HR: 1340h
AN: T43B-1407    [Abstracts]
TI: Extending Thickened Continental Crust: Implications for the Transantarctic Mountains and West Antarctic Rift System
AU: * Bialas, R W
EM: rbialas@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Buck, W R
EM: buck@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Studinger, M
EM: mstuding@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Fitzgerald, P G
EM: pgfitzge@syr.edu
AF: Department of Earth Sciences of Syracuse University, Heroy Geology Laboratory Syracuse University, Syracuse, NY 13244-1070 United States
AB: The Transantarctic Mountains (TAM) are often described as the largest rift related mountains in the world. They define the western edge of the West Antarctic rift system (WARS) and are usually assumed to have uplifted in the Eocene during a phase of rapid denudation associated with Eocene rifting in the WARS. Previous models have difficulty reconciling large uplift of the TAM with distributed extension of the WARS. We propose a model where the TAM represents an edge of a plateau comprising parts of East and West Antarctica and New Zealand that retains significant elevation, even as the plateau is lowered and extended during the Cretaceous WARS rifting event. Regional scale two-dimensional numerical models are presented showing a layer of thickened continental crust and adjacent crust of normal thickness underlain by a mantle layer extended by pulling at the edges. The temperature-dependent viscous rheology is based on power-law creep flow law for diabase. Temperature profiles are calculated using conductive heat transport and radiogenic heat production that decreases exponentially with depth. Temperature profiles are altered by varying the bottom mantle heat flow and thermal conductivities within acceptable ranges. Different styles of extension including core complex, wide rifting, and narrow rifting are observed for different temperature structures. In the models, a remnant edge, analogue to the ancestral TAM, are observed.
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005