Some dynamical consequences of partial melting in Earth's deep mantle | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

Twitter

Aller au compte twitter

  Some dynamical consequences of partial melting in Earth's deep mantle

Type de publication:

Journal Article

Source:

Physics of the Earth and Planetary Interiors, Volume 162, Ticket 1-2, p.149-163 (2007)

ISBN:

0031-9201

URL:

http://www.sciencedirect.com/

Mots-clés:

FLOTATION

Résumé:

We use regional scale numerical models of mantle convection to investigate the simple hypothesis that seismically anomalous thin patches of Earth's lowermost mantle, termed "ultralow-velocity zones" or ULVZ, are derived from partial melting of ordinary mantle. The models span the lower 500 km of Earth's mantle, employ both temperature and melting-related contributions to buoyancy, and include a cold randomly moving downwelling introduced from above to maintain a thermal boundary layer. Partial melting of ordinary mantle introduces a ubiquitous partially molten layer above an isothermal core-mantle boundary as a consequence of its isothermal and isobaric conditions, although it naturally develops variations in thickness greater than two orders of magnitude, with the thickest portions occurring at the base of upwelling plumes and a thin layer elsewhere. We find that only a dense partially molten mixture produces partial melt distributions that are compatible with seismic observations of ULVZ; however, if such a melt percolates downward a dense basal liquid layer accumulates above the core-mantle boundary. The apparent requirement of a volumetrically dense and non-percolating melt phase in the lowermost mantle presents serious problems for the hypothesis that ULVZ arise from melting of ordinary mantle, and suggests that such features likely form as a consequence of more complex processes. Furthermore, these considerations suggest that the solidus of ordinary mantle is a reasonable upper bound on the present day temperature of the CMB. (c) 2007 Published by Elsevier B.V

Notes:

Phys. Earth Planet. Inter.ISI Document Delivery No.: 190LLTimes Cited: 0Cited Reference Count: 104Cited References:AGEE CB, 1988, J GEOPHYS RES, V93, P3437AGEE CB, 1993, EARTH PLANET SC LETT, V114, P315AGEE CB, 1998, PHYS EARTH PLANET IN, V107, P63AKINS JA, 2004, GEOPHYS RES LETT, V31, ARTN L14612AURNOU JM, 1996, GEOPHYS RES LETT, V23, P2705AVANTS M, 2006, GEOPHYS RES LETT, V33, ARTN L07314BERRYMAN JG, 2000, GEOPHYS RES LETT, V27, P421BOEHLER R, 2000, REV GEOPHYS, V38, P221BRAGINSKY SI, 1999, PHYS EARTH PLANET IN, V111, P21BRANDON AD, 2005, EARTH PLANET SC LETT, V232, P211, DOI10.1016/j.epsl.2005.01.034BRITO D, 1999, PHYS EARTH PLANET IN, V112, P159BUFFET BA, 1996, GEOPHYS RES LETT, V23, P3803BUFFETT BA, 2000, SCIENCE, V290, P1338CHRISTENSEN U, 1984, ANN GEOPHYS, V2, P311CHRISTENSEN UR, 1989, PHILOS T R SOC A, V328, P417CHRISTENSEN UR, 1994, J GEOPHYS RES-SOL EA, V99, P19867CLEMENT BM, 1991, EARTH PLANET SC LETT, V104, P48COLTICE N, 1999, EARTH PLANET SC LETT, V174, P125CORGNE A, 2002, GEOPHYS RES LETT, V29, ARTN 1933COSTIN SO, 2004, J GEOPHYS RES-SOL EA, V109, ARTN B06101DAVIES GF, 1986, GEOPHYS RES LETT, V13, P1517DOBSON DP, 2005, NATURE, V434, P371, DOI 10.1038/nature03385DUBROVINSKY L, 2001, NATURE, V412, P527DUBROVINSKY L, 2004, PHYS EARTH PLANET IN, V146, P243, DOI10.1016/j.pepi.2003.07.028DUFFY TS, 1992, HIGH PRESSURE RES AP, P197EATON DW, 2005, FARN EARTH PLANET IN, V155, P104FARNETANI CG, 1997, GEOPHYS RES LETT, V24, P1583GARNERO EJ, 1996, GEOPHYS RES LETT, V23, P977GARNERO EJ, 2000, GEOPHYS RES LETT, V27, P2777GARNERO EJ, 2004, SCIENCE, V306, P259GUBBINS D, 1998, AGU GEOPHYSICAL MONO, P167GURNIS M, 1986, J GEOPHYS RES-SOLID, V91, P11407HANSEN U, 1988, NATURE, V334, P237HELFFRICH G, 2004, SCIENCE, V306, P2239, DOI 10.1126/science.1101109HELMBERGER DV, 1998, NATURE, V396, P251HERNLUND JW, 2005, NATURE, V434, P882, DOI 10.1038/nature03472HERNLUND JW, 2006, DYNAMICS ASSOCIATEDHIROSE K, 2004, PHYS EARTH PLANET IN, V146, P249, DOI10.1016/j.pepi.2002.11.001JELLINEK AM, 2002, NATURE, V418, P760JELLINEK AM, 2004, REV GEOPHYS, V42, P3002KANDA RVS, 2006, GEOPHYS RES LETT, V33, ARTN L02310KELLOGG LH, 1993, GEOPHYS RES LETT, V20, P379KNITTLE E, 1991, SCIENCE, V251, P1438KNITTLE E, 1998, CORE MANTLE BOUNDARY, P119LABROSSE S, 1997, PHYS EARTH PLANET IN, V99, P1LAJ C, 1991, NATURE, V351, P447LAY T, 1990, GEOPHYS RES LETT, V17, P2001LAY T, 2004, PHYS EARTH PLANET IN, V146, P441, DOI10.1016/j.pepi.2004.04.004LAY T, 2006, SCIENCE, V314, P1272, DOI 10.1126/science.1133280LISTER JR, 1998, PHYS EARTH PLANET IN, V105, P5LIU L, 1986, ELEMENTS OXIDES SILILUO SN, 2001, EARTH PLANET SC LETT, V189, P155MANGA M, 1996, GEOPHYS RES LETT, V23, P3091MAO WL, 2006, SCIENCE, V312, P564, DOI 10.1126/science.1123442MATYSKA C, 1994, EARTH PLANET SC LETT, V125, P255MCNAMARA AK, 2004, J GEOPHYS RES-SOL EA, V109, ARTN B07402MCNAMARA AK, 2005, NATURE, V437, P1136, DOI 10.1038/nature04066MOORE WB, 1998, SCIENCE, V279, P1008MORGAN WJ, 1971, NATURE, V230, P42MORSE SA, 2001, AM MINERAL, V85, P387MURAKAMI M, 2004, SCIENCE, V304, P855, DOI 10.1126/science.1095932NAKAGAWA T, 2004, PHYS EARTH PLANET IN, V146, P125, DOI10.1016/j.pepi.2003.05.006OGANOV AR, 2004, NATURE, V430, P445, DOI 10.1038/nature02701OHTANI E, 1993, P JPN ACAD B-PHYS, V69, P23OHTANI E, 2001, EARTH PLANET SC LETT, V193, P69OKAMOTO T, 2005, PHYS EARTH PLANET IN, V153, P32, DOI10.1016/j.pepi.2005.03.018OLSON P, 1987, NATURE, V327, P409OLSON P, 1991, J GEOPHYS RES-SOLID, V96, P4347PERSH SE, 2001, GEOPHYS RES LETT, V28, P859PETFORD N, 2005, EARTH PLANETS SPACE, V57, P459POIRIER JP, 1998, CORE MANTLE BOUNDARY, P131REASONER C, 2000, J GEOPHYS RES B, V105, P173REVENAUGH J, 1997, SCIENCE, V277, P670RIGDEN SM, 1984, SCIENCE, V226, P1071ROMANOWICZ B, 2002, SCIENCE, V296, P513RONDENAY S, 2003, J GEOPHYS RES-SOL EA, V108, ARTN 2537ROSS AR, 2004, J GEOPHYS RES-SOL EA, V109, ARTN B08303ROST S, 2003, J GEOPHYS RES-SOL EA, V108, ARTN 2056ROST S, 2005, NATURE, V435, P666, DOI 10.1038/nature03620RUNCORN SK, 1992, NATURE, V356, P654SAKAMAKI T, 2006, NATURE, V439, P192, DOI 10.1038/nature04352SCHUBERT G, 2004, PHYS EARTH PLANET IN, V146, P147, DOI10.1016/j.pepi.2003.09.025SLEEP NH, 1988, GEOPHYS J, V95, P437STEINBACH V, 1999, EARTH PLANET SC LETT, V172, P213STIXRUDE L, 2005, SCIENCE, V310, P297, DOI 10.1126/science.1116952SUZUKI A, 1995, SCIENCE, V269, P216SUZUKI A, 2003, PHYS CHEM MINER, V30, P449, DOI10.1007/s00269-003-0322-6TACKLEY PJ, 1996, J GEOPHYS RES-SOL EA, V101, P3311TACKLEY PJ, 1998, CORE MANTLE BOUNDARY, P231TACKLEY PJ, 2002, GEOCHEM GEOPHY GEOSY, P3THORNE MS, 2004, J GEOPHYS RES-SOL EA, V109, ARTN B08301THORNE MS, 2004, PHYS EARTH PLANET IN, V146, P47, DOI10.1016/j.pepi.2003.09.026TORSVIK TH, 2006, GEOPHYS J INT, V167, P1447, DOI10.1111/j.1365-246X.2006.03158.xTRAMPERT J, 2004, SCIENCE, V306, P853TSUCHIYA T, 2004, EARTH PLANET SC LETT, V224, P241VALET JP, 1992, NATURE, V356, P400VANDERHILST RD, 2007, SCIENCE, V30, P1813WALKER D, 2002, GEOCHEM GEOPHY GEOSY, V3, ARTN 1070WEN LX, 2001, EARTH PLANET SC LETT, V194, P83WILLIAMS Q, 1996, SCIENCE, V273, P1528WILLIAMS Q, 1998, SCIENCE, V281, P546XIE SX, 2004, J GEOPHYS RES-SOL EA, V109, ARTN B11204XIE SX, 2004, PHYS EARTH PLANET IN, V146, P417, DOI10.1016/j.pepi.2004.04.003YAMAZAKI D, 2001, AM MINERAL, V86, P385