HR: 14:25h
AN: T32D-04    [PDF]
TI: Gravitational Load Shedding and Metamorphic Core Complex Development
AU: * Pearse, J
EM: pearse@physics.utoronto.ca
AF: Department of Physics, University of Toronto, 60 St George St., Toronto, ON M5S 1A7 Canada
AU: Bailey, R C
EM: bailey@physics.utoronto.ca
AF: Departments of Physics and Geology, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 Canada
AB: A number of competing theories have attempted to explain the domical or archlike features in the Basin and Range Province (BRP) known as metamorphic core complexes. While current consensus attributes their formation to Mid-Tertiary extension, the formation of some core complexes may have predated this extension and the mechanisms leading to uplift of the cores remain controversial. Current models appeal to isostatic uplift of lower crustal material in response to some form of tectonic denudation. We investigate an alternative mechanism, independent of Basin and Range extension, which may contribute dynamically to the formation of some core complexes in this region. Thermally induced thinning of the elastic crust can lead to the subsidence of anomalously dense material previously supported by elastic stresses. The upper crust in the BRP is sufficiently thin that runaway subsidence, followed by shedding of the dense load, is plausible for geologically reasonable loads. The subsequent uplift due to stored elastic stresses in the crust and the buoyancy of lighter material entrained into the lower crust by the sinking load could give rise to features and topography consistent with those of BRP core complexes.
DE: 3210 Modeling
DE: 8110 Continental tectonics--general (0905)
DE: 8120 Dynamics of lithosphere and mantle--general
SC: Tectonophysics [T]
MN: 2003 Fall Meeting