Diatoms and Cosmogenic Isotopes as Tracers of West Antarctic Ice Sheet History and Processes

Northern Illinois University, Dekalb IL

Investigators

Abstract

9980364 Scherer This award provides support for three years for analysis of sediments from beneath current and past grounded ice of the West Antarctic ice sheet. Diatoms and 10Be will be used not only for evidence of past deglacial conditions, but also as sedimentary tracers of microstratigraphic variability in piston cores recovered by Caltech glaciologists from beneath ice streams B, C and D, and inter-stream ridges. Similar analyses will be performed on sediment cores recovered from beneath the southern Ross Ice Shelf, and the southern Ross Sea near the ice front. Diatoms make excellent sedimentary tracers because, unlike most sedimentary particles, they have known initial conditions (original size, shape, approximate age, and environment of origin). The current study includes quantitative analysis of comminution of Ross Sea diatoms, from laboratory studies, using the ring-shear device developed by Iverson et al. (1998). Preliminary analyses suggest distinctive patterns of diatom breakage that could lead to guidelines for estimating load and shearing of marine diamictons, which may have important implications for interpreting past ice sheet configurations.