Melt-band instabilities with two-phase damage
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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
1365-246X
Volume Title
201
Publisher
Oxford University Press (OUP)
Publisher DOI
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.