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| Titel |
Pacific plate slab pull and intraplate deformation in the early Cenozoic |
| VerfasserIn |
N. P. Butterworth, R. D. Müller, L. Quevedo, J. M. O'Connor, K. Hoernle, G. Morra |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2014-08-06), S.757-777 |
| Datensatznummer |
250115324
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| Publikation (Nr.) |
 copernicus.org/se-5-757-2014.pdf |
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| Zusammenfassung |
| Large tectonic plates are known to be susceptible to internal
deformation, leading to a~range of phenomena including intraplate
volcanism. However, the space and time dependence of intraplate
deformation and its relationship with changing plate boundary
configurations, subducting slab geometries, and absolute plate
motion is poorly understood. We utilise a buoyancy-driven Stokes
flow solver, BEM-Earth, to investigate the contribution of
subducting slabs through time on Pacific plate motion and
plate-scale deformation, and how this is linked to intraplate
volcanism. We produce a series of geodynamic models from 62 to
42 Ma in which the plates are driven by the attached subducting
slabs and mantle drag/suction forces. We compare our modelled
intraplate deformation history with those types of intraplate
volcanism that lack a clear age progression. Our models suggest
that changes in Cenozoic subduction zone topology caused intraplate
deformation to trigger volcanism along several linear seafloor
structures, mostly by reactivation of existing seamount chains, but
occasionally creating new volcanic chains on crust weakened by
fracture zones and extinct ridges. Around 55 Ma, subduction of the
Pacific-Izanagi ridge reconfigured the major tectonic forces acting
on the plate by replacing ridge push with slab pull along its
northwestern perimeter, causing lithospheric extension along
pre-existing weaknesses. Large-scale deformation observed in the
models coincides with the seamount chains of Hawaii, Louisville,
Tokelau and Gilbert during our modelled time period of 62 to
42 Ma. We suggest that extensional stresses between 72 and 52 Ma
are the likely cause of large parts of the formation of the Gilbert
chain and that localised extension between 62 and 42 Ma could cause
late-stage volcanism along the Musicians volcanic ridges. Our models
demonstrate that early Cenozoic changes in Pacific plate driving
forces only cause relatively minor changes in Pacific absolute plate
motion directions, and cannot be responsible for the Hawaiian–Emperor bend
(HEB), confirming previous interpretations that the 47 Ma HEB does
not primarily reflect an absolute plate motion event. |
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