Topography and rainfall coupled landscape evolution of the passive margin of Sahyadri (Western Ghats), India

The passive margin of the Indian peninsula, revered as Sahyadri (Western Ghats) from time immortal, stretches along the western margin of the Indian Craton. It acts as an orographic barrier, and the frontal part of this continental-scale escarpment receives most of the rainfall, whereas the plateau top remains dry; this makes a case to study the processes of landform evolution in a climatically active and tectonically quiescent region. In our study, we demonstrated the modification of the Sahyadri with the annual forcing of the Indian Summer Monsoon (ISM). Seven major perennial river basins having higher drainage density and flowing on a lithologically varied terrain were studied using the SRTM 30 m data. The morphometric studies carried out in these basins, and the topographical analyses of the region offer the development of drainage systems on varied lithological terrain with diverse geological history. We demonstrated how the drainage basin erosion is moderated by the headward erosion by the streams as forced by the runoff water, probably by local base-level fluctuations and the forcing of ISM. The modification of the basin margin, i.e., drainage divide migration, is primarily affected by precipitation, whereas the lithological and structural factors have a second-order control on the overall retreat of the water divide.

Abstract licence: CC BY-NC-ND

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