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Morphology and stratal geometry of the Antarctic continental shelf : insights from models

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dc.contributor.author ten Brink, Uri S.
dc.contributor.author Schneider, Christopher
dc.contributor.author Johnson, Aaron H.
dc.date.accessioned 2007-05-02T15:56:54Z
dc.date.available 2007-05-02T15:56:54Z
dc.date.issued 1995
dc.identifier.citation Geology and Seismic Stratigraphy of the Antarctic Margin, edited by Peter F. Barker and Alan K. Cooper, :1-24. Washington, DC: American Geophysical Union, 1995 en
dc.identifier.uri http://hdl.handle.net/1912/1602
dc.description This paper is not subject to U.S. copyright. The definitive version was published in Geology and Seismic Stratigraphy of the Antarctic Margin, edited by Peter F. Barker and Alan K. Cooper, :1-24. Washington, DC: American Geophysical Union, 1995. ISBN: 0875908845. doi:10.1029/AR068p0001 en
dc.description.abstract Reconstruction of past ice-sheet fluctuations from the stratigraphy of glaciated continental shelves requires understanding of the relationships among the stratal geometry, glacial and marine sedimentary processes, and ice dynamics. We investigate the formation of the morphology and the broad stratal geometry of topsets on the Antarctic continental shelf with numerical models. Our models assume that the stratal geometry and morphology are principally the results of time-integrated effects of glacial erosion and sedimentation related to the location of the seaward edge of the grounded ice. The location of the grounding line varies with time almost randomly across the shelf. With these simple assumptions, the models can successfully mimic salient features of the morphology and the stratal geometry. The models suggest that the current shelf has gradually evolved to its present geometry by many glacial advances and retreats of the grounding line to different locations across the shelf. The locations of the grounding line do not appear to be linearly correlated with either fluctuations in the δ180 record (which presumably represents changes in the global ice volume) or with the global sea-level curve, suggesting that either a more complex relationship exists or local effects dominate. The models suggest that erosion of preglacial sediments is confined to the inner shelf, and erosion decreases and deposition increases toward the shelf edge. Some of the deposited glacial sediments must be derived from continental erosion. The sediments probably undergo extensive transport and reworking obliterating much of the evidence for their original depositional environment. The flexural rigidity and the tectonic subsidence of the underlying lithosphere modify the bathyrnetry of the shelf, but probably have little effect on the stratal geometry. Our models provide several guidelines for the interpretation of unconformities, the nature of preserved topset deposits, and the significance of progradation versus aggradation of shelf sediments. en
dc.description.sponsorship Supported by NSF grant OPP-20462 and the U.S. Geological Survey Marine and Coastal Program. en
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher American Geophysical Union en
dc.relation.uri http://dx.doi.org/10.1029/AR068p0001
dc.title Morphology and stratal geometry of the Antarctic continental shelf : insights from models en
dc.type Book chapter en
dc.identifier.doi 10.1029/AR068p0001


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