The Antarctic Peninsula Pacific margin; modelling flexure and decompaction with constraints from ODP Leg 178 initial results

Author(s): Camerlenghi, Angelo; Rebesco, Michele; De Santis, Laura; Volpi, Valentina; De Rossi, Alessandra
Author Affiliation(s): Primary:
Istituto Nazionale di Oceanografiae di Geofisica Sperimentale, Trieste, Italy
Universita di Trieste, Italy
Volume Title: Antarctica at the close of a millennium; proceedings of the 8th international symposium on Antarctic earth sciences
Volume Author(s): Gamble, John A., editor; Skinner, David N. B.; Henrys, Stuart A.
Source: Bulletin - Royal Society of New Zealand, Vol.35, p.261-267; 8th international symposium on Antarctic earth sciences, Wellington, New Zealand, July 5-9, 1999, edited by John A. Gamble, David N. B. Skinner and Stuart A. Henrys. Publisher: The Royal Society of New Zealand, Wellington, New Zealand. ISSN: 0370-6559. ISBN: 1877264067 CODEN: RNZBAY
Note: In English. 32 refs.; illus., incl. sects., 1 table, geol. sketch maps
Summary: We attempt to explain why the seafloor profile that presumably existed before the advance of grounded ice on the Antarctic Peninsula continental shelf changed from seaward-dipping to the present-day landward-dipping and overdeepened profile. Paleobathymetric profiles and past internal configuration of the margin are calculated by reverse modelling starting from a cross-section derived from a depth-converted multichannel seismic profile, in which the boundaries between units of marked geometric difference have been identified and digitised. The reverse modelling includes sediment decompaction and isostatic compensation after progressive removal of each sedimentary unit, and recovery of the post-rift thermal subsidence. We present the initial results of these these models and sensitivity tests obtained with the age constraints available from the initial results of ODP Leg 178. We conclude that the outer shelf became overdeepened with a landward-dipping profile at c. 4.5 Ma (early Pliocene), coinciding with the onset of progradation and aggradation, a major break in the margin's architecture.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 20 Geophysics, Applied; Aggradation; Antarctic Peninsula; Antarctic ice sheet; Antarctica; Cenozoic; Continental margin; Cores; Decompaction; Geophysical methods; Geophysical profiles; Geophysical surveys; Leg 178; Marine environment; ODP Site 1103; Ocean Drilling Program; Paleo-oceanography; Paleobathymetry; Paleogeography; Seismic methods; Seismic profiles; Seismic stratigraphy; Southern Ocean; Stratigraphic boundary; Surveys; West Antarctica
Coordinates: S635300 S635300 W0654221 W0654221
S634808 S634808 W0655128 W0655128
S635958 S635958 W0652755 W0652755
Record ID: 2004033447
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