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Steady-state Mantle–Melt Interactions in One Dimension: II. Thermal Interactions and Irreversible Terms

Asimow, Paul D. (2002) Steady-state Mantle–Melt Interactions in One Dimension: II. Thermal Interactions and Irreversible Terms. Journal of Petrology, 43 (9). pp. 1707-1724. ISSN 0022-3530. https://resolver.caltech.edu/CaltechAUTHORS:ASIjpet02

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Abstract

Progress in development of thermodynamically based models of silicate equilibria with explicit entropy budgets has motivated a reexamination of the conclusion of McKenzie (Journal of Petrology 25, 713–765, 1984) that isentropic upwelling suffices as a model of mantle melting. An entropy budget equation for fractional melting with melt migration in an upwelling two-phase continuum is presented. The energetically self-consistent melt production model predicted by MELTS is used to evaluate numerically the magnitudes of differences between fractional melting (with melt migration) and equilibrium melting (without relative movement) that can be bounded in one dimension: chemical advection by out-of-equilibrium melt; thermal disequilibrium between migrating liquid and residue; frictional dissipation of gravitational potential; dissipation as a result of solid compaction. Like the familiar isobaric case in which fractional melting is significantly less productive than equilibrium melting, chemical isolation of the escaping melts from the residue reduces the oceanic crustal thickness by ~1 km. Allowing escaping melts to move on their own adiabats and ascend at higher temperature than the residue further suppresses melting but yields only ~100 m less crustal thickness. Extra crustal thickness as a result of gravitational dissipation is ~100 m, much smaller than the effect of chemical isolation. Viscous dissipation as a result of compaction is negligible.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/petrology/43.9.1707DOIUNSPECIFIED
ORCID:
AuthorORCID
Asimow, Paul D.0000-0001-6025-8925
Additional Information:© Oxford University Press 2002. Reprinted with permission. Received August 2, 2001; Revised typescript accepted March 26, 2002 The author wishes most of all to thank Ed Stolper for his unselfish support throughout this project. Thanks also go to Frank Spera and an anonymous reviewer for helpful reviews, and to George Bergantz for editorial handling. Discussions with Marc Spiegelman and Dan McKenzie helped refine my understanding of dissipation. This work was supported by NSF grants OCE-9529878 and EAR-9219899 and by a Lamont–Doherty Earth Observatory postdoctoral fellowship. This is Caltech Division of Geological and Planetary Sciences Contribution 8801.
Subject Keywords:isentropic melting; melt migration; dissipation; porous flow; mantle adiabat
Issue or Number:9
Record Number:CaltechAUTHORS:ASIjpet02
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:ASIjpet02
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1462
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:19 Jan 2006
Last Modified:02 Oct 2019 22:43

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