Januszczak, Nicole; Eyles, Nicholas (2000): Glaciated continental margin processes and stratigraphy; Cenozoic of Antarctica and Neoproterozoic of Rodinia compared. Geological Society of America (GSA), Boulder, CO, United States, In: Anonymous, Geological Society of America, 2000 annual meeting, 32 (7), 305, georefid:2003-052792
Abstract:
The glacially-influenced Cenozoic continental margin of Antarctica shows a large-scale subsurface stratigraphy consisting of flat-lying "topsets" recording episodic aggradation of the continental shelf, that rest on seaward-dipping, wedge-shaped "foresets" formed by progradation of the continental slope. Ocean Drilling Program (ODP) Leg 178 (February-April 1998) drilled two sites (1097, 1103) through the outer Antarctic Peninsula Pacific shelf into strata no older than late Miocene or early Pliocene (<4.6 Ma). "Topset" stratigraphy comprises multiple units (up to 100 m thick) of deformation till recording episodes of ice expansion to the shelf edge and subglacial reworking of marine sediment. Till is interbedded with intervals of stratified and graded diamictites that contain in situ marine biofacies typical of proglacial marine settings and recording ice retreat from the shelf. During ice expansion, shelf sediments are reworked and transported downslope by debris flows allowing the continental slope to prograde as "foresets". ODP Leg 188 (January-March 2000) drilled in Prydz Bay at the downstream end of the Lambert Graben which has served as the principal drainage outlet for the East Antarctic Ice Sheet during the Cenozoic. Site 1166 drilled the mid-continental shelf and recovered the transition, as yet undated, from pre-glacial to glacial conditions. The slope site (1167) in the Prydz Channel Trough Mouth Fan is characterized by debrites separated by thin (>1 m) intervals of hemipelagic and contourite sedimentation. Cenozoic facies and overall stratigraphy of the Antarctic Peninsula and Prydz Bay continental margins are very similar and directly comparable with Neoproterozoic glaciated continental shelf and slope successions that accumulated along the rifting margins of Rodinia after 750 Ma now preserved in Australia and western North America.
Coverage:
West: -78.3000 East: 171.0000 North: -63.4800 South: -90.0000
West: NaN East: NaN North: NaN South: NaN
West: NaN East: NaN North: NaN South: NaN
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