Tropics

Abstract

The tropics is the geographical zone farthest from polar ice sheets, and has been little affected by glacioisostatic processes during the glacial cycles of the later Quaternary. Consequently, the sea-level history in the tropics is unique and reflects to a great extent the eustatic change of sea level. In the tropics, there are many proxy records suitable for reconstructing former sea-level positions. In particular, reef-building corals, mangrove peat, beachrock, and tubeworms are all good sea-level indicators and they have been widely used in the reconstruction of postglacial sea-level history. Despite the great wealth of sea-level data collected across the tropics, the best sets of sea-level data come from the region between the Australian and Asian continents, as well as the Caribbean. The sea-level data from the continental shelf of north Australia and the Sunda Shelf of southeast Asia, together with the sea-level data from the Strait of Malacca, are used to reconstruct a complete sea-level curve representative of the tropics for the past 20 kyr. It shows the position of the sea-level lowstand for the Last Glacial Maximum, phases of rapid rise of sea-level, and the mid-Holocene sea-level highstand. The sea-level curve not only reveals the eustatic sea level history, but also provides useful information about the characteristics of ice sheet melting, thus useful constraints to geophysical models.