One dimensional backstripping results from IODP Expedition 318, Site U1356; tectonic implications for the Wilkes Land margin of Antarctica

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Author(s): Hayden, T. G.; Kominz, Michelle A.; González, J. J.; Escutia, C.; Brinkhuis, H.
International Ocean Discovery Program, Expedition 318 Scientific Party of International Ocean Discovery Program Expedition 318
Author Affiliation(s): Primary:
Western Michigan University, Department of Geosciences, Kalamazoo, MI, United States
Universidad de Granada, Spain
Utrecht University, Netherlands
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The Wilkes Land margin of Antarctica is the conjugate margin of the Great Australian Bight, which underwent extension, thinning and rifting from ∼160 Ma until breakup at ∼83 Ma. Both Wilkes Land and the Great Australian Bight are considered passive margins, and were thought to be tectonically inactive since breakup at 83 Ma. We have backstripped the U1356 Core recovered from the continental rise off Wilkes Land, Antarctica by IODP Expedition 318. Backstripping input included lithological and sedimentary analysis, paleo-environmental indicators, combined paleomagnetic and biostratigraphic chronologies, and physical properties measurements. Tectonic subsidence shows a major event between 50 and 33.6 Ma, a time represented by a hiatus in the U1356 core. The magnitude of subsidence requires it to be tectonic in origin, and the timing matches with a reorganization of plate motions that represents the transition from slow spreading to fast spreading between Antarctica and Australia, which occurred at approximately 43 Ma. Coupled with a regional seismic framework, and using other Expedition 318 site analyses, the Wilkes Land margin is shown to be far more complex then the simple passive margin currently assumed. We explore several possible mechanisms for the subsidence and erosion observed; including thermal uplift due to continental insulation of the asthenosphere and it's interaction with a recently rifted margin, asthenospheric convection, transtensional or transpressional basin development and loading, and edge-driven asthenospheric convection.
Year of Publication: 2011
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 18 Geophysics, Solid-Earth; Antarctica; Asthenosphere; Biostratigraphy; Conjugate margins; Continental margin; Continental rise; Convection; Cores; Expedition 318; Great Australian Bight; IODP Site U1356; Indian Ocean; Integrated Ocean Drilling Program; Mapping; Measurement; Motions; Ocean floors; Paleoenvironment; Paleomagnetism; Passive margins; Physical properties; Plate tectonics; Seismicity; Southern Ocean; Subsidence; Tectonics; Transpression; Wilkes Land
Coordinates: S631837 S631837 E1355956 E1355956
Record ID: 2015105220
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