Some geological processes in the macro-tidal regime of Gulf of Kachchh, northwest coast of India

Abstract

Echosounding and subbottom profiling, supplemented by side scan sonar profiling have been carried out followed by sediment sampling in the inner gulf of Kachchh. The results show the presence of sandwaves with a height of 3-6 m and wavelength of about 150-350 m in the Kandla Creek. The Sara, Sanu and Phang creeks exhibit uneven to rugged topography with about 4 to 12 m deep V-shaped channels. The seismic profiles across these creeks show 10-15 m thick clays. The channels are cutting across the reflectors. The axial part of the Hansthal Creek is uneven to rugged and is devoid of soft sediments, the flanks, however, show 2 to 8 m thick clays. The outer anchorage area in the south, by contrast, has smooth and even topography and stratified layers with maximum thickness of about 18 m. The acoustic basement is uneven but major channel cuttings are not noticed. Based on the results of the investigation it is concluded that the erosional processes are operating in the creeks while the outer anchorage area is undergoing the deposition. The area, has, perhaps, witnessed more frequent climatic fluctuations recently as evident from shallow seismic records.