نویسندگان
1 استادیار گروه زمینشناسی دانشگاه پیام نور، تهران، ایران
2 اداره اکتشاف شرکت ملی نفت، ص. پ. 6669-19395، تهران، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The Mand Limestone Member (MLM) is an informal name of an index lithostratigraphic unit in the central and eastern regions of Zagros fold-thrust belt, where the boundary of Middle-Late Jurassic coincides with the top of this unit. To determine depositional environments and depositional sequences analysis of the MLM in the southern Dezful Embayment, we integrated the geological and geophysical data obtained from two drilled wells in Chahar Bisheh and Milatun oil fields. The MLM in the studied wells is about 125 to 142 m thick and consists of two clean carbonate units (low gamma-ray pick) separated by a shaly horizon. We conducted petrographic investigations on 80 thin sections from cuttings and cored intervals. Our studies indicate an abundance of peloid/intraclast and ooid grainstones as the dominant microfacies accompanied by lime mudstones and skeletal wackestones with common pieces of foraminifera, green algae, and sponge spicules. Our findings are also compatible with the deposition of the Mand Member in different sub-environments on a homoclinal ramp including the oolithic shoal, lagoon, and open marine. The combination of stratigraphic data together with the wireline logs (gamma-ray and sonic) is consistent with a sequence stratigraphic framework, in which the lower part of the MLM comprises the HST of a 3rd order depositional sequence. We placed the TST and maximum flooding surface (MFS) in the Sargelu deep marine facies (Bajocian). Accordingly, the MFS represents the Callovian MFS J40 of southern Iran.
کلیدواژهها [English]
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