HR: 14:10h
AN: T23E-03 INVITED    [Abstracts]
TI: Terminal Stage Subduction and Slab Detachment: From Structure to Dynamics
AU: * Wortel, M J
EM: wortel@geo.uu.nl
AF: Department of Earth Sciences, Faculty of Geosciences, Utrecht University, PO Box 80021, Utrecht, 3508 TA, Netherlands
AU: Spakman, W
EM: wims@geo.uu.nl
AF: Department of Earth Sciences, Faculty of Geosciences, Utrecht University, PO Box 80021, Utrecht, 3508 TA, Netherlands
AU: Govers, R
EM: govers@geo.uu.nl
AF: Department of Earth Sciences, Faculty of Geosciences, Utrecht University, PO Box 80021, Utrecht, 3508 TA, Netherlands
AB: In this contribution we focus on terminal stage subduction, often triggered by continent-continent or arc-continent collision. Rupturing of subducted lithosphere, including slab detachment, is a key process in this stage. Seismic tomography information on the 3D structure of subduction zones has been key towards developing a better understanding of subduction processes. We show how structural information on lithosphere and mantle structure, obtained from seismic tomography, can be used to formulate hypotheses concerning the evolution and dynamics of subduction zones which (1) can be subjected to numerical modeling to investigate the physical soundness of the hypotheses, and (2) can subsequently be tested against geological, geophysical, and geodetical data to assess their general or regional validity. In combination, this approach increases our understanding of the relation between deep processes and the geological processes at the surface. The landlocked basin setting of the Mediterranean region provides unique opportunities to study terminal stage subduction and its consequences. Subducted lithosphere is subject to various types of rupturing: Slab detachment, vertical slab tearing and the formation of STEP (tear) faults have been identified and analysed. The different Mediterranean arc systems being in slightly different stages of evolution provides additional clues towards unraveling the dynamics of the process. Using examples from the western-central and eastern Mediterranean, we show how temporal and spatial variations in slab structure affect the dynamics and stress field of convergent plate boundaries, with arc migration and back-arc extension as a prominent expression. In addition, terminal stage subduction appears to be have played a crucial role in Italian magmatism. Terminal stage subduction involving slab detachment is a strongly transient stage with great impact on geological processes, on a wide variety of scales. The information obtained from Mediterranean subduction zone studies sheds light on the evolution of other and/or older convergent plate margins, as well.
DE: 8100 TECTONOPHYSICS
DE: 8104 Continental margins: convergent
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
DE: 8178 Tectonics and magmatism
DE: 8180 Tomography (6982, 7270)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting