Tectonic geomorphology of the Mahi river basin, western India

Neotectonic activity along pre-quaternary tectonic trends has played a major role in the evolution of Mahi drainage basin. The Mahi basin is controlled by NE-SW and WNW-ESE Aravalli trend in the uplands and by NNW-SSE Tertiary basement faults in the distal part. Lineament analysis shows three structural trends in the area which are related to major regional tectonic trends. Stream orientations indicate that the NNE-SSW and NNW-SSE trends represent lineaments which were active during the youngest tectonic phase. The NE-SW and WNW-ESE trends are slightly older. The evolution of overall configuration of the basin is attributable to neotectonic activity along WNW-ESE and NE-SW trends which have been modified by a later phase of tectonic activity along NNW-SSE trend. Morphotectonic analysis has been helpful in assessing the relative degree of tectonic activity in the different geomorphic zones of the Mahi river basin. An increasing degree of tectonic activity towards the NE conforming to the northeastward extension of the Aravalli range where the central axis of the range lies, has been indicated.