Biostratigraphy, sedimentary environment and sequence stratigraphy of the Asmari Formation in well no. 4 of Lab-e Safid oil field (north of Dezful embayment, SW of Lurestan) and Tang- e Lendeh (Kuh-e Safid, NW of Dehdasht)

In this research biostratigraphy, microfacies, sedimentary environment and sequence stratigraphy of the Asmari Formation in well no.4 of Lab-e Safid (north of Dezful embayment, SW of Lurestan) and Tang- e Lendeh (Kuh-e Safid, NW of Dehdasht) has been studied. The total thickness of the Asmari Formation is 360 m and 260 m in the Lab-e Safid and Tang- e Lendeh sections, respectively and composed of thick, medium and thin bedded limestone. The correlation of recognized biozones in the studied regions with other regions in Zagros (Bangestan Anticline: tang-e Band, tang-e Nayab and Tang-e Bulfares, Parsi oil field, Kuh-Asmari and Khaviz Anticline: Tang-e Bibinarjes) indicates that Asmari Formatin in Tang-e Bibinarjes, Tang-e Band and, well no.4 of Lab-e Safid has deposited earlier than other regions. Four different sub environments were identified in the Asmari Formation based on microfacies analysis including tidal flat, lagoon, shoal, open marine. These depositional environments correspond to inner, middle and outer ramp. On the basis of deepening and shallowing patterns in the microfacies five and two third-order sequences have been recognized in the Lab-e Safid and Tang- e Lendeh sections, respectively. In order to study the changes of depositional environment of the Asmari Formation during the Oligocene-Miocene, the recognized sequences in this study have been correlated with those recognized in other parts of the Zagros basin.