Open AccessStress‐driven melt segregation in partially molten rocks
Author(s) -
Holtzman B. K.,
Groebner N. J.,
Zimmerman M. E.,
Ginsberg S. B.,
Kohlstedt D. L.
Publication year - 2003
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2001gc000258
Subject(s) - geology , anisotropy , permeability (electromagnetism) , simple shear , shear (geology) , compaction , mantle (geology) , mineralogy , deformation (meteorology) , petrology , geotechnical engineering , geophysics , oceanography , genetics , physics , quantum mechanics , membrane , biology
We demonstrate that deformation of partially molten ductile rocks can produce melt segregation by two‐phase flow. In simple shear experiments on several melt‐rock systems at high temperature and pressure, melt segregates into distinct melt‐rich layers oriented 20° to the shear plane. Melt segregates in samples in which pressure gradients can develop at length scales less than the sample thickness. A simple scaling argument combined with a comparison of length scale data suggests that such pressure gradients can develop in the samples with compaction lengths less than or on the order of the sample thickness. In nature, stress‐driven melt segregation may produce both high‐permeability pathways that contribute to rapid extraction of melt and localization of deformation that increases the anisotropy in viscosity of partially molten regions of the upper mantle and lower crust.