Plio-Pleistocene submarine glaciogenic morphology of the Chukchi Shelf, Arctic Ocean

Ongoing research aims to constrain the extent of grounded ice shelves around the Arctic Ocean during the last glacial periods. Here, the Chukchi region is of special interest because of its broad, shallow shelf. In general, little is known about possible sources and the areal extent of ice sheets if any existed on the Chukchi shelf.

Bathymetric and sub bottom profiler data from the Chukchi Sea margins as well as from the Arlis Plateau to the west show complex patterns of glaciogenic erosion like Mega Scale Glacial Lineations (MSGL) at water depths of more than 500 m. The different directions of those MSGL indicate the presence of ice shelves and streams and point to an East Siberian Ice Sheet of unknown size. On the Chukchi Shelf, no evidences for the existence of an ice shelf for water depths shallower than 350 m have been described yet.

We re-processed 2D multi-channel seismic data acquired in 2011 from R/V Marcus G. Langseth to investigate glaciogenic features on the shallow shelf. These data reveal new insights into the formation of the northern Chukchi Shelf. The first up to 500 ms TWT of the seismic data show strongly eroded reflectors and reworked sediments. Additionally, small-scale channels with a few tens of meters width and a depth of 20 ms TWT disrupt the horizons below the reworked layers. Furthermore, the seismic data show channels with widths up to few km and depths up to 150 ms TWT as well as truncated well stratified reflectors. All above described features can be observed on parts of the Chukchi shelf with water depths shallower than 900 m.