Tectonics of the western Himalayas
Overview of the geology and structure of the Salt Range, with observations on related areas of northern Pakistan
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Published:January 01, 1989
The Salt Range and its Trans-Indus extension bridges the reentrant between the outer ranges of the northwestern Himalaya and the Sulaiman Mountain arc. Upper Proterozoic to Recent successions occur in the range, which makes up the southern thrust front of the orogen.
There are two regional features of particular interest. The first is the occurrence of thick saliferous deposits of Eocambrian age, overlying Precambrian basement in the Potwar Plateau and thrust southward in the Salt Range over the alluvial Cenozoic. Thick, saliferous deposits also occur within the Eocene sequence of Kohat. These incompetent formations played a significant role in determining structure. The second feature is the presence of four major unconformities: between the marine Eocambrian to Cambrian sequence and the glacial, Lower Permian conglomerates, and below the Paleocene, the Miocene, and the late Pliocene–Pleistocene formations.
Metamorphic rocks, linking with the Precambrian crystalline basement of northwestern India, crop out only in the Kirana Hills some 80 km south of the Salt Range. Within the Salt Range and related areas, unmetamorphosed sedimentary rocks compose the exposed succession, mainly shallow-water marine, until mid-Tertiary time, and lacustrine and fluvial from Miocene time onward.
Prior to Quaternary time, only epeirogenic forces affected the region, accompanied occasionally by local warping. In contrast, during Quaternary time, the effects of the Himalayan orogeny extended southward. Accentuated by movement within the Eocambrian saliferous formation, the Salt Range developed as a complex anticlinorium, emplaced southward along a major thrust, which has recently been determined by seismic reflection measurements to involve a décollement of at least 20 km. Complex fold and fault structures resulted elsewhere within the region.
- Asia
- Cenozoic
- decollement
- evolution
- faults
- folds
- Himalayan Orogeny
- Himalayas
- Indian Peninsula
- maps
- marine environment
- orogeny
- Pakistan
- Potwar Plateau
- Punjab Pakistan
- Salt Range
- shallow-water environment
- Siwalik System
- structural geology
- tectonic maps
- tectonics
- thrust faults
- unconformities
- Surghar Range
- northern Pakistan
- Kohat
- Rawalpindi Group
- Bannu Plain
- Baroch Group
- Chharat Group
- Jhelum Group
- Khisor Range
- Makarwal Group
- Musa Khel Group
- Sakesar
- Salt Range Formation
- Soan Basin
- Sulaiman Mountain
- Surghar Group