Microfossil Assemblage from Dhok Pathan Formation (Middle Siwaliks) exposed near Polian Prohita, Una District, Himachal Pradesh, India

Abstract

The Fluvial molassic sediments of Middle Siwalik which is considered to be deposited within the time range from 10.1-5.1 Ma holds a long record of the provenance and palaeoenvironmental history of Siwalik foreland basin. A mudstone bed of Dhok Pathan Formation exposed near Polian Prohita, Una district, Himachal Pradesh has yielded a diverse fossil assemblage. The present assemblage include mollusks Parreysia sp., Lamillidens sp., Melanoides sp. and Gyraulus sp. The charophytes include Chara globularis globularis, Chara globularis aspera, Chara sp. indet, Lychnothamus breviovatus and Lamprothamnium papulosum. Ostracodes Stenocypris sp. and Candona sp. have also been reported here. Fish teeth of certain morphotypes belonging to the Channidae and Cyprinidae families were also recorded. The majority of the fossil assemblage suggested that a warm tropical to subtropical humid climatic condition was prevailing during the deposition of these sediments. As this fossil assemblage is found restricted to a particular mudstone bed it can be inferred that there existed a localized swampy to overbank pond environment in within the braided river system deposits of Dhok Pathan Formation.