Grain-scale melt distribution in two contact aureole rocks: implications for controls on melt localization and deformation

Shock Metamorphism in Impact Melt Rocks

Spontaneous Small-scale Melt Segregation in Partial Melts Undergoing Deformation

A partial melt undergoing large scale deformation is shown to be unstable with respect to small scale redistribution of melt, provided the shear viscosity of the matrix depends on melt fraction. In the physically realistic case where melt "softens" the matrix, melt migrates along the direction parallel to the axis of minimum compressive stress and accumulates in "veins" (melt-rich lenses). The ...

Contrasting viscoelastic behavior of melt-free and melt-bearing olivine: Implications for the nature of grain-boundary sliding

Melt-free and basaltic (complex alumino-silicate) melt-bearing specimens of fine-grained polycrystalline olivine (Mg0.9Fe0.1)2SiO4, tested at igh temperature and low frequency in torsional forced oscillation and microcreep, display markedly different behavior. For the melt-bearing aterials, superimposed upon the high-temperature background is a dissipation peak whose height varies systematicall...

Trapped Melt in the Josephine Peridotite: Implications for Permeability and Melt Extraction in the Upper Mantle

Tabular dunites in the Josephine peridotite of southwestern Oregon represent conduits for melt extraction from the upper mantle. The amount of melt trapped within these channels during cooling and exhumation of the peridotite massif was calculated using a mass-balance approach. These calculations suggest that no more than 0·1^0·2 vol. % melt could have been trapped within these dunites after cr...

Stress-driven melt segregation in partially molten rocks

[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 20 to the shear plane. Melt segregates in samples in which pressure gradients can develop at length scales less than the sample thic...