Extensive debris flow deposits on the eastern Wilkes Land margin: a key to changing glacial regimes

Glacial sequences deposited on the base-of-slope and upper continental rise off the eastern Wilkes
Land margin show that depositional systems vary with time. During the early Oligocene to middle-late
Miocene times glacial sequences are dominated by extensive glacigenic debris flow deposits (GDFs) that
have lens or wedge shaped external geometries and internal chaotic seismic facies. Minimum runout
distances are between 15 and 50 km with lateral extent between 5 and 13 km. Thicknesses vary between 170
and 380 m. We suggest that large volumes of melt-water production by a dynamic East Antarctic Ice Sheet
(EAIS) define this glacial regime, which led to high sediment discharge onto the continental shelf and caused
extensive sediment failures on the continental slope and rise. In contrast, during the Late Miocene-Pliocene
transition there was an evolution to a more persistent cold-based EAIS characterized by decrease rates of
glacial erosion and decrease production of melt-water resulting in mixed turbidite and debris flow deposition.