Laki Fm

Holotype section: Mari Nai, located southwest of Bara Nai. Author: F. Noetling, 1903. Reference section: None.

It is comprised mostly of hard, white, massive or nodular limestone. The formation consists mainly of cream colored to grey limestone that forms the cores of large anticlines in southern KrP; marl, calcareous shale, sandstone, and lateritic clay may become significant constituents of the formation locally and towards its base. The formation's chronostratigraphic equivalent, the Sui Main Limestone Fm has been discussed in detail, above.

Two basal members have been formalized by the SCP. A section exposed about 5 km SSW of Meting is designated as the type section of the above two members:

Sohnari Member: It consists of varicolored lateritic clay and shale with locally developed beds of yellow arenaceous pockets of limestone or ochre and lignite seams. Lenticular beds of variegated, ferruginous sandstone and white calcareous sandstone are common in the member. The member represents the basal part of Laki Fm and directly overlies the Ranikot Gr (Group).

Chat Member: It consists mainly of creamy white nodular limestone in the lower part and interbedded shale and limestone with subordinate sandstone in the upper part. The limestone is thin bedded and arenaceous where as the sandstone is commonly ferruginous. The shale is grey, greenish yellow weathering dark rusty brown, ferruginous and gypsiferous.

Thickness: 209-500 m. At the type locality, the formation is 240 m thick, and same at Bara Nai. It is 600 m at Tatti section in Kirthar fold belt, but absent in Marri-Bugti Hills. In the offshore, it seems to be increasing in thickness, but generally Ghazij shales and Laki limestone thickness is combined in offshore well reports. In the wells drilled to the east of Sulaiman and Kirthar provinces in PP and Badin area, respectively, the formation has been encountered, and ranges in thickness from 400-500 m.

Foraminifers: Assilina granulosa, A. pustulosa, Lockhartia hunti var. pustulosa, Flosculina globosa, Opertorbitolites douvillei, Fasciolites oblonga, Linderina brugesi, Dictyoconoides vredenburgi. Molluscs: Gisortia murchisoni, Velates perversus, Blagraveia sidensis . Echinoids: Amblypygus subrotundus, Echinolampas nummulitica . These fossils indicate an Early Eocene age.