SUNDA SHELF

stable continental shelf, or platform, a southward extension of mainland Southeast Asia. Most of the platform is covered by shallow seas, including the southern South China Sea, the Gulf of Thailand, and the Java Sea, averaging less than 330 feet (100 m) in depth. Borneo and parts of Java, Sumatra, and associated islands are eroded metamorphic sections of the shelf left above sea level. The entire shelf, which has an area of 690,000 square miles (1,800,000 square km), was above sea level at one time, as is illustrated by the remaining traces of a stream network, the channels of which cross north over the shelf into the South China Sea Basin, and a second network going east into the Sunda Depression and the Flores Trough. The Sunda is separated from the Sahul Shelf (south) by the volcanic (and volcanically active) Lesser Sunda Islands and associated deeps. The existence of the shelf was first (1845) reported by G.W. Earl.