Glacial morphology and post-glacial contourites in northern Prince Gustav Channel (NW Weddell Sea,Antarctica) |
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Authors: | Camerlenghi Angelo Domack Eugene Rebesco Michele Gilbert Robert Ishman Scott Leventer Amy Brachfeld Stefanie Drake Allison |
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Institution: | (1) Istituto Nazionale di Oceanografia e di Geofisica Sperimentale – OGS, Trieste, Italy;(2) Geology Department, Hamilton College, Clinton, NY, USA;(3) Department of Geography, Queen's University, Kingston, ON, Canada;(4) Department of Geology, Southern Illinois University, Carbondale, IL, USA;(5) Department of Geology, Colgate University, Hamilton, NY, USA;(6) Byrd Polar Research Center, Ohio State University, Columbus, OH, USA |
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Abstract: | We present the results of a marine geophysical investigation of the northern Prince Gustav Channel. By comparative analysis of multibeam bathymetric data, single channel seismic reflection profiles, underway chirp sonar data, ADCP current data and sediment coring, we define the main morphological elements of the area. In particular we define the glacial morphogenesis in relation to the excavation of inner shelf basins and troughs along structural discontinuities and lithologic boundaries. We identify streamlined surfaces that testify to the grounding of ice and past ice flow directions. These glacial forms are found only on glacial tills preserved in the deepest part of the basins, while net erosion to bedrock has occurred elsewhere. Since the Last Glacial Maximum (LGM), the relict glacial morphology has been draped by hemipelagic and diatomaceous mud, and bottom currents have played a major role in focusing sedimentation within small depocentres, that we define as contouritic drifts. Based on shallow sediment architecture and supported by direct measurements, we propose that the direction of bottom water flow is from the outer shelf into the Prince Gustav channel as a result of a combination of tidal currents and ice shelf-related thermohaline circulation. |
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Keywords: | Antarctica contourite drifts glacial morphology Prince Gustav Channel Weddell Sea |
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