Antarctic Science



Papers—Earth Sciences and Glaciology

Bathymetry and acoustic facies beneath the former Larsen-A and Prince Gustav ice shelves, north-west Weddell Sea


Carol J. Pudsey a1, Jeffrey Evans a1, Eugene W. Domack a2, Peter Morris a1 and Rodolfo A. Del Valle a3
a1 British Antarctic Survey, Natural Environmental Research Council, High Cross, Madingley Road, Cambridge CB3 OET, UK
a2 Department of Geology, Hamilton College, 198 College Hill Road, Clinton, NY 13323, USA
a3 Depto. Ciencias de la Tierra, Instituto Antártico Argentino, Cerrito 1248, C1010AAZ Buenos Aires, Argentina

Article author query
pudsey c   [PubMed][Google Scholar] 
evans j   [PubMed][Google Scholar] 
domack e   [PubMed][Google Scholar] 
morris p   [PubMed][Google Scholar] 
valle r   [PubMed][Google Scholar] 

Abstract

We present preliminary results of the first detailied surveys of the former Larsen-A Ice Shelf, Larsen Inlet and southern Prince Gustav Channel, where disintegration of small ice shelves in the past ten years has exposed the seafloor. Glacial troughs in the Larsen-A area, Larsen Inlet and Prince Gustav Channel reach 900–1100 m depth and have hummocky floors. Farther south-east, the continental shelf is shallower (400–500 m) and its surface is fluted to smooth, with the density of iceberg furrowing increasing towards the shelf edge. Acoustic profiles show a drape of transparent sediment 4–8 m thick in Prince Gustav Channel, thinning southwards. In cores, this drape corresponds to diatom-bearing marine and glacial-marine mud. In the Larsen-A area and Larsen Inlet, acoustically opaque sediment includes proximal ice shelf glaciomarine gravelly and sandy muds, and firm to stiff diamicts probably deposited subglacilly. These are overlain by thin (up to 1.3 m) glaciomarine muds, locally with distinctive diatom ooze laminae.

(Received December 30 2000)
(Accepted May 29 2001)


Key Words: echo character; glaciomarine sediment; Larsen Ice Shelf; subglacial sediment; Weddell Sea.


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