Basin Analysis and Paleogeography of the Zagros Foreland Basin during the Maastrichtian,High Zagros Basin,Iran

A sedimentological investigation was carried out to reconstruct the paleogeography of the Zagros Foreland Basin.Based on the study of more than 1000 rock samples,nine carbonate microfacies and three terrigenous facies were identified.The study reveals that the Maastrichtian succession was deposited in a widespread homoclinal ramp in the High Zagros Basin.Three(Gandom Kar area),two(Ardal area),seven(Gardbishe area),five(Shirmard area),two(Kuh-e-Kamaneh area),three(Kuh-e-Balghar area),and six(Murak area)of depositional sequences(3rd order)were identified.The thickness of the lowstand systems tract(LST)due to activities of local faults and subsidence in the southeast is more than in the central and northwest of the High Zagros Basin during the Early and Early Middle Maastrichtian.During the Middle Maastrichtian,the shallow and deep marine deposits were formed during the transgressive systems tract(TST)and highstand systems tract(HST)in this basin and the rate of subsidence in the center of this basin(Gardbishe area)is higher than in other areas and the platform was drowned in this area.The falling relative sea-level due to activities of local faults led to that marine deposits were absent in all parts of the High Zagros Basin(except the south part)during the Late Maastrichtian.Paleogeographical studies on the Zagros Basin during the Late Campanian-Maastrichtian showed the following results:shallow marine environments were developed in the southeast of this basin,and the turbidite,delta,and fluvial environments in the northwest were developed more than in other areas.