Submerged terraces in the Laccadive Islands, India

Abstract

The Laccadive atolls have recently been surveyed in detail (1:5,000 and 1:10,000). These surveys indicated the occurrence of a number of terraces on the seaward reefs of these islands at 7–12, 15, 21–36 (prominent) and 43–47 m depths. The first break in the profile of the seaward reefs occurs at depths of 3–5 m and on the windward side this extends down to about 12 m, the break at this shallow depth represents a wave-cut platform. The deeper terraces (>12 m) appear to have been formed during periods of lowered sea level. The most prominent terrace at 21–36 m is correlable with similar terraces recorded on other atolls. The terraces at Bangaram Island are covered by sediment while those at Kadmat do not have any sediment. In some of the atolls, surfaces at depths comparable to the seaward terraces are found in the lagoons also indicating extensive effects of lowered sea levels.