[1] The formation dates to the Oligocene and Miocene periods and is a major hydrocarbon reserve.
[6] The Asmari Formation was deposited at a time when the Tethys Ocean was finally closing and the Zagros Mountains were first rising.
[6] By the time of the succeeding Gachsaran Formation, this process had culminated in the sea shrinking to lagoons.
[1] The Asmari Formation is thickest in the northeastern part of the Dezful Embayment.
[1] The formation has various microfossils including planktonic foraminifera, echinoids, red algae, ostracoda, and oncoids.