Micromorphology to Understand Landscape Evolutions and Pedogenic Response to Neotectonics and Holocene Climatic Changes: A Case from Soils of the Ganga Basin

The Ganga Basin (GB) is one of the largest fluvial sedimentary basins in the world. Because of its unique position in front of the active Himalayas in the north and the Indian craton in the south, the basin is tectonically active. The surficial part of this vast basin is covered with modern soils ~1–2 m depth. The GB is remarkably flat with a gradient of <0.02% from west to east over a transect of about 2000 km and is referred to as the Indo-Gangetic Plains (IGP). The research work carried out over the last four decades on soils and landforms of the IGP has shown that micromorphology is potentially useful for soil-geomorphic investigation and to determining the interrelationship of the pedogenesis, landscape evolution, and climate change during the Holocene. Micromorphology of the IGP soils has been utilized to identify and establish five geomorphic surfaces (QIG1 to QIG5) with varying degrees of soil development over the entire IGP. The IGP soils are defined by polygenetic features in the older geomorphic surfaces (>2.5 ka) with a distinct record of climatic changes and neotectonics. This chapter describes the application of micromorphology to investigate the pedogenic response to neotectonics, landscape evolution, and climatic changes over the last 13.5 ka in soils of the IGP.