Late Quaternary sedimentation history of the Himalaya and its foreland

Abstract

Himalaya and its foreland acted as a coupled system that responded to the climate variability and evolved as a thrust and fold belt. The river systems draining the Himalaya, the Ganga foreland act as an artery that helps registering climate and tectonic signals into its geomorphology and sedimentary history. The paper discusses the late Quaternary landscape evolution of the mountain and its foreland and reviews the published literature in the context. It mainly focusses on the alluvial landscape and compiles the chronological data to decipher the evolution of mountain, the Ganga foreland and the delta. The review suggests that rivers in Himalaya largely aggraded during the climatic transition between the dry glacial and wet interglacial. The incision of the river valleys took place during peak of the warm interglacial periods when Indian Summer Monsoon strengthened. The Ganga plain rivers exhibit varied geomorphology that depended on the proximity to the mountain, forebulge of the foreland and type of drainage (transverse or axial). The rivers in the west are incised while those in the east are shallow and avulsive. The sedimentary history of the Ganga plain implies being forced from N-S movement of monsoon front and foreland dynamics over the past 120 ka. The delta region of Ganga has been responding to the fluctuating sea level and delta progradation (retro-gradation).

Late Holocene river dynamics and sedimentation in the Lower Ganga plains, India

“…The Rarh plains (RP) form mostly the western part of LGP (Bagchi & Mukherjee, 1979; Bandyopadhyay et al, 2015; Biswas, 1987; Chaudhuri, 1985; Kumar et al, 2020), which is located more than ~200 km upstream of the modern‐day tidal limit (Figure 1). The area is mainly contributed by the western tributaries of the Bhagirathi‐Hooghly River system (a distributary of the Ganga River system) and has long been considered the oldest part of the Ganga‐Brahmaputra delta (GBD) (Bagchi, 1944; Basu, 1973; Niyogi, 1975).…”

Flood Susceptibility Assessment Using Geospatial Multi-Criteria Framework: A Study in Lower Mahananda Basin, India

“…The Gangetic rivers experience high ood discharges and temporal variability where bulk of the rainfall happens between June to September. The rivers on the western portion of Ganga plain are incised in nature whereas the eastern rivers are shallow (Kumar et al, 2020). Therefore, the annual oods in the Ganga-Brahmaputra plain are morphologically more signi cant rather than the occasional large oods due to the channel abandonment, avulsion, bank erosion etc.…”