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| Titel |
Robust measurement of anisotropy in the mechanical strength of oceanic lithosphere |
| VerfasserIn |
Lara M. Kalnins, Frederik J. Simons |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149642
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| Publikation (Nr.) |
 EGU/EGU2017-14013.pdf |
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| Zusammenfassung |
| The mechanical strength of the lithosphere, typically measured by analogue to a purely
elastic plate with thickness Te, is a key geodynamic parameter that modulates, and in turn is
modulated by, many key tectonic processes, including rifting, orogeny, and volcanism. The
anisotropy inherent in these processes leads to a natural expectation that the resulting material
strength of the lithosphere may also be anisotropic, which will in turn influence future
deformation and volcanic activity.
Anisotropy in the strength of continental lithosphere has been studied by a range of
authors, but anisotropy in oceanic Te remains nearly unstudied, despite the highly anisotropic
nature of its formation at mid-ocean ridges. Here, we extend our robust analysis of anisotropy
in continental Te (Kalnins et al., 2015) to the oceanic domain. We look to develop a robust
method optimised for oceanic structure and datasets that consistently identifies and removes
spurious measurements of anisotropy, leaving only those directions that are both
mathematically and geophysically significant. We compare results from free-air
admittance, more commonly used in the oceans, with Bouguer coherence, widely used in
the continents, and hence used for previous studies of anisotropy in Te. We also
consider the influence of different available marine datasets, particularly the use
of bathymetry datasets that include gravity-derived data. Accurately identifying
anisotropy in the strength of the oceanic lithosphere is key in understanding how
spreading rate, fracture zone dynamics, and flow in the upper mantle, as well as normal
maturation of oceanic lithosphere, influence the evolving strength profile of the
lithosphere. Anisotropy may also have a role to play in how intraplate volcanism and
subduction both influence and are influenced by the strength of the local lithosphere. |
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