HR: 08:45h
AN: T51E-04    [Abstracts]
TI: Buoyancy-Driven Deformations and Contemporary Tectonic Stress in the Lithosphere Beneath North-Central Italy
AU: Aoudia, K
EM: aoudia@dst.units.it
AF: SAND Group, the Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste, 34100 Italy
AU: Aoudia, K
EM: aoudia@dst.units.it
AF: Dipartimento di Scienze della Terra, Università degli Studi di Trieste, via E. Weiss 1, Trieste, 34127 Italy
AU: * Ismail-Zadeh, A
EM: aismail@mitp.ru
AF: SAND Group, the Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste, 34100 Italy
AU: * Ismail-Zadeh, A
EM: aismail@mitp.ru
AF: International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Warshavskoye sh. 79-2, Moscow, 117556 Russian Federation
AU: * Ismail-Zadeh, A
EM: aismail@mitp.ru
AF: Geophysikalisches Institut, Universitaet Karlsruhe, Hertzstr. 16, Karlsruhe, 76187 Germany
AU: Panza, G
EM: panza@dst.units.it
AF: SAND Group, the Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste, 34100 Italy
AU: Panza, G
EM: panza@dst.units.it
AF: Dipartimento di Scienze della Terra, Università degli Studi di Trieste, via E. Weiss 1, Trieste, 34127 Italy
AB: The juxtaposed contraction and extension, a long-standing geological enigma recognized in the Italian Peninsula, has for a long time attracted the attention of geoscientists. Several models, invoking mainly external forces, have been put forward to explain the close association of these two end-member deformation mechanisms clearly observed by geophysical, geodetic and geological investigations. These models appeal to interactions along plate margins or at the base of the lithosphere such as back-arc extension or shear tractions from mantle flow or to subduction processes such as slab roll back, retreat or pull and detachment. We combined seismic data from Central Italy to image the crust and upper mantle and thus to understand the complex lithospheric deformations observed in the Apennines. The well developed low velocity zone in the uppermost mantle between the crust and the underlying continental lithosphere supports the lithospheric delamination beneath the peninsula and provides a new unifying background for geophysical, petrological and geochemical studies of recent magmatism and volcanism. The rate of the modeled lithospheric movement is in agreement with GPS data. The pattern of the movement can explain the heat flux and the regional geology and provide a new background for the genesis and age of the recent Tuscan magmatism. The modeled stress in the lithosphere is spatially correlated with gravitational potential energy patterns and show that internal buoyancy forces, solely, can explain the coexisting regional contraction and extension and the unusual intermediate depth seismicity.
DE: 9335 Europe
DE: 8102 Continental contractional orogenic belts
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 8164 Stresses--crust and lithosphere
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting