FOURIER-SHAPE ANALYSIS OF SEDIMENTS FROM CORES FROM THE WEDDELL SEA

Fourier-shape analysis has been suggested as a useful technique for identifying depositional environments in glacial and marine settings. Five cores were collected during SHALLDRILL from the Weddell Sea. Twenty-one samples from these five cores were analyzed for grain shape. Samples were first treated with hydrogen peroxide and hydrochloric acid to remove organics and carbonates respectively. Quartz grains were then isolated from remaining feldspars and lithics using lithium polytungstates, a high density fluid. 200 quartz grains per sample were imaged and analyzed using a petrographic microscope and free imaging software. Through statistical analysis of Fourier coefficients several distinct “zones” or patterns have been recognized and correlate well with depositional environments independently identified. This study further illustrates the usefulness of grain-shape in distinguishing depositional environments in glacial-marine settings.