning Basin, Western Australia:Sedimentology, v. 37, p. 105–122.Google Scholar
- ZEIDAN, R.H., 1981, Sedimentology and diagenesis of the Upper Jurassic Jubaila Limestone in Central Arabia. Ph.D. thesis, University of Leeds, United Kingdom.Google Scholar