HR: 0800h
AN: T31C-0586    [Abstracts]
TI: Sequential Development of Interfering Metamorphic Core Complexes: Numerical Experiments and Comparison to the Cyclades, Greece
AU: * Tirel, C
EM: c.tirel@geo.uu.nl
AF: Tectonophysics Group, Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Gautier, P
EM: pierre.gautier@univ-rennes1.fr
AF: Geosciences Rennes UMR 6118 CNRS, Universite de Rennes 1, 263 Avenue du General Leclerc CS 74205, Rennes cedex, 35042, France
AU: van Hinsbergen, D
EM: hins@geo.uu.nl
AF: Paleomagnetic Laboratory ‘Fort Hoofddijk', Department of Earth Sciences, Utrecht University, Budapestlaan 17, Utrecht, 3584 CD, Netherlands
AU: Wortel, R
EM: wortel@geo.uu.nl
AF: Tectonophysics Group, Faculty of Geosciences, Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AB: The Cycladic extensional province (Greece) contains classical examples of metamorphic core complexes (MCCs), where exhumation was accommodated along multiple interfering and/or sequentially developed syn- and antithetic extensional detachment zones. Previous studies on the development of MCCs did not take into account the possible interference between multiple and closely spaced MCCs. In the present study, we have performed new lithosphere-scale experiments in which the deformation is not a priori localized so as to explore the conditions of the development of several MCCs in a direction parallel to extension. In a narrow range of conditions, MCCs are closely spaced, interfere with each other, and develop in sequence. From a comparison between numerical results and geological observations, we find that the Cyclades metamorphic core complexes are in good agreement with the model in terms of Moho geometry and depth, kinematic and structural history, timing and duration of core complex formation and metamorphic history. We infer that, for Cycladic MCC-type to develop, an initial crustal thickness prior to the onset of post-orogenic extension between 40 and 44 km, a boundary velocity close to 2 cm/yr and an initial thermal lithospheric thickness of about 60 km are required. The latter may be explained by a significant heating due to delamination of subducting continental crust or vigorous small-scale thermal convection.
DE: 8109 Continental tectonics: extensional (0905)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting