Sewakht formation

This unit (highlighted) within its province column; faded ends continue above and below. Line style marks the contact type.

A Late Devonian greenschist-and-limestone unit correlated with the Shogram Formation, southwest of Shogram.

Sewakht formation is named by Leake et al. (1989) for greenschist limestomes, dolomitis carbonate and sandstone may correlate with westen continuation of Owir formation. Owir formation is is named after Owir An and named by Shah (2009) following the Sedimentary series of Owir by Hayden (1915). It consists of shale with conglomerate and limestone. This formation consists of fossil Receptaculites neptuni (Difrance). It is first collected in Iran by Flugel (1961) and second time from Chitral collected by Diemberger and described by Vogelanz (1969). According to fossil collecter Diemberger, it was collected from the western end of series which covers the Tirich Mir (granite) Pluton with vertical dipping. It is correlated with Sewakht formation. Conaghan (in Talent et al. 1981) collected blocks of red oolitic limestone with Receptaculites from Ojehor Gol about 1km above its confluence with Lutkhu rive. Since Vogelanz's loca;ity is within Ojehor Gol watershed. The blocks have also yielded diverse conodonts. The age is determined as Late Devonian. Wakhan slates are named by Hayden (1915) for black slate, siltite and sandstone containing fossils of Permian to Triassic age. It forms a continuous belt from Tirich Mir in the west to the Chapursan valley in upper Hunza in the east. From south (Arkari) to north the metamorphism is being decreased and represented by Wakhan slates instead of

Significance. A Late Devonian unit exposed south-west of Shogram, above the Reshun Thrust and in the same tectonostratigraphic position as the Shogram Formation, with which it is correlated; the related Owir Formation yields the alga Receptaculites neptuni.

Provinces

• Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
• Kazmi, A.H. & Jan, M.Q. (1997). Geology and Tectonics of Pakistan. Graphic Publishers, Karachi.

Reviewer confidence: medium