Writers : Morteza Sheikh; Supervisor: Dr. Yaghoob Lasemi; Consulting Supervisor: Dr. Seyed Ali Aghanabati
Refference : Msc. Thesis
Publishing Year : 1387

Abstract :

The Shirgesht Formation (Lower- Middle Ordovician) in the area northwest of Tabas is 925 meters thick and consists of three members. Its lower boundary with the Derenjal Formation is transitional and It s upper boundary with the Niur Formation is disconformable.
Field and microscopic studies of the Shirgesht Formation led to recognition of a group of deep marine facies including turbidity and basin plain facies. The turbidity facies of the Shirgesht Formation were originated from the erosion of older formations (Lalun, Zagun & Derenjal Formations). They were deposited in a shallow marine environment and retransported to deep marine setting. The basin plain shale facies was deposited over the turbidity facies at times of quiet water condition.
The turbidity and basin plain facies of the Shirgesht Formation indicate deposition in a relatively deep marine environment (submarine fans and basin plain) suggesting the slope needed to generate turbidity currents.

Subject List : Depositional environment