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| Titel |
Mantle flow and dynamic topography associated with slab window opening |
| VerfasserIn |
Benjamin Guillaume, Monica Moroni, Francesca Funiciello, Joseph Martinod, Claudio Faccenna |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038408
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| Zusammenfassung |
| A slab window is defined as an “hole” in the subducting lithosphere. In the classical view,
slab windows develop where a spreading ridge intersects a subduction zone. The main
consequences of this phenomenon are the modifications of the physical, chemical and thermal
conditions in the backarc mantle that in turn affect the tectonic and magmatic evolution of the
overriding plate. In this work, we perform dynamically self-consistent mantle-scale
laboratory models, to evaluate how the opening of a window in the subducting
panel influences the geometry and the kinematics of the slab, the mantle circulation
pattern and, finally, the overriding plate dynamic topography. The adopted setup
consists in a two-layer linearly viscous system simulating the roll-back of a fixed
subducting plate (simulated using silicone putty) into the upper mantle (simulated using
glucose syrup). Our experimental setting is also characterized by a constant-width
rectangular window located at the center of a laterally confined slab, modeling the
case of the interaction of a trench-parallel spreading ridge with a wide subduction
zone.
We find that the geometry and the kinematics of the slab are only minorly affected by the
opening of a slab window. On the contrary, slab induced mantle circulation, quantified using
Feature Tracking image analysis technique, is strongly modified and produces a
peculiar non-isostatic topographic signal on the overriding plate. Assuming that our
modeling results can be representative of the natural behavior of subduction zones, we
compare them to the Patagonian subduction zone finding that anomalous backarc
volcanism that developed since middle Miocene could result from the lateral flowage of
subslab mantle, and that part of the Patagonian uplift could be dynamically supported. |
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