Echosounding and sidescan sonar data from the western continental shelf between Vengurla and Vijaydurg have revealed the presence of submerged reef systems oriented nearly parallel to the shoreline at water depths of 60–100 m. Dredge samples collected from the pinnacles show evidence of shallow reef building corals. The reefs are in general up to 3 m high but at times have a low relief or are even buried in clay. The N-S extent of reefs was found to be of the order of about 8 km, implying that the pinnacles observed on the echograms are part of a larger reef system, now submerged. It is inferred that the reefs began forming and continued advancing shoreward as a result of a rise in sea level. The occurrence of reefs below the clay leads to the proposition that sudden climatic changes increased the runoff from the land causing the burial of the reefs after their formation during the mid-late Holocene.
Scleractinia (Hard Corals)
India - Western Continental Shelf