Lockhart Limestone Fm

Makarwal Gr – middle formation. Holotype section: Lockhart Fort in the Samana Range. Author: L.M. Davies, 1930. Reference section: None.

Synonym: Lockhart Limestone, Lockhart Fm

Limestone. In the type area the limestone is cliff forming, it is grey to medium grey, medium to thick bedded, massive, rubbly and brecciated in places, the basal part is dark grey to bluish grey and flaggy. In the Salt Range and Trans Indus Range, the limestone is grey to dark grey, medium bedded, nodular with minor amount of calcareous shale in the lower part. In the Hazara and Kalachitta area, the limestone is dark grey and black in color. The limestone is generally bituminous and gives fetid odour on a fresh surface.

Thickness: 36-260 m. It is 60 m thick in the type locality, 36 m at Darsamand and 40 m at Thal in Kohat area. It is 70 m at Nammal Gorge in WSR, 260 m in Kalachitta and 90 to 242 m in Hazara area.

It is highly fossiliferous. The forams include Lockhartia conditi, L. conica, L. heimi, daviesins khatiyahi, Rotalia trochidiformis etc.

It was deposited under stable, broad shelf /ramp setting in most parts of Hazara, Kalachitta and Salt Range. However, in the type locality and Thal area it was deposited under slope conditions and was involved in the process of melange obduction during the last phase of collision between the Indian Plate and the Afghan Block.