HR: 1340h
AN: U43B-0831    [Abstracts]
TI: Active Tectonics of the western Mediterranean: GPS evidence for roll back of a delaminated subcontinental lithospheric slab beneath the Rif Mountains, Morocco.
AU: * Vernant, P
EM: vernant@mit.edu
AF: Dept. of Earth, Atmospheric, and Planetary Sciences, MIT, 77 Massachusetts Ave, Cambridge, MA 02139 United States
AU: Fadil, A
EM: fadil@mit.edu
AF: Dept. of Civil Engineering, LAPR, Mohammadia School of Engineering, Ibn Sina Avenue, Agdal, Rabat, 765 Morocco
AU: McClusky, S
EM: simon@mit.edu
AF: Dept. of Earth, Atmospheric, and Planetary Sciences, MIT, 77 Massachusetts Ave, Cambridge, MA 02139 United States
AU: Reilinger, R
EM: reilinge@erl.mit.edu
AF: Dept. of Earth, Atmospheric, and Planetary Sciences, MIT, 77 Massachusetts Ave, Cambridge, MA 02139 United States
AU: Gomez, F
EM: fgomez@missouri.edu
AF: Dept. of Geological Sciences, University of Missouri, 101 Geology Building, Columbia, MO 65211 United States
AU: Ben Sari, D
EM: fadil@mit.edu
AF: Dept. of Civil Engineering, LAPR, Mohammadia School of Engineering, Ibn Sina Avenue, Agdal, Rabat, 765 Morocco
AU: Mourabit, T
EM: tmourabit@menara.ma
AF: Dept. of Geology, Abdelmalek Essaadi University, Route de Ziaten, Tangier, 416 Morocco
AU: Feigl, K
EM: Kurt.Feigl@numericable.fr
AF: Dept. of Terrestrial and Planetary Dynamics, CNRS, Obs. Midi-Pyrenees, Toulouse, 31400 France
AU: Barazangi, M
EM: mb44@cornell.edu
AF: Dept. of Geological Sciences, Cornell University, Snee Hall, Ithaca, NY 14853 United States
AB: The location and character of the Africa-Eurasia plate boundary in the western Mediterranean remain equivocal. Miocene to present extension of the interplate Alboran domain occurs within the context of ongoing Africa-Eurasia convergence. Ideas to explain the apparently synchronous subsidence of the Alboran Sea and uplift of the adjacent Betic and Rif mountain belts are still widely debated. To understand better the tectonics of this region, we determine the surface deformation in Morocco from five years of GPS survey observations of a 22-station survey network, 4 continuously recording GPS stations, and 4 IGS stations in Iberia. In addition to the expected Africa-Eurasia relative motion, the results indicate roughly southward motion (~3 mm/yr) of the Rif Mountains, Morocco relative to stable Africa. The associated crustal shortening of the Rif is balanced by extension and opening of the adjacent Alboran Sea. Motion of the Rif is approximately normal to the direction of Africa-Eurasia relative motion, and is difficult to relate to deformation induced by plate boundary interactions. We suggest that Rif-Alboran deformation is the combination of the differential plate motion between Iberia and Africa, and sub-lithospheric dynamic processes. The continental crust characterizing the Alboran region and the N-S asymmetry of the observed deformation (i.e., no evidence for north-directed shortening in the Betic Mountains north of the Alboran Sea) suggests that delamination and south-directed roll back of the African lithospheric mantle under the Rif/Alboran domain is driving the recent geologic evolution of the westernmost Mediterranean region.
DE: 1209 Tectonic deformation (6924)
DE: 1243 Space geodetic surveys
DE: 8107 Continental neotectonics (8002)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8150 Plate boundary: general (3040)
SC: Union [U]
MN: Fall Meeting 2005