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Spontaneous small-scale melt segregation in partial melts undergoing deformation

Stevenson, David J. (1989) Spontaneous small-scale melt segregation in partial melts undergoing deformation. Geophysical Research Letters, 16 (9). pp. 1067-1070. ISSN 0094-8276. http://resolver.caltech.edu/CaltechAUTHORS:20140414-090819260

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Abstract

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 maximum growth rate of the instability is of order —⋵_od ln η/df (⋵_o ≡ largest component of the principal strain tensor, η = shear viscosity, f = melt fraction), and plausibly fast enough to invalidate the conventional applications of Darcy's law (e.g., mid-ocean ridges, subduction zones) since melt migrates into veins in preference to being pervasively flushed vertically. The preferred lengthscale of the instability is poorly determined but probably ∼ meters. Veins may eventually form an interconnected drainage network, allowing rapid vertical flushing of melt.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://onlinelibrary.wiley.com/doi/10.1029/GL016i009p01067/abstractPublisherArticle
http://dx.doi.org/10.1029/GL016i009p01067DOIArticle
ORCID:
AuthorORCID
Stevenson, David J.0000-0001-9432-7159
Additional Information:© 1989 American Geophysical Union. Paper number 89GL01416. Manuscript Accepted: 5 Jul 1989. Manuscript Received: 2 Jun 1989. Comments from N. Sleep and an anonymous reviewer were helpful. This work is supported by NSF Earth Sciences grants EAR8618511 and EAR8816268. Contribution number 4764 from the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125.
Funders:
Funding AgencyGrant Number
NSFEAR-8618511
NSFEAR-8816268
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Caltech Division of Geological and Planetary Sciences4764
Record Number:CaltechAUTHORS:20140414-090819260
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140414-090819260
Official Citation:Spontaneous small-scale melt segregation in partial melts undergoing deformation (pages 1067–1070) David J. Stevenson DOI: 10.1029/GL016i009p01067
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44910
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:14 Apr 2014 16:27
Last Modified:24 Nov 2015 01:32

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