HR: 1330h
AN: C43A-09    [Abstracts]
TI: Morphological Evolution of Marguerite Bay, Antarctic Peninsula Continental Shelf
AU: * Holloman, J H
EM: holloman@geol.lsu.edu
AU: Bart, P
EM: phil@geol.lsu.edu
AB: The Antarctic Peninsula Pacific margin continental shelf has a distinct trough and bank morphology which was formed in association with discrete zones of fast flowing ice, or ice streams . Rebesco et al. (1998) propose that sediment by-passed the continental shelf at the mouth of ice streams during major advances of grounded ice to the shelf edge during the Quaternary. They argue that prograding upper slopes were constructed on those portions of the shelf margin between major ice streams. The subsurface stratigraphy in the Marguerite Bay area suggests that the continental shelf may have evolved differently than the Rebesco et al. (1998) conceptual model suggests. Seismic data acquired along strike of the Antarctic Peninsula outer shelf shows that deeply buried trough-mouth fans are offset with respect to the modern positions of seafloor troughs. In contrast, trough-mouth fans are absent from the overlying aggradational section. Data from ODP Site 1097 at Marguerite Trough samples massive diamictite within that part of the hole corresponding to the trough-mouth fan and overlying aggradational section. Eyles et al. (2001) interpret these as sub-glacial deposits. Thus, the modern shelf-edge/upper slope morphology is inherited from an earlier time.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
SC: Cryosphere [C]
MN: 2005 Joint Assembly