Lower Dharamshala Fm

Jwalamukhi-B, Latitude: 31o 55'o2" N, Longitude: 76o 18' 58" E, Drilled depth: 6720 m. The top of the section is at 4420 m and the well terminated at 6720 m, with in Lower Dharamshala.

In the northwestern part of the Punjab Basin this formation is mainly argillaceous and contains thick sections of deep purple to chocolate colored shale siltstone with subordinate sandstone. In well Suruinsar-2 this section is composed of reddish brown, micaceous, calcareous siltstone and grey, fine grained, calcareous and occasionally micaceous sandstone. In Himachal Pradesh Lower Dharamshala is predominantly argillaceous with laterally impersistant sandstone. In the subsurface consists of reddish brown to chocolate brown, massive and occasionally calcareous shale and light grey to greenish grey, fine to very fine-grained non-calcareous sandstone. Heavy minerals are dominated by opaques. Among non-opaque ultrastable minerals rutile and tourmaline are predominant. The dominant clay minerals are Kaolinite and little found in Nurpur-1. Thickness: The thick of the Lower Dharamsala is around 1000 m in Jammu area measured in relatively undisturbed section (Ranga Rao, 1986). In Himachal Pradesh maximum thick is measured near Jwalamukhi area. In the subsurface. Maximum thickness penetrated was 2300 m in Jwalamukhi -B . 1303 m Jwalamukhi-2, 1164 m in Balt\h-1 and 1028 m in Suruinsar-2.

No diagnostic fossil of any significance. Magnetic polarity stratigraphy across Udhampur Syncline suggests an age of 19.9 Ma +/-1.2 Ma for the outcropping base of the coeval Upper Muree (Rao, Prasad, Bhalla, 1993).

The Dharamsala represents diachronous deposition on the feather edge of the foreland basin. Depositional environments comprised of semi-arid meander plain with sediment source from the rising but still distant proto-Himalayas to the north in which direction the Dharamshala foreland basin center was located.