Salinity Changes of Asmari Formation, Implication on Sedimentary Facies and Benthic Foraminifera in N.W Central Zagros Basin

Abstract

The salinity changes of Asmari Formation is based on the paleoenvironmental analysis of the depositional facies in the Ghale Nar Oilfield in the N.W central the Zagros fold-thrust belt. Salinity conditions are interpreted from analogy with the modern salinity gradient in Shark Bay, Western Australia, and the time scale is derived from foraminiferal biozonpaleoenvironmentation. The study demonstrates that frequent changes took place in  the sedimentary facies and salinity conditions in the central Zagros Baisin during the Chattian, Aquitanian, and Burdigalian. A transition took place from normal marine to hypersaline conditions following a significant shallowing from the middle ramp zone to the innermost part of inner ramp zone during the late Chattian. Episodes of severe hypersalinity (>70 psu) occurred in the Chattian- Aquitanian and Aquitanian -Burdigalian borders which is characterized by the presence of primary dolomite and anhydrite.

Keywords


منابع
 
 
 
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