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Melt-band instabilities with two-phase damage


Type

Article

Change log

Authors

Rudge, JF 
Bercovici, D 

Abstract

Deformation experiments on partially molten rocks in simple shear form melt bands at 20◦ to the shear plane instead of at the expected 45◦ principal compressive stress direction. Thesemelt bands may play an important role in melt focusing in mid-ocean ridges. Such shallow bands are known to form for two-phase media under shear if strongly non-Newtonian power-law creep is employed for the solid phase, or anisotropy imposed. However laboratory experiments show that shallow bands occur regardless of creep mechanism, even in diffusion creep, which is nominally Newtonian. Here we propose that a couple of forms of two-phase damage allow for shallow melt bands even in diffusion creep.

Description

Keywords

Creep and deformation, Mid-ocean ridge processes, Mechanics, theory, and modelling, Rheology: mantle, Magma migration and fragmentation

Journal Title

Geophysical Journal International

Conference Name

Journal ISSN

0956-540X
1365-246X

Volume Title

201

Publisher

Oxford University Press (OUP)
Sponsorship
Natural Environment Research Council (NE/I023929/1)
Support was provided by the National Science Foundation (NSF, grant EAR-1015229), the Natural Environment Research Council (NERC, grant NE/I023929/1) and Trinity College.