Water and fabric in an ophiolitic peridotite from a supra-subduction zone

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• 作者：Yongfeng Wang ; Huaping Ren ; Zhenmin Jin
• 关键词：Water ; Supra ; subduction zone ; Ophiolite ; Peridotite ; CPO ; Tibet
• 刊名：Contributions to Mineralogy and Petrology
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：171
• 期：3
• 全文大小：1,966 KB
• 参考文献：Arai S (1992) Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistry. Mineral Mag 56:173–184CrossRef
  Arai S (1994) Characterization of spinel peridotites by olivine-spinel compositional relationships: review and interpretation. Chem Geol 113:191–204CrossRef
  Arai S, Ishimaru S (2008) Insights into petrological characteristics of the lithosphere of mantle wedge beneath arcs through peridotite xenoliths: a review. J Petrol 49:665–695CrossRef
  Aubaud C, Hauri EH, Hirschmann MM (2004) Hydrogen partition coefficients between nominally anhydrous minerals and basaltic melts. Geophys Res Lett 31:L20611. doi:10.​1029/​22004GL021341 CrossRef
  Ballhaus C, Berry RF, Green DH (1991) High pressure experimental calibration of the olivine-orthopyroxene-spinel oxygen geobarometer: implications for the oxidation state of the upper mantle. Contrib Mineral Petrol 107:27–40CrossRef
  Barth MG, Mason PRD, Davies GR, Dijkstra AH, Drury MR (2003) Geochemistry of the Othris ophiolite, Greece: evidence for refertilization? J Petrol 44:1759–1785CrossRef
  Bazylev BA, Karamata S, Zakariadze GS (2003) Petrology and evolution of the Brezovica ultramafic massif, Serbia. In: Dilek Y, Robinson PT (eds) Ophiolites in Earth history, vol 218. Geol Soc Spec Pub, London, pp 91–108
  Bell DR, Rossman GR (1992) Water in the earth’s mantle: the role of nominally anhydrous minerals. Science 255:1391–1397CrossRef
  Bell DR, Ihinger PD, Rossman GR (1995) Quantitative analysis of trace OH in garnet and pyroxenes. Am Mineral 80:465–474CrossRef
  Ben Ismaïl W, Mainprice D (1998) An olivine fabric database: an overview of upper mantle fabrics and seismic anisotropy. Tectonophysics 296:145–157CrossRef
  Bezard R, Hébert R, Wang C, Dostal J, Dai J, Zhong H (2011) Petrology and geochemistry of the Xiugugabu ophiolitic massif, western Yarlung Zangbo suture zone, Tibet. Lithos 125:347–367CrossRef
  Bizimis M, Peslier AH (2015) Water in Hawaiian garnet pyroxenites: implications for water heterogeneity in the mantle. Chem Geol 397:61–75CrossRef
  Bonadiman C, Hao Y, Coltorti M, Dallai L, Faccini B, Huang Y, Xia Q (2009) Water contents of pyroxenes in intraplate lithospheric mantle. Eur J Mineral 21:637–647CrossRef
  Bonatti E, Michael PJ (1989) Mantle peridotites from continental rifts to ocean basins to subduction zones. Earth Planet Sci Lett 91:297–311CrossRef
  Brey GP, Köhler T (1990) Geothermobarometry in four-phase lherzolites II. New thermobarometers, and practical assessment of existing thermobarometers. J Petrol 31:1353–1378CrossRef
  Chen S, Hiraga T, Kohlstedt DL (2006) Water weakening of clinopyroxene in the dislocation creep regime. J Geophys Res 111:B08203
  Christensen NI, Lundquist SM (1982) Pyroxene orientation within the upper mantle. Geol Soc Am Bull 93:279–288CrossRef
  Costa F, Chakraborty S (2008) The effect of water on Si and O diffusion rates in olivine and implications for transport properties and processes in the upper mantle. Phys Earth Planet Inter 166:11–29CrossRef
  Dai JG, Wang CS, Hébert R, Santosh M, Li YL, Xu JY (2011) Petrology and geochemistry of peridotites in the Zhongba ophiolite, Yarlung Zangbo Suture Zone: implications for the Early Cretaceous intra-oceanic subduction zone within the Neo-Tethys. Chem Geol 288:133–148CrossRef
  Demouchy S, Mackwell S (2006) Mechanisms of hydrogen incorporation and diffusion in iron-bearing olivine. Phys Chem Miner 33:347–355CrossRef
  Demouchy S, Jacobsen SD, Gaillard F, Stern CR (2006) Rapid magma ascent recorded by water diffusion profiles in mantle olivine. Geology 34:429–432CrossRef
  Demouchy S, Ishikawa A, Tommasi A, Alard O, Keshav S (2015) Characterization of hydration in the mantle lithosphere: peridotite xenoliths from the Ontong Java Plateau as an example. Lithos 212–215:189–201CrossRef
  Denis C, Demouchy S, Shaw CSJ (2013) Evidence of dehydration in peridotites from Eifel Volcanic Field and estimates of magma ascent rates. J Volcanol Geotherm Res 258:85–99CrossRef
  Denis C, Alard O, Demouchy S (2015) Water content and hydrogen behavior during metasomatism in the uppermost mantle beneath Ray Pic volcano (Massif Central, France). Lithos 236–237:256–274CrossRef
  Dick HJB, Bullen T (1984) Chromian spinal as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. Contrib Mineral Petrol 86:54–76CrossRef
  Dijkstra AH, Drury MR, Frijhoff RM (2002) Microstructures and lattice fabrics in the Hilti mantle section (Oman Ophiolite): evidence for shear localization and melt weakening in the crust–mantle transition zone? J Geophys Res 107:2270. doi:10.​1029/​2001JB000458 CrossRef
  Doucet LS, Peslier AH, Ionov DA, Brandon AD, Golovin AV, Goncharov AG, Ashchepkov IV (2014) High water contents in the Siberian cratonic mantle linked to metasomatism: an FTIR study of Udachnaya peridotite xenoliths. Geochim Cosmochim Acta 137:159–187CrossRef
  Drury MR, Avé Lallemant HG, Pennock GM, Palasse LN (2011) Crystal preferred orientation in peridotite ultramylonites deformed by grain size sensitive creep, Étang de Lers, Pyrenees, France. J Struct Geol 33:1776–1789CrossRef
  Férot A, Bolfan-Casanova N (2012) Water storage capacity in olivine and pyroxene to 14 GPa: implications for the water content of the Earth’s upper mantle and nature of seismic discontinuities. Earth Planet Sci Lett 349–350:218–230CrossRef
  Girardeau J, Marcoux J, Allègre CJ, Bassouliet JP, Tang Y, Xiao X, Zao Y, Wang X (1984) Tectonic environment and geodynamic significance of the Neo-Cimmerian Donqiao ophiolite, Bangong-Nujiang suture zone, Tibet. Nature 307:27–31CrossRef
  Girardeau J, Mercier JCC, Tang Y (1986) Petrology of the Donqiao-Xainxa ophiolite (north Tibet, China): evidence for its formation in a supra-subduction zone environment. Ofioliti 11:235–262
  Gose J, Schmädicke E, Beran A (2009) Water in enstatite from Mid-Atlantic Ridge peridotite: Evidence for the water content of suboceanic mantle? Geology 37:543–546CrossRef
  Gose J, Schmädicke E, Stalder R (2011) Water in mantle orthopyroxene-no visible change in defect water during serpentinization. Eur J Mineral 23:529–536CrossRef
  Grant K, Ingrin J, Lorand JP, Dumas P (2007) Water partitioning between mantle minerals from peridotite xenoliths. Contrib Mineral Petrol 154:15–34CrossRef
  Grove TL, Chatterjee N, Parman SW, Médard E (2006) The influence of H2O on mantle wedge melting. Earth Planet Sci Lett 249:74–89CrossRef
  Hao Y, Xia Q, Li Q, Chen H, Feng M (2014) Partial melting control of water contents in the Cenozoic lithospheric mantle of the Cathaysia block of South China. Chem Geol 380:7–19CrossRef
  Hirth G, Kohlstedt DL (1996) Water in the oceanic upper mantle: implications for rheology, melt extraction and the evolution of the lithosphere. Earth Planet Sci Lett 144:93–108CrossRef
  Ingrin J, Blanchard M (2006) Diffusion of hydrogen in mantle minerals. Rev Mineral Geochem 62:291–320CrossRef
  Ingrin J, Skogby H (2000) Hydrogen in nominally anhydrous upper-mantle minerals: concentration levels and implications. Eur J Mineral 12:543–570CrossRef
  Jaques AL, Green DH (1980) Anhydrous melting of peridotite at 0–15 kb pressure and the genesis of tholeiitic basalts. Contrib Mineral Petrol 73:287–310CrossRef
  Jung H, Karato S (2001a) Water-induced fabric transitions in olivine. Science 293:1460–1463CrossRef
  Jung H, Karato S (2001b) Effects of water on dynamically recrystallized grain-size of olivine. J Struct Geol 23:1337–1344CrossRef
  Jung H, Katayama I, Jiang Z, Hiraga T, Karato S (2006) Effect of water and stress on the lattice-preferred orientation of olivine. Tectonophysics 421:1–22CrossRef
  Kaczmarek MA, Jonda L, Davies HL (2015) Evidence of melting, melt percolation and deformation in a supra-subduction zone (Marum ophiolite complex, Papua New Guinea). Contrib Mineral Petrol 170:19. doi:10.​1007/​s00410-015-1174-z CrossRef
  Khedr MZ, Arai S, Python M, Tamura A (2014) Chemical variations of abyssal peridotites in the central Oman ophiolite: evidence of oceanic mantle heterogeneity. Gondwana Res 25:1242–1262CrossRef
  Kohlstedt DL, Keppler H, Rubie DC (1996) Solubility of water in the α-phase, β-phase and γ-phase of (MgFe)2SiO4. Contrib Mineral Petrol 123:345–357CrossRef
  Kovács I, Hermann J, O’Neill HSC, Gerald FJ, Sambridge M, Horváth G (2008) Quantitative absorbance spectroscopy with unpolarized light: Part II. Experimental evaluation and development of a protocol for quantitative analysis of mineral IR spectra. Am Mineral 93:765–778CrossRef
  Le Roux V, Tommasi A, Vauchez A (2008) Feedback between melt percolation and deformation in an exhumed lithosphere-asthenosphere boundary. Earth Planet Sci Lett 274:401–413CrossRef
  Li ZXA, Lee CTA, Peslier AH, Lenardic A, Mackwell SJ (2008) Water contents in mantle xenoliths from the Colorado Plateau and vicinity: implications for the mantle rheology and hydration-induced thinning of continental lithosphere. J Geophys Res 113:B09210. doi:10.​1029/​2007JB005540
  Litasov K, Taniguchi H (2008) Hydrogen contents of mantle minerals from peridotite xenoliths of Ichinomegata Volcano, NE Japan. Northeast Asian Stud 12:119–132
  Liu T (2014) Petrological, geochemical and geochronological characteristics of the Dongqiao ophiolite, Tibet and its tectonic evolution. Dissertation, China University of Geosciences (Beijing) (in Chinese)
  Mainprice D, Tommasi A, Couvy H, Cordier P, Frost DJ (2005) Pressure sensitivity of olivine slip systems: implications for the interpretation of seismic anisotropy of the Earth’s upper mantle. Nature 433:731–733CrossRef
  Mei S, Kohlstedt DL (2000) Influence of water on plastic deformation of olivine aggregates 2. Dislocation creep regime. J Geophys Res 105:21471–21481CrossRef
  Michibayashi K, Mainprice D (2004) The role of pre-existing mechanical anisotropy on shear zone development within oceanic mantle lithosphere: an example from the Oman ophiolite. J Petrol 45:405–414CrossRef
  Michibayashi K, Oohara T (2013) Olivine fabric evolution in a hydrated ductile shear zone at the Moho Transition Zone, Oman Ophiolite. Earth Planet Sci Lett 377–378:299–310CrossRef
  Mierdel K, Keppler H (2004) The temperature dependence of water solubility in enstatite. Contrib Mineral Petrol 148:305–311CrossRef
  Mierdel K, Keppler H, Smyth JR, Langenhorst F (2007) Water solubility in aluminous orthopyroxene and the origin of Earth’s asthenosphere. Science 315:364–368CrossRef
  Mosenfelder JL, Rossman GR (2013) Analysis of hydrogen and fluorine in pyroxenes: I. Orthopyroxene. Am Mineral 98:1026–1041CrossRef
  Mosenfelder JL, Deligne NI, Asimow PD, Rossman GR (2006) Hydrogen incorporation in olivine from 2–12 GPa. Am Mineral 91:285–294CrossRef
  Nakajima J, Hasegawa A (2004) Shear-wave polarization anisotropy and subduction-induced flow in the mantle wedge of northeastern Japan. Earth Planet Sci Lett 225:365–377CrossRef
  Nicolas A, Boudier F, Bouchez JL (1980) Interpretation of peridotite structures from ophiolitic and oceanic environments. Am J Sci 280A:192–210
  Nimis P, Grütter H (2010) Internally consistent geothermometers for garnet peridotites and pyroxenites. Contrib Mineral Petrol 159:411–427CrossRef
  Nimis P, Taylor WR (2000) Single clinopyroxene thermobarometry for garnet peridotites. Part I. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer. Contrib Mineral Petrol 139:541–554CrossRef
  Niu Y (1997) Mantle melting and melt extraction processes beneath ocean ridges: evidence from abyssal peridotites. J Petrol 38:1047–1074CrossRef
  Niu Y (2004) Bulk-rock major and trace element compositions of abyssal peridotites: implications for mantle melting, melt extraction and post-melting processes beneath Mid-Ocean Ridges. J Petrol 45:2423–2458CrossRef
  Ohuchi T, Irifune T (2013) Development of A-type olivine fabric in water-rich deep upper mantle. Earth Planet Sci Lett 362:20–30CrossRef
  Ohuchi T, Kawazoe T, Nishihara Y, Irifune T (2012) Change of olivine a-axis alignment induced by water: origin of seismic anisotropy in subduction zones. Earth Planet Sci Lett 317–318:111–119CrossRef
  Parkinson IJ, Pearce JA (1998) Peridotites from the Izu–Bonin–Mariana forearc (ODP Leg 125): evidence for mantle melting and melt–mantle interaction in a supra-subduction zone setting. J Petrol 39:1577–1618CrossRef
  Paterson M (1982) The determination of hydroxyl by infrared absorption in quartz, slilicate glasses and similar materials. Bull Mineral 105:20–29
  Paulick H, Bach W, Godard M, De Hoog JCM, Suhr G, Harvey J (2006) Geochemistry of abyssal peridotites (Mid-Atlantic Ridge, 15°20′N, ODP Leg 209): implications for fluid/rock interaction in slow spreading environments. Chem Geol 234:179–210CrossRef
  Pearce JA (2003) Supra-subduction zone ophiolites: the search for modern analogues. Geol Soc Am 373:269–293
  Pearce JA, Barker PF, Edwards SJ, Parkinson IJ, Leat PT (2000) Geochemistry and tectonic significance of peridotites from the South Sandwich arc-basin system, South Atlantic. Contrib Mineral Petrol 139:36–53CrossRef
  Peslier AH (2010) A review of water contents of nominally anhydrous natural minerals in the mantles of Earth, Mars and the Moon. J Volcanol Geotherm Res 197:239–258CrossRef
  Peslier AH, Luhr JF (2006) Hydrogen loss from olivines in mantle xenoliths from Simcoe (USA) and Mexico: mafic alkalic magma ascent rates and water budget of the sub-continental lithosphere. Earth Planet Sci Lett 242:302–319CrossRef
  Peslier AH, Luhr JF, Post J (2002) Low water contents in pyroxenes from spinel-peridotites of the oxidized, sub-arc mantle wedge. Earth Planet Sci Lett 201:69–86CrossRef
  Peslier AH, Snow JE, Hellebrand E, Von der Handt A (2007) Low water contents in minerals from Gakkel ridge abyssal peridotites, Arctic Ocean. Goldschmidt conference, pp A779
  Peslier AH, Woodland AB, Wolff JA (2008) Fast kimberlite ascent rates estimated from hydrogen diffusion profiles in xenolithic mantle olivines from southern Africa. Geochim Cosmochim Acta 72:2711–2722CrossRef
  Peslier AH, Woodland AB, Bell DR, Lazarov M (2010) Olivine water contents in the continental lithosphere and the longevity of cratons. Nature 467:78–81CrossRef
  Peslier AH, Woodland AB, Bell DR, Lazarov M, Lapen TJ (2012) Metasomatic control of water contents in the Kaapvaal cratonic mantle. Geochim Cosmochim Acta 97:213–246CrossRef
  Peslier AH, Bizimis M, Matney M (2015) Water disequilibrium in olivines from Hawaiian peridotites: recent metasomatism, H diffusion and magma ascent rates. Geochim Cosmochim Acta 154:98–117CrossRef
  Piccardo GB, Vissers RLM (2007) The pre-oceanic evolution of the Erro-Tobbio peridotite (Voltri Massif-Ligurian Alps, Italy). J Geodyn 43:417–449CrossRef
  Prechtel F, Stalder R (2012) OH-defects in Al- and Cr- doped synthetic enstatites and defect geobarometry on natural orthopyroxenes from the Earth’s mantle. Eur J Mineral 24:471–481CrossRef
  Rampone E, Hofmann AW, Piccardo GB, Vannucci R, Bottazzi P, Ottolini L (1996) Trace element and isotope geochemistry of depleted peridotites from an N-MORB type ophiolite (Internal Liguride, N. Italy). Contrib Mineral Petrol 123:61–76CrossRef
  Rampone E, Piccardo GB, Hofmann AW (2008) Multi-stage melt-rock interaction in the Mt. Maggiore (Corsica, France) ophiolitic peridotites: microstructural and geochemical evidence. Contrib Mineral Petrol 156:453–475CrossRef
  Rauch M, Keppler H (2002) Water solubility in orthopyroxene. Contrib Mineral Petrol 143:525–536CrossRef
  Robinson PT, Zhou MF (2008) The origin and tectonic setting of ophiolites in China. J Asian Earth Sci 32:301–307CrossRef
  Ross JV, Mercier JCC, Xu Y (1996) Diffusion creep in the upper mantle: an example from the Tanlu Fault, northeastern China. Tectonophysics 261:315–329CrossRef
  Sambridge M, Gerald JF, Kovács I, O’Neill HSC, Hermann J (2008) Quantitative absorbance spectroscopy with unpolarized light: Part I. Physical and mathematical development. Am Mineral 93:751–764CrossRef
  Schmädicke E, Gose J, Will TM (2011) Heterogeneous mantle underneath the North Atlantic: evidence from water in orthopyroxene, mineral composition and equilibrium conditions of spinel peridotite from different locations at the Mid-Atlantic Ridge. Lithos 125:308–320CrossRef
  Shi R, Griffin WL, O’Reilly SY, Huang Q, Zhang X, Liu D, Zhi X, Xia Q, Ding L (2012) Melt/mantle mixing produces podiform chromite deposits in ophiolites: implications of Re–Os systematics in the Dongqiao Neo-tethyan ophiolite, northern Tibet. Gondwana Res 21:194–206CrossRef
  Singh AK (2013) Petrology and geochemistry of abyssal peridotites from the Manipur ophiolite complex, Indo-Myanmar orogenic belt, Northeast India: implication for melt generation in mid-oceanic ridge environment. J Asian Earth Sci 66:258–276CrossRef
  Skemer P, Karato SI (2008) Sheared lherzolite xenoliths revisited. J Geophys Res 113:B07205CrossRef
  Skemer P, Warren JM, Kelemen PB, Hirth G (2010) Microstructural and rheological evolution of a mantle shear zone. J Petrol 51:43–53CrossRef
  Skemer P, Warren JM, Hansen LN, Hirth G, Kelemen PB (2013) The influence of water and LPO on the initiation and evolution of mantle shear zones. Earth Planet Sci Lett 375:222–233CrossRef
  Skogby H (2006) Water in natural mantle minerals I: pyroxenes. Rev Mineral Geochem 62:155–167CrossRef
  Soustelle V, Tommasi A, Demouchy S, Ionov DA (2010) Deformation and fluid–rock interaction in the supra-subduction mantle: microstructures and water contents in peridotite xenoliths from the Avacha Volcano, Kamchatka. J Petrol 51:363–394CrossRef
  Soustelle V, Tommasi A, Demouchy S, Franz L (2013) Melt–rock interactions, deformation, hydration and seismic properties in the sub-arc lithospheric mantle inferred from xenoliths from seamounts near Lihir, Papua New Guinea. Tectonophysics 608:330–345CrossRef
  Suhr G (1993) Evaluation of upper mantle microstructures in the Table Mountain massif (Bay of Islands ophiolite). J Struct Geol 15:1273–1292CrossRef
  Sun S, McDonough WF (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: Saunders AD, Norry MJ (eds) Magmatism in the ocean basins, vol 42. Geol Soc Spec Pub, London, pp 313–345
  Taylor WR (1998) An experimental test of some geothermometer and geobarometer formulations for upper mantle peridotites with application to the thermobarometry of fertile lherzolite and garnet websterite. Neues Jahrb Geol Palaontol Abh 172:381–408
  Tenner TJ, Hirschmann MM, Withers AC, Hervig RL (2009) Hydrogen partitioning between nominally anhydrous upper mantle minerals and melt between 3 and 5 GPa and applications to hydrous peridotite partial melting. Chem Geol 262:42–56CrossRef
  Tommasi A, Mainprice D, Canova G, Chastel Y (2000) Viscoplastic self-consistent and equilibrium-based modeling of olivine lattice preferred orientations: implications for the upper mantle seismic anisotropy. J Geophys Res 105:7893–7908CrossRef
  Tommasi A, Godard M, Coromina G, Dautria JM, Barsczus H (2004) Seismic anisotropy and compositionally induced velocity anomalies in the lithosphere above mantle plumes: a petrological and microstructural study of mantle xenoliths from French Polynesia. Earth Planet Sci Lett 227:539–556CrossRef
  Tommasi A, Vauchez A, Godard M, Belley F (2006) Deformation and melt transport in a highly depleted peridotite massif from the Canadian Cordillera: implications to seismic anisotropy above subduction zones. Earth Planet Sci Lett 252:245–259CrossRef
  Wang YF (2006) Rheological study of peridotites from Dongqiao area, northern Tibet. Dissertation, China University of Geosciences (Wuhan) (in Chinese)
  Wang XB, Bao PS, Deng WM, Wang FG (1987) Ophiolite in Tibet. Geological Publishing House, Beijing (in Chinese)
  Warren JM, Hauri EH (2014) Pyroxenes as tracers of mantle water variations. J Geophys Res 119:1851–1881. doi:10.​1002/​2013JB010328 CrossRef
  Warren JM, Hirth G (2006) Grain size sensitive deformation mechanisms in naturally deformed peridotites. Earth Planet Sci Lett 248:423–435CrossRef
  Withers AC (2013) On the use of unpolarized infrared spectroscopy for quantitative analysis of absorbing species in birefringent crystals. Am Mineral 98:689–697CrossRef
  Xia B, Xu L, Wei Z, Zhang Y, Wang R, Li J, Wang Y (2008) SHRIMP zircon dating of gabbro from the Donqiao ophiolite in Tibet and its geological implications. Acta Geol Sin 82:528–531 (in Chinese)
  Xia QK, Hao YT, Li P, Deloule E, Coltorti M, Dallai L, Yang X, Feng M (2010) Low water content of the Cenozoic lithospheric mantle beneath the eastern part of the North China Craton. J Geophys Res 115:B07207. doi:10.​1029/​2009JB006694 CrossRef
  Xia QK, Hao YT, Liu SC, Gu XY, Feng M (2013) Water contents of the Cenozoic lithospheric mantle beneath the western part of the North China Craton: peridotite xenolith constraints. Gondwana Res 23:108–118CrossRef
  Yu Y, Xu X, Griffin WL, O’Reilly SY, Xia QK (2011) H2O contents and their modification in the Cenozoic subcontinental lithospheric mantle beneath the Cathaysia block, SE China. Lithos 126:182–197CrossRef
  Zhou MF, Robinson PT (1997) Origin and tectonic setting of podiform chromite deposit. Econ Geol 92:259–262CrossRef
  Zhou MF, Malpas J, Robinson PT, Reynolds P (1997) The dynamothermal aureole of the Dongqiao ophiolite, northern Tibet. Can J Earth Sci 34:59–65CrossRef
  
• 作者单位：Yongfeng Wang (1) (2)
  Huaping Ren (1) (3)
  Zhenmin Jin (1) (2)
  
  1. State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
  2. Global Tectonic Center, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
  3. Geological Exploration Institute of Henan, Zhengzhou, 450000, China
  
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geology
  Mineral Resources
  Mineralogy
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0967

文摘

Mantle peridotites from modern supra-subduction zones (SSZs) are important windows through which we can investigate the geodynamic processes active in the subduction factory, but they are unfortunately rare and hard to access. Most ophiolitic peridotites stem from SSZ settings and are therefore good candidates to explore the water budget and deformation in mantle wedges. We present here an integrated study of the geochemistry, deformation microstructures and water contents of olivine and orthopyroxene from the Dongqiao harzburgites, central Tibet. These peridotites are characterized by an absence of interstitial clinopyroxene, the partial replacement of orthopyroxene by olivine, the highly magnesian olivine and chromium spinel, and remarkable LREE enrichments. These features suggest that the Dongqiao harzburgites are highly depleted and have undergone a high degree (~40 %) of partial melting, followed by infiltration of and interaction with melt while they were part of the mantle wedge. Olivine and orthopyroxene show prominent plastic deformation microstructures and have developed significant crystallographic preferred orientations (CPOs), suggestive of dislocation creep deformation. Fourier transform infrared analyses show that olivine is essentially dry, while orthopyroxene contains an average water content of 70 ± 14 wt ppm. We propose that orthopyroxene largely retains its in-situ water content from the mantle source, while olivine completely loses its water during emplacement. The orthopyroxene water contents fall into the lower end of the range observed in SSZ peridotites. We consider that the high degree of partial melting and the interaction with a water-undersaturated melt contribute to the relatively lower water contents in orthopyroxene from the Dongqiao harzburgites. Based on experimentally determined hydrogen partition coefficients between olivine and orthopyroxene, the water contents of olivine in the mantle source are calculated to be 7–9 wt ppm (or 114–147 ppm H/Si), which is consistent with the observed A-type CPOs in olivine.