HR: 0800h
AN: T31C-1323    [Abstracts]
TI: Crust-Mantle Dynamics of the Salton Block, Eastern Transverse Ranges, Southern California
AU: * Fay, N P
EM: nfay@newberry.uoregon.edu
AF: University of Oregon, Department of Geological Sciences, Eugene, OR 97403 United States
AU: Humphreys, E D
EM: gene@newberry.uoregon.edu
AF: University of Oregon, Department of Geological Sciences, Eugene, OR 97403 United States
AB: Active crustal deformation in the Eastern Transverse Ranges and Salton Trough region of southern California is a combination of horizontal strike-slip faulting, mountain building, and extensional basin formation. The stresses necessary to drive the relative motion of crustal blocks and vertical deformation are either transmitted laterally across faults or from below by an actively deforming mantle, or by some combination of the two mechanisms. The tomographically imaged high-velocity anomaly beneath the Transverse Ranges presumably represents converging and downwelling lithospheric mantle that, if strongly coupled to the upper crust, would drive upper crustal deformation. We find evidence for a relatively strong, high viscosity lower crust from numerical kinematic models of geodetic data and present preliminary dynamic models of the forces acting on the Salton block which address the roles of stresses due to topography, fault strength and crust-mantle coupling.
DE: 8110 Continental tectonics--general (0905)
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 8159 Rheology--crust and lithosphere
DE: 8164 Stresses--crust and lithosphere
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting