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| Titel |
Challenges (and Promise) of In-Situ Lithospheric Rheology from Isostatic Strength Analyses |
| VerfasserIn |
Anthony R. Lowry, Thorsten W. Becker, Janine S. Buehler, Meghan S. Miller, Marta Pérez-Gussinyé, Derek L. Schutt, Lisa L. Seunarine |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077491
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| Zusammenfassung |
| Measurements of effective elastic thickness, Te, from flexural isostatic modeling are sensitive
to flow rheology of the lithosphere. Nevertheless Te has not been widely used to estimate
in-situ rheology, partly owing to methodological questions regarding the measurement of Te
and partly because of uncertainties in other in-situ properties of temperature, composition,
water content and state-of-stress of the lithosphere. Dense seismic and other geophysical
arrays such as EarthScope’s USArray are providing a wealth of new information about
physical state of the lithosphere, however, and the relationships of these data to
Te promises new insights into lithospheric rheology and deformation processes.
For example, new estimates of subsurface mass distributions derived from seismic
data enable us to examine various controversial assumptions about the nature of
lithospheric loads. Variations in crustal composition evident in bulk crustal velocity
ratio, vP-vS, contribute a surprisingly large fraction of total loading, and elevation
models better match observations if Moho flexure is not forced to match surface
flexure, indicating that lower crustal flow and other crustal mass transfer processes are
significant. Perhaps the most interesting new information on physical state derives
from imaging of uppermost mantle velocities using refracted mantle phases, Pn
and Sn, and depths to negative velocity gradients imaged as converted phases in
receiver functions (seismic lithosphere-asthenosphere boundary, “LAB”). We will
compare Te measurements to thermal models derived from these seismic fields, and
discuss their implications for lithospheric rheological controls and thermal processes. |
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