Datta Fm
Type Locality and Naming
Broach Gr - lowest formation: Holotype section: Datta Nallah, Surghar Range. Author: W. Danilchik, 1961. Reference section: None.
Lithology and Thickness
Sandstone. The formation is essentially sandstone of continental origin, very clean and mainly quartzose, fine to coarse grained, slightly carbonaceous and friable. Weathered surfaces show variable colors, mainly red, maroon, grey, green and white, because of which the name 'Variegated Stage' (Gee, 1945). Carbonaceous, laminated and sandy shales are also found intercalated with the sandstone; ferruginous glass sand and fireclay horizons are also present.
Thickness: 150-400 m. (In Hazara a maximum thickness of 10 m was encountered and in Kalachitta Range (KcR) it is only 6 m thick.). The thickness in the type locality is 212 m but increases to 230 m in Punnu Nallah to the west and over 400 m in the Shaikh Budin Hill. In the southwestern end of MR it reduces to 150 m. In the Salt Range, it is 150 m in Nammal Gorge (Western Salt Range), and decreases farther east till it is completely truncated due to the base Tertiary unconformity.
Relationships and Distribution
Lower contact
Unconformably underlain by Kingriali Fm (Late Triassic).
Upper contact
Conformably overlain by Shinawari Fm (gradational contact).
Regional extent
The formation is best developed in Trans Indus Range (TrIR) and Western Salt Range. It rests disconformably on the Kingriali Fm in the WSR, TrIR, Kalachitta Range and eastern Kohat. In Hazara the formation unconformably overlies doubtful Precambrian, Paleozoic and Triassic rocks. Excellent exposures of Datta Fm can be seen in Samana Range along the roadside.
GeoJSON
Fossils
No diagnostic fossils reported.
Age
Depositional setting
Mainly continental.
Additional Information
EMW: Glass sand and fireclay.