Riiser-Larsen Sea

[5] The bedrock in the Riiser-Larsen Sea is one of the oldest around Antarctica (145 Ma) and erosion over this long timespan has produced the largest submarine canyons of the continent.

The continental shelf of the Riiser-Larsen Sea is relatively narrow and forms rugged terraces at a depth of 750 m (2,460 ft), probably the maximum extent of seafloor-reaching icebergs.

The buried canyons formed during a period of maximum glaciation when grounded icebergs reached the shelf edge which resulted in a peak in sediment transport.

[6] The Riiser-Larsen Sea was one of the first Antarctic marginal basins to be affected by the expanding ice sheet at c. 34 Ma.

The expanding ice sheet initially triggered slumps and flows of debris that were deposited on the upper continental rise.

Then large channel-levee complexes developed on the upper rise resulting in an unconformity associated with the Middle Miocene intensification of the Antarctic Circumpolar Current.