Modeling strain and anisotropy along the Alpine fault, south Island, New Zealand
| Autor: | Andréa Tommasi, Susan Ellis, Martha K. Savage, Jean Chery |
|---|---|
| Přispěvatelé: | Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), David Okaya, Tim Stern, Fred Davey |
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
010504 meteorology & atmospheric sciences Pacific Plate [SDE.MCG]Environmental Sciences/Global Changes Mineralogy Shear wave splitting Crust 010502 geochemistry & geophysics Strike-slip tectonics 01 natural sciences Mantle (geology) Transpression Physics::Geophysics Lithosphere 14. Life underwater Anisotropy Petrology Geology 0105 earth and related environmental sciences New Zealand |
| Zdroj: | A continental plate boundary : tectonics of South Island New Zealand David Okaya; Tim Stern; Fred Davey. A continental plate boundary : tectonics of South Island New Zealand, AGU, pp.289-305, 2007, Geophysical Monograph Series, Volume 175 A Continental Plate Boundary: Tectonics at South Island, New Zealand |
| Popis: | Near-surface deformation between the Australian and Pacific plates in South Island, New Zealand is concentrated in a narrow zone marked by the Alpine Fault, but strong and widespread anisotropy inferred across New Zealand from shear wave splitting suggests diffuse deformation at mantle depths. To constrain this interpretation, we calculate temperature- and stress-dependent strain fields, crystal preferred orientation, anisotropy and resultant shear-wave splitting beneath a lithospheric fault deforming by either pure strike-slip or transpression. In pure strike-slip experiments, strain localizes in the high temperature regions under the thick continental landmass. Under the oceanic regions, which have thin crust, anisotropy is weak (delay times (dt) 1400 km. In transpression experiments that have initial structure based on estimates of the present crustal thickness and temperature, the cold root inhibits strain beneath the fault and leads to anisotropy patterns that do not explain the observations. This suggests that (a) a weak zone in the mantle lithosphere is needed to explain present-day deformation; and (b) most of the anisotropy measured may be "frozen in" from strike-slip deformation that occurred before the present mantle root developed. |
| Databáze: | OpenAIRE |
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