CT SCAN ANALYSIS OF PLEISTOCENE DEGLACIATION RECORDED IN ANTARCTIC SEDIMENT AT IODP SITE U1524

The Pleistocene has proven to be a crucial epoch of study due to its fluctuation between interglacial and glacial cycles. These fluctuations, observed through different glacial phases, can be interpreted through studying sediment shed off the Antarctic continent. Traditional descriptions of sediments and their depositional features, like laminae and dropstones, are limited by visual inspections of single surface views in a typical split core. Computerized scan tomography (CT) and image processing software are modern tools that allow for improved quantitative analysis of these features.

We compiled CT image processing and X-ray fluorescence (XRF) data to help better analyze phases of glacial cycling at International Ocean Discovery Program (IODP) site U1524. Site U1524 is located on the easter levee of the Hillary Canyon, north of the continental shelf edge of the Ross Sea in Antarctica. The Hillary Canyon is a channel for dense Antarctic bottom water and depositional sediment formed on the continental shelf.

The multiple slices of CT scans allowed us to characterize the size and abundance of dropstones more robustly than could be done from a visual core descriptions. Image processing allowed us to more quickly characterize subtle changes in lamination. When we combined our data with previously collected XRF elemental proxies such as ln Si:Al and ln Zr:Rb, a clear narrative of deglaciation emerged. This permitted the reconstruction of environmentally driven climatic changes and better constrained the timing of Pleistocene deglaciation at this location. Our research highlights how the use of emerging technologies such as CT scans and other image processing tools, especially in coalition with XRF element data, can help quantify sediment lithofacies analysis. Improved analysis will aid in better paleoclimate reconstruction and allow for more accurate modeling of environmental changes anticipated due to climate change.