 |
| Titel |
Plume-induced subduction initiation: dynamics and significance for modern and early Earth |
| VerfasserIn |
Taras Gerya, Robert Stern, Marzieh Baes, Stephan Sobolev, Scott Whattam |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103584
|
| Publikation (Nr.) |
 EGU/EGU2015-5366.pdf |
|
|
|
|
|
| Zusammenfassung |
| Subduction initiation scenarios can be markedly different in case of globally active vs. globally absent plate tectonics. Most present-day subduction initiation mechanisms require acting plate forces and/or preexisting zones of lithospheric weakness, which are themselves the consequence of plate tectonics (Stern 2004). In contrast, spontaneous plume-induced subduction initiation - suggested on the basis of numerical thermo-mechanical experiments (Ueda et al., 2008) and supported by data re-interpretation of how subduction started in Late Cretaceous time around the Caribbean LIP (Whattam and Stern, 2015) - does not require pre-existing lithospheric fabric, such as are created by active plate tectonics and is viable for both stagnant lid and mobile/deformable lid conditions. Here, we present results of high-resolution 3D numerical thermo-mechanical modeling of plume-induced subduction resulting from tectono-magmatic interaction of an ascending thermal mantle plume with old, cold, dense oceanic lithosphere. We demonstrate that weakening of the strong lithosphere by plume-induced magmatism is the key factor enabling subduction initiation around the plume head. A large plume head is required to overcome ring confinement by slab tearing, and subduction initiation is further favored when plume activity and lithospheric weakening continues for several tens of Ma. We further discuss possible implications of this scenario for modern plate tectonics as well as for plate tectonics initiation in the early Earth.
References
Stern, R.J., 2004. Subduction initiation: spontaneous and induced. EPSL 226, 275-292.
Ueda, K., Gerya, T., Sobolev, S.V., 2008. Subduction initiation by thermal–chemical plumes. PEPI 171, 296-312.
Whattam, S.A., Stern, R. 2015. Late Cretaceous plume-induced subduction initiation along the southern margin of the Caribbean and NW South America: The first documented example with implications for the onset of plate tectonics. Gondwana Research, 27, 38-63. |
|
|
|
|
|
|