Patala Fm
Type Locality and Naming
Makarwal Gr – upper formation. Holotype section: Patala Nallah, Western Salt Range. Author: L.M. Davies & E.S. Pinfold, 1937. Reference section: None.
Lithology and Thickness
Shallow-marine marl. In the type section it consists of shale and marl with subordinate limestone. The shale is dark greenish grey, selenite bearing, in places carbonaceous and calcareous, and contains marcasite nodules. The thin interbeds of limestone are white to light grey and nodular. Coal seams of economic value are present locally (Dandot area).
Thickness: 20-182 m. It is 27 m thick in the type section and 90 m at Khewra Gorge. The thickness varies between 30 m to 75 m in Surghar Range, 30 m to 80 m in Kohat area, 60 m to 182 m in Hazara area, and is 20 m thick in Kalachitta Range.
Relationships and Distribution
Lower contact
Conformably underlain by Lockhart Limestone Fm
Upper contact
Conformably overlain by Nammal Fm (transitional contact) in Salt Range, by Panoba Shale Fm in Kohat area and by the Margala Hill Limestone Fm in the Hazara and Kalachitta areas.
Regional extent
The formation is widely exposed in the Kohat-Margala Province (Ko-MP) (including Hazara area), Salt Range, and has been encountered in subsurface in oil wells drilled in Potwar and the T-CP.
GeoJSON
Fossils
The formation is richly fossiliferous. Larger forams include Actinosiphon tibetica, Assilina dandotica, Daviesina intermedia, Discocyclina ranikotenesis, Kathina nammalensis, etc. Smaller forams include Glandulina laevigata, Cincoriala cvouidea, Cycloloculina glabra, etc.
Age
Depositional setting
The sediments were deposited under transitional marine environments; higher proportion of carbonate facies in Kalachitta area points to stable marine setting while presence of coal in Salt Range indicate swampy conditions.
Additional Information
EMW: Coal, Source rock for oil & gas.