Bahadur Khel Salt Fm
Type Locality and Naming
Charrat Gr – third formation in Kohat-Margala Province (Ko-MP). Holotype section: Bahadur Khel Salt quarry. Author: C. R. Meissner et al., 1969. Reference section: None.
Synonym: Bahadur Khel Salt, Bahadur Khel Fm
Lithology and Thickness
Evaporite. The salt is white, and bedded to massive, and at places it contains black stringers. It is not reddish like the Precambrian salt of Salt Range Formation. Except where the salt is very massive and crystalline, its stratification is generally well marked. The salt is impregnated with sulphate of lime (gypsum) but not with potassium and magnesium as in the Salt Range. Clean Bahadur Khel salt composition mentioned in GSI Mem. 11, 1875 gives 59.2% Cl., 1.50% SO2, 1.06% CaO, 37.47% Na, and insoluble content 0.45% ( as in Kazmi & Abbasi, 2008). The salt grades laterally into the Panoba shale.
Thickness: 100 m (estimated). Thickness of salt is difficult to measure due to its diapiric nature. At Bahadur Khel quarry a thickness of 480 m was drilled, but does not represent the true thickness. Its thickness, however, is estimated to be about 100 m.
Relationships and Distribution
Lower contact
Conformably underlain by Panoba Shale Fm at places.
Upper contact
Conformably overlain by Jatta Gypsum Fm
Regional extent
It is restricted to western Kohat-Margala Province (Ko-MP) (west of Indus River), where the Bahadur Khel Salt Fm and the overlying Jatta Gypsum Fm is exposed in the cores of tight anticlines along a narrow belt. The rock salt, near Bahadur Khel outcrops over a length of 12 km with a width of about half a kilometer.
GeoJSON
Fossils
Well preserved fossil leaves, probably of dicotyledonous type have been noted by Gee, 1945 (as in Shah, 2008) in certain bands of clay and sandstone interstratified with grey salt.
Age
Depositional setting
The salt was deposited in shallow sea, most likely in restricted small basin(s), which were probably local shoals of early Eocene regression. These basins were recharged with saline seawater either through inlets or by overtopping the barrier during storm (Tanoli et al., 1993 as in Shah, 2009). Wells, 1984 (as in Shah, 2009) has suggested deep-water origin.
Additional Information
EMW: Salt.