Study of Facies, Sedimentary Paleoenvironment and Biostratigraphy of Guri Member (Mishan Formation) in SE of Jahrum, Zagros

The studied section (Guri Member) is located at Mansour-Abad area, SE of Jahrum. This section, with a thickness of 175 m, consists of cream, thin to medium bedded limestone and gray marl. The lower boundary with green marls and red silts of Razak Formation is conform and the upper boundary changes gradually to Mishan Formation.
The thin sections and washed samples studies lead to recognition of 40 genus and 21 species of foraminifers. Based on the association of index species such as Operculina complanata, Neorotalia vennotti and Miogypsinoides dehaariti an assemblage biozone number 1 was recognized Operculina-Nephrolepidina-Miogypsina assemblage zone.
which is the compareable with biozone- 64 of Wynd.
The red alga Lithophyllum sp. was also recognized. Based on the foraminiferas, the age of Guri Member in the studied section was determined as Aquitanian- Burdigalian.
Based on Facies and sedimentary environment, 13 micofacies were recognized which have been deposited in three environments- outer, mid, and inner ramps, and can be referred to restricted marine, shoal, lagoon and tidal flat. Therefore, the sedimentary environment of Guri Member is a carbonate platform of a homoclinal ramp which begins from the coast, then crosses a bioclastic barrier and ends in semi-deep marine environment.