TY - JOUR
T1 - The geological history of messinian (upper miocene) evaporites in the central Jordan Valley (Israel) and how strontium and sulfur isotopes relate to their origin
AU - Raab, M.
AU - Friedman, G. M.
AU - Spiro, B.
AU - Starinsky, A.
AU - Zak, I.
PY - 1997
Y1 - 1997
N2 - Evaporites, comprising gypsum, anhydrite, halite and dolomite are described from the Messinian Bira Formation outcrops and from two boreholes (Newe Ur-2 and Zemah-1) in the Central Jordan Valley, Israel. Strontium and sulfur isotopic compositions of the evaporite minerals, and their Sr/Ca and Br/Cl ratios are used to interpret their environments of deposition and processes of formation and diagenesis. The brines from which the evaporites precipitated originated from seawater. The processes caused by mixing of surface water, seawater and subsurface brines, resulted in dolomitization and also sulfur reduction. The surface water and subsurface brines reacted with the rocks they drained, including Cretaceous and Eocene carbonates and Neogene basalts. The gypsum deposits in the Central Jordan Valley are interpreted to have formed as a result of evaporation of the magnesium-rich Lake Bira water which became oversaturated with respect to calcite and gypsum. The gypsum was deposited in stratified, relatively closed basins, where a partial reduction of the sulfur resulted in high δ34S of the precipitated gypsum. Gypsum and early diagenetic dolomite formed from the same water bodies. The Bira evaporites in Newe Ur-2 borehole, precipitated from mixtures of sea- and fresh waters with basaltic contribution. The samples from the Lower Gabbro and Halite Unit in the Zemah-1 borehole were deposited from evaporated seawater, which leached basaltic rocks, in closed basins; the Middle Halite Unit formed from seawater, whiles the brines that deposited the Upper Halite Unit leached also basalt rocks.
AB - Evaporites, comprising gypsum, anhydrite, halite and dolomite are described from the Messinian Bira Formation outcrops and from two boreholes (Newe Ur-2 and Zemah-1) in the Central Jordan Valley, Israel. Strontium and sulfur isotopic compositions of the evaporite minerals, and their Sr/Ca and Br/Cl ratios are used to interpret their environments of deposition and processes of formation and diagenesis. The brines from which the evaporites precipitated originated from seawater. The processes caused by mixing of surface water, seawater and subsurface brines, resulted in dolomitization and also sulfur reduction. The surface water and subsurface brines reacted with the rocks they drained, including Cretaceous and Eocene carbonates and Neogene basalts. The gypsum deposits in the Central Jordan Valley are interpreted to have formed as a result of evaporation of the magnesium-rich Lake Bira water which became oversaturated with respect to calcite and gypsum. The gypsum was deposited in stratified, relatively closed basins, where a partial reduction of the sulfur resulted in high δ34S of the precipitated gypsum. Gypsum and early diagenetic dolomite formed from the same water bodies. The Bira evaporites in Newe Ur-2 borehole, precipitated from mixtures of sea- and fresh waters with basaltic contribution. The samples from the Lower Gabbro and Halite Unit in the Zemah-1 borehole were deposited from evaporated seawater, which leached basaltic rocks, in closed basins; the Middle Halite Unit formed from seawater, whiles the brines that deposited the Upper Halite Unit leached also basalt rocks.
UR - http://www.scopus.com/inward/record.url?scp=0031400710&partnerID=8YFLogxK
U2 - 10.1007/BF03175424
DO - 10.1007/BF03175424
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AN - SCOPUS:0031400710
SN - 0891-2556
VL - 12
SP - 296
EP - 324
JO - Carbonates and Evaporites
JF - Carbonates and Evaporites
IS - 2
ER -