GEOLOGY AND ECONOMIC SIGNIFICANCE OF TERTIARY ROCKS, KHORWARI SECTION, SURJAN ANTICLINE, THANO BULA KHAN, SINDH.

Abstract

The Tertiary rocks ranging from Eocene (Laki Formation) to Pleistocene (Dada Conglomerate) in age are well exposed at the eastern flank of famous Surjan Anticline, district Jamshoro, Sindh, which in past remained focus for hydrocarbon exploration. In the present study, regional geology, including stratigraphy, structure, basinal division and tectonics of the studied area is discussed. While for the economic importance of the rocks both the flanks of the anticline were studied in detail. Stratigraphic studies were carried out on eastern flank. For achieving this target an ideal section at Khorwari Nala, from the core of anticline, was measured. The rocks are of mixed lithology of clastic and nonclastic, and shallow marine to non-marine origin. The clastic rocks are composed of shale, clay, sandstone and coarse grained sandstone while the nonclastic rocks are composed of limestone, dolomitic and arrenaceous-limestone. The possible lithological divisions on the basis of facies variations are also made. Two formations i.e. Gaj and Dada are already exposed around the Thano Bula Khan but are reported first time from the Khowari Section of the area. Preliminary hydrogeological studies were also conducted to ascertain surface and ground water conditions. Economic potential of minerals and rocks present in the area have also been discussed.