Pakistan Stratigraphy · stratigraphy.pk
Shogram Formation
https://stratigraphy.pk/formation/shogram-formation
Stratigraphic position
Band colour = period; texture = dominant rock type. Lines between bands mark the contact type. True scale makes height ∝ recorded thickness; hatched = thickness not recorded. Ages approximate, for ordering.
This unit (highlighted) within its province column; faded ends continue above and below. Line style marks the contact type.
The main Devonian limestone-and-quartzite unit of Chitral (about 800 m thick), rich in corals and brachiopods, now thrust over much younger Cretaceous rocks.
Named after Shogram village. Contains glaciomarine diamictites indicating Permo-Carboniferous glaciation on Asian plate.
Significance. The principal Devonian carbonate of the Chitral-Hindukush sequence, recording a marine-shelf environment; it is thrust south-eastward over the Cretaceous Reshun Formation along the Reshun Thrust and undergoes rapid lateral facies changes that have long complicated local correlation.
- Lithology
- Massive crinoidal dolomite in the lower part; bedded dolomite, fossiliferous limestone with corals and thin shale in the middle; and cross-bedded fine- to medium-grained quartzite with brachiopod-bearing limestone in the upper part.
- Thickness
- about 800 m
- Type locality
- Shogram village (mount), Yarkhun valley, Chitral
- Environment
- marine, shallow marine
- Introduced by
- Desio (1966)
Fossils
Provinces
References
- 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
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