Marine sand resources in the south-west continental shelf of India

Abstract

Considering the impending shortage of construction material, the Marine and Coastal Surveys Division of the GSI, Mangalore has been in the look out for marine sand in the territorial waters and EEZ of the western offshore of India since the early nineteen nineties. Though sandy sediments were identified at many locations on the shelf and slope during several cruises, it was during two of the GSI’s cruises on board R.V. Samudra Shaudhikama, (SD-153¹ and SD-160² off Kollam, 1998-2000) that a detailed assessment of the distribution of construction sand was made. So far the GSI has executed five cruises exclusively for exploring construction sand off the West Coast. Out of these, two cruises off Kollam have indicated probable sand reserves of 184 million tonnes over an area of 180 sq km to a depth of 1.5 m down from the seafloor and located 25-40 km away from the coast. The data of the other cruises identified the occurrence of sand deposits off Kannur (267 million tonnes over an area of 500 sq km) and Chavakkad (1336 million tonnes over an area of 543 sq km). Off Kochi-Kollam marine sediments containing >85% silica sand have been identified during cruises SD-207³, 209⁴ and 216. Besides in an area, 8 km west of Beypore-Ponnani coast, good quality quartz sand was identified in two large basins close to the coastline where the thickness of sand formation exceeds 3.5 metres.