Coral microatolls preserve high-resolution data on past sea-level change, often to within a few centimetres. What’s more, precise ages of long-dead corals can be determined using radiometric dating techniques, allowing us to reconstruct a detailed history of such changes.
In this study, we aim to use data from coral microatolls to construct the first accurate and precise relative sea-level histories for anywhere on the Sunda Shelf in Southeast Asia. So far, we have developed or are developing sites on Belitung Island (northeast of Jakarta) and Mapur Island (southeast of Singapore), and we plan to start work in the Natuna Islands (northwest of Borneo) in late 2012. The record on Belitung extends from earlier than 7000 years before present (yr BP) to more recent than 5000 yr BP. Although samples from Mapur have not yet been dated, we anticipate the history recovered there will be younger.
Already, our record is noteworthy for the extent to which it contradicts the presently preferred models of sea-level change due to glacial melting. Sea-level change is not globally uniform and is relatively unexplored in the tropics as compared to temperate regions. The new data we have collected—and propose to collect in subsequent years—will provide much-needed context for understanding modern sea level change. Accurate estimates of sea-level change such as these will be needed to inform, calibrate, and validate the next generation of geophysical and climate models.