Kinematics and magmatism of slab tear faults

Rosenbaum, G., Gasparon, M., Lucente, F. P., Peccerillo, A. and Miller, M. S. (2008). Kinematics and magmatism of slab tear faults. In: 2008 Western Pacific Geophysics Meeting, Cairns, Australia, (). 29 July - 1 August 2008.

Author Rosenbaum, G.
Gasparon, M.
Lucente, F. P.
Peccerillo, A.
Miller, M. S.
Title of paper Kinematics and magmatism of slab tear faults
Conference name 2008 Western Pacific Geophysics Meeting
Conference location Cairns, Australia
Conference dates 29 July - 1 August 2008
Publication Year 2008
Sub-type Poster
Language eng
Abstract/Summary Tectonic activity in convergent plate boundaries commonly involves backward migration (rollback) of narrow subducting slabs and segmentation of subduction zones through slab tearing. In this study, we combined seismic tomography data and kinematic reconstructions to obtain a deeper insight into the complex geodynamics of Italian magmatism. Seismic tomography results show gaps within the subducting lithosphere, which are interpreted as deep (100-500 km) sub-vertical tear faults. The development of such tear faults is consistent with proposed kinematic reconstructions, in which different rates of subduction rollback affected different parts of the subduction zone. Our model shows that tear faulting and slab breakoff played a fundamental role in controlling the temporal and spatial distribution of young (<10 Ma) magmatism in Italy and the Tyrrhenian Sea. We recognize that magmatic activity induced by tear faulting was a transitional phase between subduction-related arc magmatism and post- collisional magmas related to slab breakoff. This tectono-magmatic evolution marks the destruction of subduction zones, indicating the fate of subducting slabs following continental collision. The magmatic signature associated with tear faulting is important because it can considerably enhance our ability to reconstruct modern and ancient convergent plate boundaries. Tear faults, unlike strike-slip faults that are associated with oblique collision or indentation, are characterized by magmatic activity induced by upwelling of asthenospheric material. Their geometry is attained by tearing and segmentation of lithospheric slabs during subduction rollback. In most retreating plate boundaries, this process is inevitable. This is because the subducting lithosphere is not uniform but typically consists of numerous seamounts, oceanic plateaus, aseismic ridges and continental fragments. Since these lithospheric anomalies are relatively buoyant, their arrival at the subduction zone is likely to impede subduction rollback, thus dividing the subduction zone into segments of different rollback velocities.
Subjects 0403 Geology
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes abstract number: T35A-06

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Created: Thu, 11 Mar 2010, 14:07:19 EST by Laura McTaggart on behalf of Faculty of Science