The geological history of pliocene-pleistocene evaporites in Mount Sedom (Israel) and how strontium and sulfur isotopes relate to their origin
- 139 Downloads
- 4 Citations
Abstract
Evaporites, comprising of gypsum, anhydrite and halite are described from the Pliocene Sedom Formation, the Caprocks units and the Pleistocene ‘Amora Formation in Mount Sedom, Southern Jordan Valley, Israel. Strontium and sulfur isotopic compositions of the evaporite minerals, and their Sr/Ca and Br/Cl ratios were used to interpret their environments of deposition and processes of formation and diagenesis. Some of the evaporites of the Sedom Formation were deposited from evaporated seawater. Others were deposited from a mixture of seawater and brines. The brines were composed of seawater which penetrated the carbonate rocks of the Rift margins, participated in dolomitization processes and, when hydrologic conditions allowed, seeped out into the Sedom basin and were mixed with evaporated seawater. These processes yielded non-homogeneous fluid masses of mixtures, as indicated by their wide range of87Sr/86Sr ratios (0.70824–0.70905) as compared to the narrow Sr/Ca ratios of the derived evaporites. Their marine origin is indicated by their δ34S values which are around 20‰ The evaporites of the ‘Amora Formation were precipitated from Ca-chloride brines only, which were originally evaporated seawater trapped in the Rift walls in the “Sedom Formation times”, returning to the Sedom basin after its disconnection from the sea. The high Sr content and Sr/Ca ratios indicate that the anhydrites existing today in the Sedom and ‘Amora formations were originally deposited from the evaporated seawater as gypsum which was later recrystallized at depth, at high pressures and temperatures. The caprocks are residual rocks of marine origin, formed by the dissolution of the exposed rock-salt units in the Sedom Formation. They represent mainly the gypsum (or anhydrite) beds intercalated in the rock-salt units of the Sedom Formation in Mount Sedom rather than Ca-sulfates disseminated in the halites.
Keywords
Gypsum Halite Anhydrite Evaporite Sulfur IsotopePreview
Unable to display preview. Download preview PDF.
References
- AGNON, A., 1983, An attempted revision of the Neogene stratigraphy in the Dead Sea Valley. Israel Geological Society, Annual Meeting Nazerat, Abstract, p. 1.Google Scholar
- BENTOR, Y.K. and VROMAN, A., 1960, The geological map of Israel, on a 1∶100,000 scale. Series A-The Negev. Sheet 16: Mt. Sdom., Geological Survey of Israel, 117 p.Google Scholar
- BERNER, R.A., 1971, Principles of chemical sedimentology. McGraw-Hill, 240 p.Google Scholar
- BERRY, L.G., ed., 1974, Selected powder diffraction data for minerals. Data Book. Joint Committee on Powder Diffraction Standards. Swarthmore, PA, USA, 833 p.Google Scholar
- BRAITSCH, O., 1971, Salt deposits, their origin and composition. Springer-Verlag, Berlin, 297 p.Google Scholar
- BURKE, R.E., DENISON, R.E., HETHERINGTON, R.B., KOEPNICK, H.F., NELSON, H.F., and OTTO, J.B., 1982, Variation of seawater87Sr/86Sr throughout Phanerozoic time:Geology, v. 10, p. 516–519.CrossRefGoogle Scholar
- CLAYPOOL, G.E., HOLSER, W.T., KAPLAN, I.R., SAKAI, H., and ZAK, I., 1980, The age curves of sulfur and oxygen isotopes in: Marine sulfate and their mutual interpretation:Chemical Geology, v. 28, p. 199–260.CrossRefGoogle Scholar
- COLEMAN, M.L. and MOORE, M.P., 1978, Direct reduction of sulfates to sulfur dioxide for isotopic analysis:Analytical Chemistry, v. 50, p. 1594–1595.CrossRefGoogle Scholar
- DEPAOLO, D.J. and INGRAM, B.L., 1985, High-resolution stratigraphy with strontium isotopes:Science, v. 227, p. 938–941.CrossRefGoogle Scholar
- FARRELL, J.W., CLEMENS, S.C., and GROMET, L.P., 1995, Improved chronostratigraphic reference curve of late Neogene seawater87Sr/86Sr:Geology, v. 23, p. 403–406.CrossRefGoogle Scholar
- FRIEDMAN, G.M., 1995, The arid peritidal complex of Abu Dahbi: a historical perspective:Carbonates and Evaporites, v. 10, p. 2–7.CrossRefGoogle Scholar
- FRIEDMAN, G.M., SNEH, AMIHAI, and OWEN, R.W., 1985, The Ras Muhammed Pool: Implications for the Gavish Sabkha, p. 218–237,in Friedman G.M. and Krumbein, W.F., Hypersaline Ecosystems: The Gavish Sabkha. Berlin, Heidelberg, New York, Tokyo, Springer Verlag, 484 p.CrossRefGoogle Scholar
- FRIEDMAN, G.M., SANDERS, J.E., and KOPASKA-MERKEL, 1992, Principles of Sedimentary Deposits — Stratigraphy and Sedimentology. New York, Macmillan Publishing Company, 717 p.Google Scholar
- FUGE, R., 1974, Bromine abundance in common igneous rock types.In Wedepohl, K.J., ed., Handbook of Geochemistry. Springer-Verlag, Berlin, II-4, 35E, p. 1–5.Google Scholar
- HERRMANN, A.G., 1961, Zur Geochimie des Sr in den salinaren Zechsteinablagerungen der Stassfurt-Serie des Suedharzbezirks:Chemie der Erde, v. 21, p. 137.Google Scholar
- HOLSER, W.T., 1979, Trace elements and isotopes in evaporites.In Burns, R.G., ed., Marine Minerals:Mineralogical Society of America, v. 6, p. 295–346.Google Scholar
- HOLSER, W.T. and KAPLAN, I.R., 1966, Isotope geochemistry of sedimentary sulfates:Chemical Geology, v. 1, p. 93–135.CrossRefGoogle Scholar
- KASHAI, A., 1988, An attempt to correlate larger stratigraphic units between the northern and southern parts of the Dead Sea-Jordan Rift system. Israel Geological Society Annual Meeting, ‘En Boqeq, Abstract, p. 59–60.Google Scholar
- KATZ, A. and BODENHEIMER W., 1962, The chemical analysis of rocks and minerals. The Hebrew University, Jerusalem. 150 p. (in Hebrew).Google Scholar
- KINSMAN, D.J., 1974, Calcium sulfate minerals of evaporite deposits: Their primary mineralogy.in Coogan, A.H., ed., Fourth symposium on salt. Houston, Texas. Northern Ohio Geological Society. v. 1, p. 481–496.Google Scholar
- LOEWENGART, S., 1962, The geochemical evolution of the Dead Sea basin:Bulletin of the Research Council, Israel, v. 11G, p. 85–96.Google Scholar
- MCCLUNE, W.F., ed., 1986, Mineral powder diffraction file. Data Book. International Center for Diffraction Data. Swarthmore, PA, USA, 1396 p.Google Scholar
- NIELSEN, H., 1979, Sulfur isotopes.In Jaeger, E. and Hunziker, J.C., 1979, Lectures in isotope geology. Springer Verlag, Berlin, p. 283–312.CrossRefGoogle Scholar
- RAAB, M., 1998, The origin of the evaporites in the Jordan — Dead Sea valley in view of the evolution of the brines and evaporites during seawater evaporation. Geological Survey of Israel Report GSI/1/98, 138 p. (in Hebrew, English summary).Google Scholar
- RAZ, E., 1983, The geology of the Judea Desert, En Geddi Region. Geological Survey of Israel. Unpublished Report 83/3/S, 110 p.Google Scholar
- SHEARMAN, D.J., 1963, Recent anhydrite, gypsum, dolomite, and halite from the coastal flats of the Arabian shore of the Persian Gulf. Proceedings of the Geological Society of London 1607, p. 63.Google Scholar
- STARINSKY, A., 1974, Relationship between Ca-chloride brines and sedimentary rocks in Israel. Unpublished Ph. D. thesis. The Hebrew University, Jerusalem. 176 p. (in Hebrew, English summary).Google Scholar
- STARINSKY, A. and BIELSKY, M., 1981, The strontium isotopic composition of saline waters along the Dead Sea Rift. 7th Europian Colloqium on Geochronology and Cosmochronology Jerusalem, Israel.Google Scholar
- STARINSKY, A., BIELSKY, M., LAZAR, B., STEINITZ, G., and RAAB, M., 1983, Strontium isotope evidence on the history of oilfield brines, Mediterranean Coastal Plain, Israel:Geochimica et Cosmochimica Acta, v. 47, p. 687–695.CrossRefGoogle Scholar
- STEIN, M., AGNON, A., STARINSKY, A., RAAB, M., KATZ, A., and ZAK, I., 1994, What is the “Age” of the Sedom Formation?. Israel Geological Society, Annual Meeting. Nof Ginossar. Abstract. p. 108.Google Scholar
- USDOWSKY, E., 1973, Das geochemische Verhalten des Strontiums bei der Genese und Diagenese von Ca-karbonat- und Ca-sulfat-Mineralen:Contributions to Mineralogy and Petrology, v. 38, p. 177–195.CrossRefGoogle Scholar
- WEINBERGER, R., 1992, Paleomagnetism in Mount Sedom, Israel: A method to determine the structure of the salt body and to reconstruct its emergence from the subsurface. Unpublished M. Sc. Thesis, The Hebrew University, Jerusalem. 101 p. (in Hebrew, English summary).Google Scholar
- ZAK, I. 1967, The geology of Mount Sedom. Geological Survey of Israel, Report. 208 p. (in Hebrew, English summary).Google Scholar
- ZAK, I., 1969, The Cl/Br ratio in rock salt: an indicator of the order of succession:Israel Journal of Earth Science, v. 18, p. 143–146.Google Scholar
- ZAK, I., 1974, Sedimentology and bromine geochemistry of marine and continental evaporites in the Dead Sea area.in A.H. Coogan, ed., Fourth Symposium on Salt. Houston, Texas. Northern Ohio Geological Society, v. 1, p. 349–361.Google Scholar
- ZAK, I., 1980, The geochemical evolution of the Dead Sea.in A.H. Coogan and L. Hauber, eds., Fifth Symposium on Salt. Hamburg, Germany. Northern Ohio Geological Society, v. 1, p. 181–184.Google Scholar
- ZAK, I. and FREUND, R., 1980, Strain measurements in eastern marginal shear zone of Mount Sedom salt diapir, Israel:American Association of Petroleum Geologists Bulletin, v. 64, p. 568–581.Google Scholar
- ZAK, I. and GRUDNIEWICZ, I., 1966, Geochemistry of evaporites and brines, Dead Sea basin.In: A.H. Coogan, ed., Fourth Symposium on Salt. Houston, Texas. Northern Ohio Geological Society, Abstracts. 2, p. 30.Google Scholar