Geomorphic fluvial markers reveal transient landscape evolution in tectonically quiescent southern Peninsular India

作者：Sanjay Kumar Mandal, Jean‐Pierre Burg, Negar Haghipour · 发表于：Geological Journal · 年份：2016 · DOI：10.1002/gj.2833 · 被引用次数：26 · 研究领域：Hydrology and Sediment Transport Processes、Geological formations and processes、Flood Risk Assessment and Management

The morphology of 19 adjacent westward‐flowing and four eastward‐flowing major catchments draining across the Western Ghat escarpment in southern Peninsular India was studied to examine how the channel patterns and their longitudinal profiles reflect the landscape evolution. Field surveys were complemented with the quantitative morphometric analysis of fluvial channel profiles using digital topographic data. Results show distinctive differences between eastward‐ and westward‐flowing drainage systems. The channel profiles of eight westward‐flowing drainage basins show an apparent morphological equilibrium characterized by concave upward shape, whereas most channels from the other westward‐flowing basins display knickpoint(s). All studied eastward‐flowing drainage basins display the morphological signature of disequilibrium in the form of knickpoints. The eastern and western margins of southern Peninsular India have experienced major tectonic events ~120 and ~65 Ma ago, respectively, and are since then tectonically quiescent. All studied westward‐flowing basins share the same Arabian Sea base level, flow over comparable lithologies and developed under similar climatic conditions. The studied eastward‐flowing basins have the Bay of Bengal as base level and similar climatic conditions. Therefore, the spatial variations in catchment morphometry is interpreted as a dynamic response to complex interactions and feedbacks between (i) pre‐existing topography along and across the escarp...