A geologic and biostratigraphic framework for Miocene sediments near Khaur Village, northern Pakistan
A litho- and chronostratigraphic framework for approximately 3500 m of late Miocene sedimentary deposits with lateral exposure of 30-40 km is now well established for Siwalik deposits in the vicinity of Khaur Village, northern Pakistan. Based on paleomagnetic reversal stratigraphy and the constraints of long range faunal correlations, the time spanned is between 15-12 and 6 my BP. Boundaries of the major lithostratigraphic units are time-transgressive with respect to a paleomagnetic isochron traced laterally for 20-30 km. With reference to this datum, the zone of interfingering of the Dhok Pathan and Nagri Formations moves upward through approximately 1.5 my from east to west in the Khaur area. The major rock units represent adjacent alluvial deposits of two or more major fluvial systems with different characteristics of fossil preservation. Nearly 350 fossil-collecting localities can be placed in this litho- and chronostratigraphic framework. These localities span the entire 6-9 my interval, although the lower half of the section is only poorly fossiliferous. The sequence of faunas encompasses Pilgrim's Kamlial through Dhok Pathan faunal zones, but with this new chronostratigraphic framework it is now apparent that the classic faunal zones must be superseded by a biostratigraphic zonal scheme.