Sedimentary facies analysis of the fluvial environment in the Siwalik Group of eastern Nepal: deciphering its relation to contemporary Himalayan tectonics, climate and sea-level change

Abstract The Siwalik Group, ranging from the Early Miocene to Pleistocene, is believed be deposited in fluvial environment and controlled by contemporary Himalayan tectonics climate. In this study, we established its controlling factors responsible for deposition of succession along Muksar Khola section eastern Nepal Himalaya. Five sedimentary facies associations are identified; these interpreted as deposits flood plain-dominated fine-grained meandering river (FA1), flood-dominated overbank (FA2), sandy (FA3), anastomosing (FA4), debris flow-dominated gravelly braided (FA5). These changes system occurred around 10.5 Ma, 10.0 5.9 Ma 3.5 defined existing magnetostratigraphy constraints, due effects hinterland tectonics, climate sea-level change continuous drifting foreland basin towards concerning depositional age. thick an intraformational conglomerate reveals intensification monsoon started present study also shows asynchronous exhumation Himalaya east west brought a significant difference Neogene basin.