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Authors
Affiliations
1 Department of Geography, University of Pune, Pune - 41 1 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 70, No 3 (2007), Pagination: 459-473
Abstract
In this paper some observations have been made on the current paradigm of long-Distance paral1el retreat of great escarpments. The paper examines selected aspects of river and basin morphometry in the western Deccan Basalt Province (DBP) to get a better insight into the style and rate of Western Ghat evolution. Various drainage basin morphological attributes were extracted from digital elevation model (DEM) constructed by using the ca 90 m resolution Shuttle Radar Topographic Mission (SRTM) digital elevation data. The main findings that emerge from the analyses of the long profiles, basin shapes, length-area and slope-area relationships and escarpment sinuosity are (I) there is a remarkable similarity in the shapes of the long profiles of the principal coastal rivers suggesting that the headward erosion and growth of the drainage in the Ghat zone has proceeded, more or less, uniformly, and the geomorphic or geologic conditions have not favoured any particular river, (11) the coastal basins are more circular than expected, indicating that there is a tendency to increase the basin area laterally via tributaries, rather than longitudinally, and that the tributaries have also played a crucial role in the recession of the escarpment, (111) the Konkan rivers are characterized by severe deepening in the upper-medial portion and dominance of fluvial processes in the headwater reaches, and (IV) the Ghat Escarpment sinuosity is relatively low, but not very distinct from the sinuosity of the basin divides on the Maharashtra Plateau, implying that the geomorphic processes that create and sustain steep slopes along the western continental margin and over the Maharashtra Plateau are fundamentally same. All the geomorphic evrdences suggest that the tempo of Ghat Escarpment retreat is modest at best, and it seems that the Ghat scarp has receded maximum by a few kilometers.
Keywords
Western Ghat, Escarpment Evolution, Morphometry, SRTM-DEM, Parallel Retreat, Downwearing.