Geomorphic assemblage of the Gulf of Kachchh coast,western India: Implications in understanding the pathways of coastal sediments

摘要

Coastal geomorphic landforms are the result of active offshore current dynamics in association with the available sediment influx. In the macrotidal regions like the Gulf of Kachchh, it is important to understand how is the coast responding to the sediment inputs and its accomodation. Details of the coastal geomorphology along the entire coast of Gulf of Kachchh have been recorded and constituent sediments analyzed for textural and compos-tional characteristics with standard methods. The study shows that the sandy segment between Jakhau and Mandvi has more terres-trial signatures in the form of composition of sediments which are getting reworked and redis-tributed therein by littoral drifts, onshore winds and cyclonic events. Whereas, the segment between Mandvi and Mundra represents a transition zone between the sandy coast to the west and muddy coast to the east. The segment between Mundra and Vadinar has wide mudflats which are acting as sink for most of the suspended sediment load which is largely derived from Indus river. The segment between Vadinar and Okha has narrow sandflat/mudflat with excep-tionally wide Okha Rann mudflats that are backed by rocky cliffs carved into the Tertiary rocks. The growth of coral islands offshore of this segment substiantiates the fact that most of the suspended sediments are deposited in the headward part of the Gulf of Kachchh.