Asimow, Paul D. and Stolper, E. M.
Steady-state Mantle–Melt Interactions in One Dimension: I. Equilibrium Transport and Melt Focusing.
Journal of Petrology, 40
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Mantle–melt interaction during melt transport is explored in one dimension and steady state. We reconsider the equivalence between one-dimensional steady equilibrium transport and batch melting. In the absence of diffusion and radioactivity, conservation of mass flux requires that the major and trace element compositions of melt and solid at each point are the same as is generated by batch melting the source composition at the same pressure and temperature. Energy conservation requires that temperature and extent of melting are independent of melt migration except for irreversible source terms related to viscous compaction and gravitational energy release. The equivalence of phase compositions at each pressure between steady-state equilibrium transport and batch melting simplifies melt transport calculations. We examine the effects of increasing the melt flux to simulate melt focusing by channeling or by two-dimensional flow with converging melt streamlines. Melt focusing modifies the mineralogy of both residual matrix and erupted melt. We use MELTS calculations to model the formation of dunite by this mechanism and quantify the melt flux required to exhaust orthopyroxene from the residue as a function of pressure. The model dunites are found to be similar to natural dunites observed in the mantle section of ophiolite sequences.
|Additional Information:||© 1999 Oxford University Press.
Received December 1, 1997; accepted August 13, 1998.
The authors thank Tim Elliott, Peter Reiners and Marc Spiegelman for careful and thoughtful reviews, and Jon Davidson for editorial handling. John Longhi kindly performed some calculations for us with his melting model. We have had numerous helpful discussions with Peter Kelemen and Marc Spiegelman. This work was supported by NSF Grants OCE-9529878 and EAR 9219899, and by a Lamont–Doherty Earth Observatory postdoctoral fellowship to P.D.A. This is Caltech Division of Geological and Planetary Sciences Contribution 8508.|
|Funding Agency||Grant Number|
|Lamont–Doherty Earth Observatory (LDEO)||UNSPECIFIED|
|Subject Keywords:||dunite; magma migration; porous flow; mid-ocean ridge processes
|Other Numbering System:|
|Other Numbering System Name||Other Numbering System ID|
|Caltech Division of Geological and Planetary Sciences||8508|
|Official Citation:||P. D. Asimow and E. M. Stolper
Steady-state Mantle–Melt Interactions in One Dimension: I. Equilibrium Transport and Melt Focusing J. Petrology (1999) 40(3): 475-494 doi:10.1093/petroj/40.3.475|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited On:||21 Aug 2012 22:53|
|Last Modified:||09 Dec 2016 17:31|
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