Stress-driven melt segregation in partially molten rocks

Publication Type  Journal Article
Year of Publication  2003
Authors  Holtzman, B. K.; Groebner, N. J.; Zimmerman, M. E.; Ginsberg, S. B.; Kohlstedt, D. L.
Journal Title  Geochemistry Geophysics Geosystems
Volume  4
Pages  -
Journal Date  May 9
ISBN Number  1525-2027
Accession Number  ISI:000182872500001
Key Words  melt segregation; deformation partially molten rocks; channel formation; mantle transport properties; mantle rheology; mantle seismic properties; marine geology and geophysics : midocean ridge processes; mineral physics : creep and deformation; physical p

[1] 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 20degrees 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.


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URL  <Go to ISI>://000182872500001
DOI  Doi 10.1029/2001gc000258