Wulagai Fm
Type Locality and Naming
Khanozai Gr – upper formation: Holotype section: Tarkai-Gwal section, Axial Belt. 60 km NE of Quetta. Author: M. D.Williams, 1959 - name adopted by M. Anwar et al. (1993). Reference section: None.
Synonym: Wulgai Fm
Lithology and Thickness
Pelagic marl. The formation consists of indurated dark grey mudstone and shale with intercalations of thin limestone, calcareous mudstone and sandstone. The shale in the lower part is dark grey to black in color, and the thin limestone beds in the upper part are crystalline and exhibit black, dark grey or greenish-grey color. The shale is purple, olive, brownish grey to greenish grey and well bedded.
Thickness: 180 m. At the type section, the formation is 180 m thick. At other places like Wulgai section, the formation is tectonized and disturbed and attains a thickness of 1,180 m (Williams, 1959), whereas according to Sokolov & Shah (1965) the total thickness is 985 m.
Relationships and Distribution
Lower contact
Conformably underlain by Permian beds in Shirinab section, disconformably in Ghazaband section but tectonically disturbed in the Wulgai section. Its lower contact with Gwai Fm is sharp where a fossiliferous gritty limestone with limestone boulders is present; this bed contains spiriferinids and crinoidal debris. According to authors, its age is Middle Triassic and indicates a disconformity.
Upper contact
Conformably overlain by Jurassic sequence (transitional).
Regional extent
This formation is exposed only in the Axial Belt, which is the ophiolite-and-thrust belt in Zhob, Kallat and Khuzdar regions. Wulagai Fm shows close similarity with the Triassic rocks of the Mount Everest region (Wager, 1939).
GeoJSON
Fossils
The formation is sparsely fossiliferous. Columbites sp., has been reported from its lower part whereas Halorites sp., Jovites sp., Pararcestes sp., Arietoceltites sp., Halobia sp., and Monotis salinaria have been obtained from the upper part. According to Fatmi (1977), these fossils indicate an Early to Late Triassic age.
Age
Depositional setting
Similar to the underlying Gwai Fm, it is composed of clastic and carbonates turbidites of deep-water origin and is found in thrust sheets.
Additional Information