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| Titel |
Numerical models of slab migration in continental collision zones |
| VerfasserIn |
V. Magni, J. Hunen, F. Funiciello, C. Faccenna |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 3, no. 2 ; Nr. 3, no. 2 (2012-09-05), S.293-306 |
| Datensatznummer |
250000988
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| Publikation (Nr.) |
 copernicus.org/se-3-293-2012.pdf |
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| Zusammenfassung |
| Continental collision is an intrinsic feature of plate tectonics. The
closure of an oceanic basin leads to the onset of subduction of buoyant
continental material, which slows down and eventually stops the subduction
process. In natural cases, evidence of advancing margins has been
recognized in continental collision zones such as India-Eurasia and
Arabia-Eurasia. We perform a parametric study of the geometrical and
rheological influence on subduction dynamics during the subduction of
continental lithosphere. In our 2-D numerical models of a free subduction
system with temperature and stress-dependent rheology, the trench and the
overriding plate move self-consistently as a function of the dynamics of the
system (i.e. no external forces are imposed). This setup enables to study
how continental subduction influences the trench migration. We found that in
all models the slab starts to advance once the continent enters the
subduction zone and continues to migrate until few million years after the
ultimate slab detachment. Our results support the idea that the advancing
mode is favoured and, in part, provided by the intrinsic force balance of
continental collision. We suggest that the advance is first induced by the
locking of the subduction zone and the subsequent steepening of the slab,
and next by the sinking of the deepest oceanic part of the slab, during
stretching and break-off of the slab. These processes are responsible for
the migration of the subduction zone by triggering small-scale convection
cells in the mantle that, in turn, drag the plates. The amount of advance
ranges from 40 to 220 km and depends on the dip angle of the slab before the
onset of collision. |
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