About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

Journal of Sedimentary Research (SEPM)

Abstract


Journal of Sedimentary Petrology
Vol. 28 (1958)No. 3. (September), Pages 274-285

Distribution of Calcium Carbonate in the Shelf Sediments Off East Coast of India

M. Subba Rao

ABSTRACT

Distribution of calcium carbonate in the sediments of the continental shelf off east coast of India from Ganges to Madras has been studied with reference to the distance from the coast, configuration of the shelf, and the silt-clay component of the sediments. The shelf is covered to a very large extent by terrigenous muds. Only on the outer shelf off Madras and Kakinada-Santapilli coast, do the sediments contain more than 50 percent calcium carbonate, and these are classified as carbonate sediments. The carbonate sediments are coarse in nature and exhibit their maximum spread off Visakhapatnam where the calcium carbonate increases from 5 percent near shore to 75-80 percent at 60 fathoms depth. Beyond the continental shelf it decreases to about 10 percent. On the basis of carbonate and silt-clay contents of the sediments in relation to the shelf topography and hydrodynamical conditions, the shelf, particularly off Visakhapatnam, is divided into three zones: (1) zone of active deposition of terrigenous material extending from coast to 331/2 fathoms, (2) zone of moderate deposition of terrigenous material existing between 331/2 and 521/2 fathoms, and (3) zone of slow or non-deposition outward of 521/2 fathoms depth. The sediments in the zone of slow deposition which is also the calcareous sediments zone, are believed to have been laid down when the sea level was relatively lower than now an to have not yet been covered by the present day deposition of terrigenous material.


Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24