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| Titel |
Subduction obliquity as a prime indicator for geotherm in subduction zone |
| VerfasserIn |
Alexis Plunder, Cedric Thieulot, Douwe van Hinsbergen |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124947
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| Publikation (Nr.) |
 EGU/EGU2016-4458.pdf |
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| Zusammenfassung |
| The geotherm of a subduction zone is thought to vary as a function of subduction rate and the
age of the subducting lithosphere. Along a single subduction zone the rate of subduction can
strongly vary due to changes in the angle between the trench and the plate convergence
vector, namely the subduction obliquity. This phenomenon is observed all around
the Pacific (i.e., Marianna, South America, Aleutian…). However due to observed
differences in subducting lithosphere age or lateral convergence rate in nature, the
quantification of temperature variation due to obliquity is not obvious. In order to
investigate this effect, 3D generic numerical models were carried out using the finite
element code ELEFANT. We designed a simplified setup to avoid interaction with
other parameters. An ocean/ocean subduction setting was chosen and the domain
is represented by a 800 × 300 × 200 km Cartesian box. The trench geometry is
prescribed by means of a simple arc-tangent function. Velocity of the subducting
lithosphere is prescribed using the analytical solution for corner flow and only the energy
conservation equation is solved in the domain. Results are analysed after steady state is
reached.
First results show that the effect of the trench curvature on the geotherm with respect to
the convergence direction is not negligible. A small obliquity yields isotherms which are
very slightly deflected upwards where the obliquity is maximum. With an angle of
∼30∘, the isotherms are deflected upwards of about 10 kilometres. Strong obliquity
(i.e., angles from 60∘ to almost 90∘) reveal extreme effects of the position of the
isotherms. Further model will include other parameter as the dip of the slab and
convergence rate to highlight their relative influence on the geotherm of subduction zone. |
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