Thursday, 30 August 2007 - 4:00 PM
4.P2.D-2

Geophysical survey of the thick, expanded sedimentary filling of the new-born Crane fjord (former Larsen B Ice Shelf, Antarctica)

Fabrizio Zgur1, Michele Rebesco1, Eugene W. Domack2, Amy Leventer3, Stephanie Brachfeld4, and Veronica Willmott2. (1) RIMA, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/C, Sgonico (TS), Italy, (2) Department of Geosciences, Hamilton College, 198 College Hill Rd., Clinton, NY 13323, (3) Geology Department, Colgate University, 13 Oak Drive, Hamilton, NY 13346, (4) Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043

Integrated geophysical data recorded during the NBP0603 research cruise revealed the setting and the infill history of the newly-created Crane Glacier Fjord (Exasperation Inlet, Eastern Antarctic Peninsula). Originated by the 15 km retreat of the Crane Glacier after the Larsen B ice shelf collapse, the fjord shows at its floor three ponded basins, detailly imaged by multibeam echosounder. In the lowest one, sub bottom profiling and single channel seismic evidenced  a 40 m thick, well-layered and unconsolidated filling: its upper part, as confirmed by a 2.7 m core collected in the area, was interpreted as the result of the accelerated ice discharge from the glacier during the ice shelf break-up; the rest of the filling was instead regarded as the result of 30 years long sub-glacial lake sedimentation, suggesting that the glacier behaviour was affected not only by the ice shelf collapse, but also by the regional ice shelves dynamics.

[Manuscript]

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