The orientation of melt bands in an extending lithosphere

Muhlhaus, Hans, Mohajeri, Arash, Finzi, Yaron and Regenauer-Lieb, Klaus (2012). The orientation of melt bands in an extending lithosphere. In: J. Eberhardsteiner, 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012), Vienna, Austria, (7344-7356). 10-14 September 2012.

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Author Muhlhaus, Hans
Mohajeri, Arash
Finzi, Yaron
Regenauer-Lieb, Klaus
Title of paper The orientation of melt bands in an extending lithosphere
Conference name 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012)
Conference location Vienna, Austria
Conference dates 10-14 September 2012
Journal name ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers
Place of Publication Vienna, Austria
Publisher Vienna University of Technology
Publication Year 2012
Sub-type Fully published paper
ISBN 9783950353709
9783950248197
Editor J. Eberhardsteiner
Start page 7344
End page 7356
Total pages 13
Collection year 2013
Language eng
Abstract/Summary Understanding how melt flow is organized on lithospheric scales is an important goal in modelling magma dynamics and tectonic processes such as rifting. Observations from nature and experimental data indicate that strain is highly localised in crustal and mantle shear zones and that melt processes may further enhance strain-localization of these structures. The coupling of lithospheric shear zones and melt flow is a key aspect in these processes and an outstanding challenge for both numerical modellers and geologists in recent years. We present an outline of the equations governing melting and melt solid interactions. A simple model for mass transfer during melting is proposed. In our model the temperature is eliminated as an independent variable by taking advantage of the fact that the Peclet number (characteristic spreading time/thermal diffusion time) is expected to be large beneath spreading centers. We present a linear instability analysis of localization in pure-shear which is tailored to represent deformation of a partly molten lithosphere in extension. Our analysis outlines two deformational regimes: melt-band dominated and shear-band dominated deformation. The nonlinear regime is explored in fully coupled finite element studies. The numerical analyses confirm the orientations of the localizations predicted in the linear instability analysis whereby the strength of the localization increases with increasing power law coefficient of the strain rate dependent viscosity. The influence of active melting turns out to be negligible for the order of strain rates considered here.
Keyword Melt segregation
Linear instability
Numerical simulation
Q-Index Code EX
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Conference Paper
Collections: School of Earth Sciences Publications
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Created: Mon, 14 Jan 2013, 11:46:17 EST by Hans-Bernd Muhlhaus on behalf of School of Earth Sciences