Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/7160
Authors: | Doglioni, C.* Ismail-Zadeh, A.* Panza, G.* Riguzzi, F.* |
Title: | Lithosphere–asthenosphere viscosity contrast and decoupling | Journal: | Physics of the Earth and Planetary Interiors | Series/Report no.: | /189 (2011) | Publisher: | Elsevier | Issue Date: | Nov-2011 | DOI: | 10.1016/j.pepi.2011.09.006 | URL: | http://www.sciencedirect.com/science/article/pii/S0031920111001889 | Keywords: | Lithosphere dynamics Asthenosphere Viscosity contrast Decoupling Analytical modelling Rayleigh–Taylor instability |
Subject Classification: | 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous | Abstract: | The coupling/decoupling between the lithosphere and asthenosphere has significant implications for understanding many important aspects of plate tectonics and geodynamics. To drive plate motion, mantle convection requires coupling at the lithosphere–asthenosphere (LA) interface. Meanwhile a low viscosity layer in the asthenosphere is indicative of possible LA decoupling. Here we present an analytical model of a stratified uppermost mantle structure disturbed by a long-wavelength perturbation (such as the body tide) to analyse the influence of LA viscosity contrast on the growth (or decay) rates of the perturbation. We show that the viscosity contrast of 8–10 orders of magnitude would allow a relative motion of the lithosphere over the asthenosphere due to the long-wavelength perturbations at the rate of about 10 cm yr 1. These constrains on the viscosity contrast can allow to discriminate between the LA coupling and decoupling. The growing seismic and mineralogical evidences of a possible ultra low viscosity asthenospheric layer may be indicative of the LA decoupling and their relative motions due to longwavelength perturbations, and a contribution of the tidal drag on the plate motion should not be neglected in the regions of high viscosity contrasts. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
Doglioni_etal_revision_included.doc | main article | 514 kB | Microsoft Word | |
figure.zip | Figure compressed format | 766.87 kB | winzip |
WEB OF SCIENCETM
Citations
20
37
checked on Feb 10, 2021
Page view(s) 50
397
checked on Apr 24, 2024
Download(s)
30
checked on Apr 24, 2024