DETERMINING MIDDLE MIOCENE THROUGH PLIOCENE CHANGES IN BASAL ICE CONDITIONS THROUGH SEDIMENTOLOGICAL ANALYSES OF DIAMICTITES IN AND-2A CORE, ROSS SEA, ANTARCTICA

During the Mid-Miocene through the Early Pliocene, the East Antarctic ice sheet went through a period of sheet expansion and contraction. Previous studies have suggested that the ice-sheet changed from a wet-based temperate ice sheet to a dry-based polar ice-sheet at ca. 14 Ma. Utilizing a sediment core obtained through the Antarctic Geological Drilling (ANDRILL) program, conditions in the basal ice will be monitored. Glaciers eroded bedrock from the Transantarctic Mountains and deposited sediments into the embayment mixing with materials transported from further south. The basal melt out deposited diamictites, ranging from coarse angular fragments to well-rounded, sedimentary clastic fragments that are supported by a fine-grained matrix. By studying this matrix, both the mineralogy and chemistry can be determined and used to obtain the provenance of the materials. Through particle size analysis, the transportation of glacial sediments will be traced as well as providing an example of the conditions of the original depositional environment.