Overview | Earthquake | Drought | Fire | Flood & Cyclones | Landslide & Soil Erosion | Volcano
Structure and tectonics of Kachchh region of western India: An appraisal
Geomorphologically, Kachchh can be categorized into four major E-W trending zones (Fig. 2):
 Fig 2 Geomorphic Map of Kachchh The Kachchh region abounds in evidences of continued tectonism since Mesozoic times and its physiography is a clear manifestation of active tectonism. It provides a good example of a terrain where neotectonic activity has influenced evolution of landforms and fluvial regime. Obviously, the changes are represented by (1) periodic reactivation of movements along the older faults, (2) development of new fractures (faults, joints) (3) development of related fault propagation folding during uplifts along fault blocks and (4) modification of older drainage and development of new fractured controlled streams. Various major stream trends, events of terracing and channel entrenchment, all point to the response towards reactivation along the fault planes. The stream courses not only follow tectonic trends (faults and joints) but their valleys have preserved good evidences of flexure related uplifts also. Streams of varying dimensions belonging to several generations exhibit lineament control and the channel trends and their morphology provide valuable information on nature and sequence of tectonic events of the Quaternary period. Occurrence of paired strath and fluvial terraces along the various river valleys, incised channels and recent gullies along the margins of the Banni Plains-Great Rann reveal close relationship between the drainage development and active tectonic movements. These are envisaged to have taken place during Quaternary period and continuing even upto the present [(Biswas, 1974; Kar, 1993b; Malik et al. 1999; Sohoni et al. 1999; Malik et al. (In press)]. Geomorphology The variety of the geomorphic facets of the Kachchh peninsula such as the present surface configuration, its landforms, the drainage characteristics and the relief pattern reveal a complex interplay of tectonism, sea level changes, lithology and the Cenozoic processes of erosion and deposition. Interestingly, within the limits of the Kachchh peninsula, one comes across conspicuously high hills and extensive low plains. The uplands comprise rugged hilly terrains exposing folded Mesozoic rocks (Middle Jurassic-Lower Cretaceous) bordered by thin strips of gently dipping Cenozoic rocks (Paleocene to Pleistocene) which form the coastal plains. The highlands are the areas of uplift whereas the plains of low lands represent structural basins between the uplifts and are made up of alluvium, mud and salt flats (Ranns). Topographically, the Kachchh region is made up of east-west trending hill ranges i.e. the Island belt, the Kachchh Mainland and the Wagad. The hill ranges in each of these areas are separated by large tracts of low ground. All hill ranges and the intervening low ground run almost parallel, a characteristic feature indicating that the topography has been controlled to a large extent by the geological factors of folding, faulting and lithology. The highest peak in Kachchh is that of Kaladungar (D 465 m) in the Pachcham island. On the Kachchh Mainland there are several peaks, the Nanadungar showing the maximum altitude of 430 m. The landscape comprises rocky highlands standing out like "islands" amidst the vast plains of the Great and Little Ranns of Kachchh. Whereas the Ranns and Banni are the depositional plains of Recent times, the highland areas bear evidences of multiple erosional cycles Biswas (1987). According to Biswas (1974) the five denudational cycles are correlatable with major periods of tectonic movements in the region. |