Sedimentary record of the last glaciation of the Bellingshausen Sea, West Antarctica

Massive, homogenous diamictons were deposited elsewhere on the margin during the last glacial period, when grounded ice masses advanced across the shelf. Sedimentological investigations using a multi-proxy approach and examination of the margin topography suggest that during this time a deformation till and subsequently a glaciomarine till were deposited on the shelf, while glaciogenic debris flows were deposited on the slope and rise.

The comparison of the clay mineral assemblages in the matrix of the diamictons with clay mineral assemblages of potential source areas reveals distinct pathways of grounded ice flow on the shelf. Lithogenic sandy muds overlying the diamictons were deposited by meltwater flows and/or marine currents on the shelf, and by turbidity currents and marine currents on the slope and rise, respectively. The sedimentation of the sandy muds denotes a deglaciation stage, when grounded ice started to retreat from the shelf, but semi-permanent sea-ice coverage still hampered biological productivity.