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Depositional environment of the Bagh-e-Vang Formation – the only occurrence of upper Lower Permian in Iran

Yegane Bizhan Yousefi, Van Loon A.J. (Tom), Fard Sakine Arefi, Farahpour Mohammad Mehdi, Sharahi Safoora Yasbolaghi

Geologos

2021

Vol. 27, No. 1

1--14

A transgression of the Tethys Ocean occurred in east central Iran, like in other areas of the Tethys Ocean, around the Yakhtashian/Bolorian (regional chronostratigraphical units corresponding with the Artinskian/Kungurian of the Early Permian) transition. This led to the development of a carbonate platform that is represented in the Shirgesht area on the northern part of the Tabas Block by the Bagh-e-Vang Formation, which constitutes the only known sedimentary unit from the late Early Permian in Iran. Field data and thin-section analysis indicate deposition on a carbonate ramp with barriers separating a lagoonal area with intertidal mud flats from the open-marine environment. The overall transgres-sive development is indicated by the presence of open-marine sediments on top of the barrier and lagoonal sediments.

Przebieg sedymentacji osadów „sarmatu detrytycznego” na obszarze pomiędzy Stawianami a Sędziejowicami

Brzozowska J.

Przegląd Geologiczny

2004

Vol. 52, nr 1

55-60

Studies undertaken by the author in the area between Stawiany and Sędziejowice shown that deposits known as “detrital Sarmatian” created barrier facies, thus confirming arguments of Czapowski (1984). These deposits are indicated in the landscape morphology as elongated and sinuous banks which during the early Sarmatian became the barriers built by along-shore currents of SE–NW direction. Analysis of the paleotransport directions showed diversification of the local transport, NW-directed in the south-east part of the area and S and SE-directed in its northern part. This suggests that besides the a long-shore current, which in the early Sarmatian built the “barrier” that separated the Chmielnik Bay to the E from the Korytnica Bay to the NW, there were also some different directions of clastic material supply. Within Sarmatian deposits two lithofacies were distinguished, with different lithification stage, material sorting and lamination type. Both facies are separated by an erosional boundary. One of these facies represents sediment that built the barrier, the other one consists of sediments deposited in the shallow, coastal environment. Discussed deposits a transgressively overlap the older deposits; in the northern part of the area they lie on the Kraków Clays and in the southern part they lie on the gypsum of the Krzyżanowice Formation. Main carbonate components are algae of genus Archaeolithothamnium, foraminifera and crumbled molluscs shells. The most common fossil is a bivalve Mytilaster (Upper Badenian–Lower Sarmatian).