Collaborative Research: Surveying and drilling the submerged reefs of the western Indian Ocean-applications to sea level history, monsoon history, and radiocarbon calibration

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Chris Charles and Rick Fairbanks Submerged fossil coral reefs are both a diagnostic measure of past sea level change and an unparalleled archive of tropical climate change. In many regions of the tropics, the submerged reef sequences were deposited throughout the major natural climate experiment of the last deglaciation. However, thus far, successful surveying and sampling of these reefs has only been achieved in a few locations. This award will equip a cruise to the Seychelles for the purpose of surveying and drilling submerged reefs in the western Indian Ocean that were likely deposited over the last 50,000 years. The objectives of the cruise activities are three-fold: (1) To understand the structure, age, and extent of fossil reefs--in essence, the response of the reefs to the known sea level variations of the last ice age cycle (2) To acquire coral samples that captured the state of the surface during times of greatly different forcing. (3) To acquire samples that allow paired radiocarbon and U/Th dating and that therefore might be used to calibrate the radiocarbon time scale. The operations, involving CHIRP seismic profiling and dredging, will be conducted off the eastern flank of the Seychelles Bank. This region features bathymetric (and other anecdotal) evidence for submerged reef terraces. The cruise will serve as an ideal platform for student training and will include two underrepresented minority students. This project is supported by the Marine Geology & Geophysics Program of the Ocean Sciences Division.