Summary

The Parh Group, Moro Group, and Khadro Formation have been studied in the northern Kithar Range on the western side of the Sibi Embayment of Baluchistan Province, Pakistan. Biostratigraphic data assign Maastrichtian ages to the Parh and Moro groups and an early Paleocene age to the Khadro Formation. Five surfaces that record subaerial exposure and erosion of marine deposits and/or paleosol formation on marine deposits are recognized. These five surfaces, interpreted as sequence boundaries created by falls in relative sea level, have been correlated over approximately 3600 square kilometers.

Previous workers in the region (British Petroleum 1981, 1982; Hunting Survey 1961; Shah 1977, 1991) either reported the erosive surfaces as parallel unconformities with minor erosion or did not recognize them. None of the previous researchers recognized all five surfaces, nor did they recognize the extensive and variable erosion along the surfaces. Incised valleys are interpreted to be present along each of the four Maastrichtian-age surfaces. The early Paleocene surface is not believed to include incised valleys; instead a well-developed paleosol is present.

The origin of these erosive surfaces is ascribed to both tectonic and eustatic processes. Beck et al. (1996) presented evidence for Late Cretaceous initiation of the collision between the Indian and Afghan plates. Data from Baluchistan pertaining to these erosive surfaces support and strengthen their conclusion. In comparison, Haq et al. (1988) interpret only two “eustatic” falls during the Maastrichtian and early Paleocene.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah