Deep Water Sand Body Formation by Contour Currents: Examples from Antarctica

RODRIGUEZ, ANTONIO, B. and JOHN B. ANDERSON, Rice University, Houston, TX

The Antarctic continental shelf averages 500 m deep. Rivers, deltas, and beaches have not existed there for millions of years, yet widespread sand bodies are located on the shelf, slope, and basin floor. They provide documentation of the capacity of ocean currents in forming sand bodies in a deep water setting. A large shelf sand body located on the North Victoria Land continental shelf in 300 to 700 m water is used to illustrate this mechanism of sand body formation.

Cores, grab samples, bottom photographs, sidescan sonar, seismic, and oceanographic data were collected from the area to understand the origin, character, and distribution of the sand body. Rice Bank is 1,250 km2 and is covered by more than one meter of gravels and medium to fine grained sands. The sands coarsen in an offshore (northeast) direction. Sands, sourced from volcanic (basalt) outcrops at Adare Peninsula, have been transported nearly 75 km along the shelf and upper slope by countour currents that impinge on the margin. Bank sands are also transported onshore by impinging currents.

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