Sediment Volume Record of Paleogene-Neogene Transantarctic Mountains Erosion and Landscape Modification, McMurdo Sound Region, Antarctica

The interplay of tectonics and climate is recorded in the sedimentary strata within Victoria Land Basin, McMurdo Sound, Antarctica. Patterns of Cenozoic sedimentation are documented from interpretation of seismic reflection profiles calibrated by drillhole data in McMurdo Sound, and these patterns provide enhanced constraints on the evolution of the coupled Transantarctic Mountains-West Antarctic Rift System and on ice sheet advance/retreat through multiple climate cycles. The research focuses on shifts from warm based to cold based ice sheets through the variable climate and ice sheet conditions that characterized the early to middle Miocene. The study seeks to test the view that cold based ice sheets in arid, polar deserts minimally erode the landscape by calculating sediment volumes for critical climatic intervals. Revised seismic mapping through McMurdo Sound has been completed, utilizing the seismic stratigraphic framework first established by Fielding et al. (2006) and new reflectors marking unconformities identified from the AND-2A core (Levy et al., 2016). Reflector age constraints are derived by tying surfaces to the Cape Roberts Project, CIROS-1, and AND-2A drillholes. Seismic facies coupled with AND-2A core provenance information provides insight into depositional mechanisms and ice sheet behavior. Seismic facies transitions occur across the major unconformity surfaces in the AND-2A core. Sediment volume calculations for subareas within McMurdo Sound where reflectors are most continuous indicate substantial decreases in preserved sediment volume between the Oligocene and Early Miocene sequences, and between the early and mid-Miocene sequences. Sediment volumes, used in combination with an ice sheet model in a backstacking procedure, provide constraints on landscape modification and further understanding of how landscapes erode under warm and cold based ice sheet regimes.