Kirthar Fm
Type Locality and Naming
Holotype section: Gaj River section. Hypo: Spintangi Gorge, east of Quetta. Author: W.T. Blanford, 1879. Reference section: Lithology same as in the type section but with a much reduced thickness.
Lithology and Thickness
It is predominantly a limestone with some shale and marl. The limestone is light grey, cream colored or chalky white, and weathers in grey, brown or cream colors. It is thick bedded to massive, in places nodular, and occasionally contains algal and coralline structures. The shale is olive, orange yellow, grey, calcareous, soft and earthy. In some localities, the upper half of the unit is exclusively cliff forming massive limestone (Gorag member of HSC, 1960).
Thickness: 300-1,270 m (reduces to 15-30 m on the western side of Kirthar Range). In the type locality it is 1,270 m thick, 15-30 m in the western Kirthar Range, 300 m at the principal reference section.
Relationships and Distribution
Lower contact
Conformably underlain by Laki Fm. In Axial Belt it is underlain by different Early Tertiary, Mesozoic and possibly Paleozoic rocks where the contact is marked by a thin lateritic or pebbly conglomeratic bed in certain areas.
Upper contact
Unconformably overlain by Nari Fm (Oligocene) in KrP.
Regional extent
It is restricted to Kirthar Province but is widely distributed in the region, and parts of the adjoining Calcareous Zone of the Axial Belt.
GeoJSON
Fossils
Forams: Actinocyclina alticostata, Assilina cancellata, A. rota, A. irregularis, Nummulites beaumonti, N. gizehensis, Dictyoconoides cooki etc.
Age
Depositional setting
Additional Information