Baska Fm
Type Locality and Naming
Ghazij Gr – fourth formation in Sulaiman Province (SP). Holotype section: Near Baska village, ESR. Hypo: Dhurwali Chur, eastern Sulaiman Range (proposed by Siddiqui-written communication, as in Shah, 2009). Author: Hemphill and Kidwai, 1973. Reference section: None.
Lithology and Thickness
Claystone. In its type locality the formation consists of green shales and claystones containing alabaster in nodules and veins. The claystone alternates with bedded alabaster, gypsiferous limestone and marl. The alabaster beds range from 10 cm to more than 10 m. The claystone is light red and purple towards the base. In the Zindapir area, the formation consists of olive green shale, thinly laminated and fissile.
Thickness: 50-440 m. It ranges from 50 m near Jandola in the north to about 250 m in Zindapir, and 250-440 m in southern part of Sulaiman Range. In subsurface at Sui gasfield, it is 310 m thick.
Relationships and Distribution
Lower contact
Conformably underlain by Drug Fm
Upper contact
Conformably overlain by Habib Rahi Fm
Regional extent
The formation is widely exposed in the eastern Sulaiman Range, extending northward from Bugti area up to Waziristan. The gypsum beds observed in the type section may be traced southwards up to Bugti area and then northwestwards up to Spintangi in Harnai valley. Baska Fm. provides caprock for the gas trapped in Drug Fm. (Sui Upper limestone) in the Sui, Kandhkot gasfields.
GeoJSON
Fossils
Foraminifera: Cuneolina sp. Lockhartia hunti, Dictyoconoides vredenburg; Pelecypods: Bulsella sp., Babitia drougenis; Gastropods: Euspira cf. E. punjabenesis, Gosavia humberti.
Age
Depositional setting
Additional Information
EMW: Gypsum, and caprock for gas reservoired in Drug Fm. (Sui Upper limestone of oil companies) in Sui and Kandhkot gasfields.