Magmatic channelization by reactive and shear-driven instabilities at mid-ocean ridges: a combined analysis
نویسندگان
چکیده
It is generally accepted that melt extraction from the mantle at mid-ocean ridges (MORs) concentrated in narrow regions of elevated fraction called channels. Two feedback mechanisms have been proposed to explain why these channels grow by linear instability: shear flow partially molten and reactive ascending magma. These two studied extensively, isolation each other, through theory laboratory experiments as well field geophysical observations. Here, we develop a consistent accounts for both allows us weigh their relative contributions. We show interaction insignificant total growth rate well-approximated summing independent rates. Furthermore, how competition governed orientation with respect gravity shear. By itself, analysis reaction-infiltration instability predicts formation tube-shaped addition even small amount extension horizontal, combined favours tabular channels, observed morphology dunite bodies ophiolites. apply new MORs calculating accumulated rotation along streamlines solid flow. dominant mechanism deep beneath ridge axis, where most unstable high-porosity sub-vertical. Channels are then rotated away vertical. The contribution shear-driven confined margins melting region. Within limitations our study, not responsible significant focusing or shallowly dipping seismic anisotropy [abridged].
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 2021
ISSN: ['1365-246X', '0956-540X']
DOI: https://doi.org/10.1093/gji/ggab112