The last several hundred thousand years have witnessed dramatic changes in sea level due to the growth and decay of the Greenland, Antarctic, and now-melted North American continental ice sheets. The last time sea level exceeded modern day levels was 120,000 years ago, at which time it was as much as 6-8 m above present. Given that 10% of the world’s population lives in low lying coastal regions, understanding the causes, mechanisms, and rates of past sea level changes are of critical importance.
Several methods have been developed for reconstructing past sea levels including analysis of the oxygen isotopes of foraminifera, which take in oxygen isotopes. Radiometric dating of select species of coral, and of submerged flowstones, stalagmites, and stalactites allow us to correlate a date with the already determined timing of subaerial exposures.
One limitation to sea level studies involves tectonic activity which raises the land surface, thus altering the evidence of past sea levels. If the tectonic activity is not corrected for, then an incorrect sea level height will be obtained. Therefore, one area often studied is The Bahamas Bank, an area that is tectonically stable and that can thus record sea level without the complications of tectonic uplift.
This project involves a synthesis and summary of sea level reconstructions from The Bahamas over the last 120,000 years, with the goal of understanding the large scale impact on the world population of sea level rising above its current day position due to global climate change and the resulting melting of the continental ice sheets in Greenland and Antarctica.
Daniel Pawlak, ’13
Sponsor: Rhawn Denniston