Late quaternary evolution and morphostratigraphic development of the ganga plains

Abstract

Climate and tectonics have played a fundamental role in the morphostratigraphic development of various mega-geomorphic features of the Ganga Plains. In the past few decades, research was focused on the assessment of the relative importance of various forcing factors that governed sediment accumulation patterns in time and space in the Ganga Plains, which when considered together explain the geomorphic diversity within the basin. The Ganga basin is broadly divided into the Eastern Ganga Plains (EGP) and the Western Ganga Plains (WGP) based on the rate of subsidence, stream power and sediment yield of rivers. The EGP is dominated by the megafans, while the WGP comprises of incised valleys and the intervening interfluves. The climatic forcing like the Indian summer monsoon has played an important role in the development of incised valleys during the Marine Isotope Stage 2 following the Last Glacial Maximum. The tectonic processes, besides exercising broad regional-scale controls, have affected the formation of alluvial fans and piedmonts in closer proximity to the faults. An integration of these factors along with few chronostratigraphic records of cliff sections and drill cores and the subsurface data of the hydrocarbon industry have helped in building a stratigraphic framework of the Late Quaternary sequences within the Ganga basin.