Lithostratigraphy and vertebrate biostratigraphy of the early Miocene Himalayan Foreland, Zinda Pir Dome, Pakistan

Abstract

Deposits in the Sulaiman foothills and Zinda Pir Dome in west-central Pakistan provide new insight into the critical early Miocene record of Himalayan Foreland sedimentation and paleobiology. The Chitarwata Formation, which underlies the Vihowa Formation in the Sulaiman foothills predates the Siwalik deposits on the Potwar Plateau of north-central Pakistan and provides a record of mammals spanning the interval between the early Miocene Bugti fauna and middle Miocene to Pleistocene Siwalik faunas. Siwalik deposits on the Potwar Plateau are no older than middle Miocene; they represent fluvial environments. In contrast, the Chitarwata and Lower Vihowa Formations in the Zinda Pir Dome represent coastal-delta plain and fluvial environments, respectively. Biostratigraphic information from the Chitarwata Formation, coupled with paleomagnetic data (reported by Friedman et al., 1992) from coincident strata, suggest that coastal environments persisted in the area of the Sulaiman foothills until about 18.6 Ma when they were replaced by fluvial environments, probably representing the ancestral Indus River system. Apparently, during the early Miocene when sediments of the Chitarwata Formation were accumulating on the western portion of the Himalayan Foreland Basin much of the area of the Potwar Plateau to the north was being eroded. The overlying Vihowa Formation, along with the relatively contemporaneous Kamlial Formation on the Potwar Plateau, represent the appearance of widespread terrestrial sedimentation in the Himalayan Foreland Basin.