Microfacies and palaeoecology of the Asmari Formation in southeast flank of the Khami anticline (east of Gachsaran) and Correlation with two other sections of the Asmari Formation in the Zagros Basin
Subject Areas :
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Keywords: Asmari Formation Microfacies Paleoecology East of Gachsaran,
Abstract :
Abstract In order to characterize the features of facies and depositional environment conditions of the Asmari Formation in southeast flank of the Khami anticline with a thickness of 270 m has been studied. the Field and laboratory studies, led to the identification 12 microfacies (nummulitidae lepidocyclina packestone/rodestone, corallinacea benthic foraminifera (perforate) packstone, bioclast neorotalia packestone, ooid grainstone, bioclast grainstone, miliolid neorotalia nummulitidae packestone, miliolid corallinacea coral floatstone/grainstone, bioclast benthic foraminifera (imperforate) packstone/grainstone, miliolid packstone/grainstone, sandy mudstone, intraclast mudstone) that deposited in continental slope, shoal, lagoon and tidal flat. In three different salinity facies environment from 34 psu to over 50 psu in oligoophotic to euphotic environment and oligotrophy-weak mesotrophy to eutrophy conditions in a homoclinal carbonate ramp platform recognized for the Asmari Formation at this study area. Correlation of the Asmari Formation in 3 section, A water salinity environmental correlation of the Asmari Formaion from Firozabad to east and north of Gachsaran reveals that 1- during Rupelian the Asmari Formation deposited in a normal water salinity environment, 2- while normal salinity water condition prevailed in Gachsaran area during Chattian, the Fars area was under higher marine salinity environment. Higher salinity environment developed during Aquitanian and Burdigalian in Gachsaran area.