www.elsevier.com/locate/tectoTectonophysics 429 (2007) 291–296

Discussion

Reply to the comments of S. Karato on “Petrofabrics and seismicproperties of garnet peridotites from the UHP Sulu terrane (China)”

by Xu et al. [Tectonophysics 421 (2006) 111–127]

Shaocheng Ji a,⁎, Qin Wang b, Zhiqin Xu c

a Département des Génies Civil, Géologique et des Mines, École Polytechnique de Montréal, Montréal, Québec, Canada H3C 3A7b Department of Earth Sciences, Nanjing University, Nanjing 210093, China

c Key Laboratory of Continental Dynamics, Ministry of Land and Resources. Institute of Geology,Chinese Academy of Geological Sciences, Beijing 100037, China

Received 7 September 2006; accepted 13 September 2006Available online 7 November 2006

Abstract

We thank Karato for his interest in our recent paper in Tectonophysics [Xu, Z.Q., Wang, Q., Ji, S.C.. Chen, J., Zeng, L.S., Yang,J.S., Chen, F.Y., Liang, F.H., Wenk, H.R., 2006. Petrofabrics and seismic properties of garnet peridotite from the UHP Sulu terrane(China): Implications for olivine deformation mechanism in a cold and dry subducting continental slab. Tectonophysics 421, 111–127]. However, Karato is incorrect to take water or water-related species (herein referred to generically as ‘water’) as an almostunique cause for any olivine fabric transition in nature no matter what geological conditions are. In this Reply, we will first give asuccinct introduction to the context of the ongoing debate, and then provide some additional arguments in favour of our conclusionthat “the olivine C-type fabric of the Zhimafang garnet-bearing peridotites was formed under the conditions of high pressure, lowtemperature and low water content during the subduction of cold and dry supracrustal rocks of the Yangtze plate”. The map ofolivine slip systems as a function of differential stress and water content, drawn by Karato and coworkers, cannot be reliablyextrapolated to Earth’s interior until relevant scaling laws have been established. The role of high water content on the fabrictransitions is more likely to modify recrystallization kinetics than to switch the dominant slip systems.© 2006 Elsevier B.V. All rights reserved.

Keywords: Olivine; Petrofabrics; Slip systems; Water content; UHP metamorphic rocks; Sulu terrane

1. Context of the ongoing debate

Since Carter and Avé Lallemant (1970) it has beenwell known that [100](010), [100]{0kl} and [001]{100}are dominant slip systems, respectively, at high tem-perature (T) and/or low strain rate (ε)̇, moderate T and/or

⁎ Corresponding author. Tel.: +1 514 340 4711x5134; fax: +1 514 3403970.

E-mail address: sji@polymtl.ca (S. Ji).

0040-1951/$ - see front matter © 2006 Elsevier B.V. All rights reserved.doi:10.1016/j.tecto.2006.09.003

moderate ε,̇ and low T and/or high ε.̇ The informationhas been widely used to establish the relationship be-tween deformation and seismic anisotropy in the uppermantle (e.g., Nicolas and Christensen, 1987; Mainpriceand Silver, 1993; Ji et al., 1994; Saruwatari et al., 2001).Jung and Karato (2001) reported a map of olivine slipsystems as function of differential stress (σ) and watercontent. In this map, [100](010) forming A-type fabric,[001](100) resulting C-type fabric, and [001](010)producing B-type fabric are described as dominant slip

292 S. Ji et al. / Tectonophysics 429 (2007) 291–296

systems at low σ and low water content, moderate σ andhigh water content, and high σ and high water content,respectively. Since then, the presence of high wateractivity (>1000 H/106 Si) has been taken for granted byKarato and coworkers as an almost unique necessarycondition for the development of B-type or C-typefabrics in natural peridotites (e.g., Katayama et al., 2005;Skemer et al., 2006) and in-situ upper mantle (Karato,2002). However, their conclusions are still controversialbecause so far their experimental results have not beenreproducible in other laboratories (e.g., Li et al., 2003a,b;Couvy et al., 2004; Li et al., 2004; Raterron et al., 2004).Yet it is uncertain at all if the slip system map portrayedby Jung and Karato (2001) and Katayama et al. (2004)can be reliably extrapolated to the in-situ upper mantlefor the following reasons: (1) The experiments wereperformed using a Griggs-type solid-medium apparatusand the exact σ and its evolution were unknown for eachrun; only the final stress is estimated from the dislocationdensity of quenched samples. The estimation cannot beprecise because the dislocation density is often hetero-geneous in a sample and even in a grain. Furthermore,the differential stresses applied to the samples areconsiderably higher than the flow stress in the uppermantle. (2) Deformation tests were conducted at muchhigher ε ˙ (typically 10−4 to 10−6 s−1) than those inEarth's interior (10−13 to 10−15 s−1). (3) The experi-mental samples are only a few hundreds of microns thickand olivine grain sizes used are much smaller than thosein the upper mantle. (4) The experimental temperatures(typically 1200–1300 °C) are much higher while theconfining pressures (P<2.2 GPa) are significantly lowerthan those in the subducted continental slab during theultrahigh-pressure (UHP) metamorphism (in the case ofdiscussion). (5) Effects of secondary phases (i.e.,pyroxenes and garnet) are completely ignored becauseonly single crystals or monomineralic aggregates ofolivine were used as starting materials in experimentsand effects of chemical buffering of other componentssuch as orthopyroxene is not taken into account. In ouropinion, their claim that olivine B- or C-type fabrics fromnatural peridotites must be formed in the presence ofhigh water content (>1000 H/106 Si) is nothing morethan speculation.

Meanwhile a group of researchers in Mineral PhysicsInstitute at Stony Brook (USA) and Laboratoire deStructure et Propriétés de l'Etat Solide at Lille (France)havemade a great progress in the understanding of olivinefabric transition. Couvy et al. (2004) performed simpleshear experiments on olivine aggregates at 11 GPa and1400 °C, conditions equivalent to those at depths of330 km. Under these conditions, olivine deforms by

dislocation creep with [001]{hk0} as the dominant slipsystem. They suggested that the dominant slip system inolivine changes with confining pressure but not withwater content. Combining with viscoplastic self-consis-tent modeling of olivine fabrics, Mainprice et al. (2005)used the experimental results to interpret the rapiddecrease of seismic anisotropy in the upper mantlebelow 250 km depth. New experimental data of Dr.Paul Raterron (written personal communication, 2006) bydeforming together dry forsterite single crystals in theorientation allowing either [100] or [001] slip alone along(010) at 2.5 GPa and 7.2 GPa in the 1100–1400 °C range,have clearly shown the transition from [100] slip to [001]slip with increasing pressure in the absence of water. Thetransition of olivine slip systems cannot be due tovariations in water content or differential stresses sincethe experimental conditions were similar at all pressures.Recently theoretical analyses of Durinck et al. (2005)based on first-principle calculations of generalizedstacking faults provided a fundamental explanation forthe pressure sensitivity of slip systems in olivine. Theyconclusively showed that [100](010) plastic shear inducesstrong compressive stresses at the shear plane and resultsin significant hardening with increasing pressure. How-ever, the behaviour of [001](010) glide is the oppositewith much weaker compressive stresses. Based on thecalculations of Peierls stress (Dr. Patrick Cordier, writtenpersonal communication, 2006), they confirmed theresults of Durinck et al. (2005). Both the experimentaland theoretical studies cited above provide importantinsights into pressure-induced fabric transitions. Unfortu-nately, Karato is apparently unaware of these new results.

The fabric transition from a-slip to c-slip has beeninterpreted by Karato and coworkers (e.g., Jung andKarato, 2001; Karato, 2002; Katayama et al., 2004) as aresult of selective-enhanced c-slip relative to a-slip by thepresence of water. Their samples have subjected to a highdegree of recrystallization, no matter a single crystal orpolycrystalline aggregates of olivine used as startingmaterials. What is the role of recrystallization on thedevelopment of olivine B-type and C-type fabrics? In ouropinion, the role of high water content is more likely tomodify recrystallization kinetics (i.e., to enhance grainboundary mobility) than to switch the dominant slipsystems of olivine. It is well known that the physicalprocesses of fabric development by grain boundarymigration (GBM) are different from those by dislocationglide. Previous studies (e.g., Kunze and Avé Lallemant,1981; Karato, 1988) showed that olivine grains with hardorientation (low Schmid factor) dominate the fabric whenGBM recrystallization is significant. Hard grains orientedunfavourably for slip on easy slip system are expected to

Fig. 1. Schematic drawing showing the P–T–t path of the Zhimafangperidotite. The absence of partial melting in the peridotite andsurrounding UHP quartzofeldspathic gneisses, and the preservation ofcoesite indicate consistently a water-poor environment until theserocks were transported into the middle or upper crust.

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accumulate lower dislocation density for a given incre-ment of deformation than soft grains oriented more fa-vourably to undergo dislocation slip (e.g., Karato, 1988).Under the shear stress, grains with lower dislocationdensity will grow at the expense of higher dislocationdensity grains. When [100](010) is the easy slip system,grain boundary migration recrystallization may formeither B-type or C-type fabrics in recrystallized neoblastsbut type-A fabric in porphyroclasts. This may provide analternative interpretation of the fabric transition identifiedfrom the Higashi-Akaishi peridotite body of southwestJapan (Mizukami et al., 2004): A-type fabric for sampleswith coarse granular texture (∼0.6 mm) while B-typefabric for those recrystallized (∼0.1 mm). Our interpreta-tion is consistent with the observations that well-definedsubgrain structure occurs in A-type samples but not inB-type or C-type samples (Jung and Karato, 2001). Inthis sense, the coarse grained olivine (1–20 mm) fromthe Zhimafang garnet peridotites gives the first directevidence for C-type fabric formed by dislocation glide.

In order to form the so-called type-E fabric through(001)[100] slip, Karato and coworkers used an olivinesingle crystal oriented [100] parallel to the applied sheardirection and (001) parallel to the shear plane as thestarting material (Katayama et al., 2004). Clearly theresults are inapplicable to natural peridotites that arepolycrystalline and polymineralic aggregates where eachcrystal has a different orientation. In fact, the develop-ment of the strong fabric (e.g., Fig. 3 of Katayama et al.,2004) in neoblasts recrystallized from such a crystalsheared using (001)[100] system is most likely con-trolled by the initial orientation of the host grain (i.e.,host-control recrystallization) and has nothing to do withthe role of water.

2. Additional evidence for UHP metamorphic rocks

An essential issue in this debate is whether themeasured water contents in olivine provide someconstraints on in-situ water contents during the fabricformation under the UHP metamorphic conditions.Karato asserts that the water has been lost duringtransport to the surface because the solubility of waterincreases with increasing P and/or T, and also thediffusivity of water is high in minerals. However, Karatoseems to take erroneously the solubility, which is themaximum amount of water that can be dissolved inolivine and has been estimated from extrapolation oflaboratory data, as the actual content of water in olivinefrom the Zhimafang peridotites. Xu et al. (2006) clearlyshowed that “the water concentrations in olivine grainsare far below the water solubility in the upper mantle

conditions” and also that “neither a free hydrous fluidexisted during UHP metamorphism nor a significantrelease of dissolved water took place during exhuma-tion”. Karato apparently has limited knowledge of UHPmetamorphic rocks from the Sulu terrane (China) andtheir geological setting. We are pleased to provide someadditional arguments to support the conclusions pre-sented in our original paper (Xu et al., 2006).

Previous petrochemical studies show that the micro-diamond-bearing Zhimafang garnet peridotite body was arelict sliver (970 m long and 170 m wide) of the stronglydepleted mantle (e.g., Yang et al., 1993; Zhang et al., 1994,2000, 2003). The fragment was tectonically inserted intothe subducting continental slabwith extremely low thermalgradient (≤5 °C/km) and subjected toUHPmetamorphismat 221±3 Ma (U–Pb zircon age), 750–950 °C and 6.0–7.5GPa (>180 km depth), and then rapidly exhumed to theEarth's surface (e.g., Zhang et al., 2000; Li et al., 2003a,b;Zhang et al., 2005a,b), as shown in Fig. 1. The peridotiteshave lower CaO, Al2O3, TiO2 and REE contents thanprimitivemantle.MgOdisplays a negative correlationwithTiO2, Na2O, Al2O3 and CaO contents. The petrochemicalcharacteristics indicate that the garnet peridotites have beensubjected to the extraction of∼30 vol.% partial melts (e.g.,Li et al., 2003a,b; Zheng et al., 2005). Because waterstrongly prefers to concentrate in melts during partial

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melting (e.g., Hirth and Kohlstedt, 1996), the refractoryresidue (i.e., Zhimafang garnet peridotites) becameextremely water-poor after such a high degree of partialmelting. Consequently, the water content of the olivineduringUHPmetamorphism [<30wt. ppmH2O in Paterson(1982) calibration] was much lower than the valueestimated from extrapolation of experimental solubility(>360 wt. ppm H2O, Mosenfelder et al., 2006) under thesameTandP conditions. If a mantle rock subjected to 30%partial melting were still water-rich, the “lithosphere–asthenosphere model” of Karato (2002) would be invalideither.

Because olivine was relatively dry (high degree ofundersaturation with water) during the UHP meta-morphism and subsequent HT (nearly isothermal)exhumation, water may be added into olivine whenthe peridotites were transported into the middle or uppercrust where these rocks underwent hydration and ret-rogression at amphibolite and/or greenschist faciesconditions (Fig. 1), as indicated by the presence ofserpentine and other LT hydrous minerals along laterbrittle fractures. The late water gain process is consistentwith the petrological profile of the CCSD-PP1, showingthat serpentinization and chloritization occur mainlyalong the upper and lower boundaries of the Zhimafangperidotite body while fresh peridotites are dominant inits centre part (Liu et al., 2001, Li et al., 2003a,b; Zhanget al., 2005a,b). The measured water contents may notbe exactly reflect in-situ values in olivine during theUHP metamorphism, but certainly yield the upperbound for the water content that olivine might havehad since the peak metamorphism. It is also interestingto note that in order to obtain a larger diffusional lengthfor the peridotite at 800 °C, Karato performed the samecalculation as Xu et al. (2006) but using an erroneousdiffusion coefficient (D) of 10−11 m2/s instead of acorrect value (10−13–10−14 m2/s for iron-bearing oliv-ine, Demouchy and Mackwell, 2003). Even if Karatowere correct to use D=10−11 m2/s, he still would beincorrect because the calculated diffusional lengthshould equal ∼56 m rather than ∼100 m.

The coesite-bearing quartzofeldspathic gneisses sur-rounding the Zhimafang garnet peridotite body wereequally subjected to Triassic subduction-related UHPmetamorphism (e.g., Liu et al., 2001, 2004). Given thatthe crustal materials are more buoyant than the uppermantle, the subducted crust should not be rheologicallyweaker than the upper mantle so that the felsic crust canbe pushed or pulled into the mantle (e.g., Ji and Xia,2002). Only when water is scare or absent, the coldcrustal materials can be as strong as or stronger than themantle rocks. In other words, the residual, severely

dehydrated crustal materials would have been suffi-ciently strong to penetrate into the mantle.

Furthermore, many petrographic and isotropic studieshave consistently shown other strong evidence for a lackof fluid availability during UHP metamorphism andsubsequent HT retrogression of the Dabie–Sulu terrane.The evidence includes: (1) partial preservation of igneousassemblages and textures in UHP metagabbro (e.g.,Wallis et al., 1997; Zhang and Liou, 1997; Chopin, 2003);(2) lack of discernable partial melting in UHP quartzo-feldspathic rocks (Okay, 1993; Liou and Zhang, 1996)and absence of a typical calc-alkaline magmatic arc in theorogen (Fig. 1); (3) preservation of extremely low oxygenisotropic protolith compositions (Zheng et al., 2003 for areview). For instance, in contrast to typical upper mantlewith δ18O values of +2 to +7‰, some eclogites andinterlayered quartzites from the Sulu UHP terrane haveextremely negative δ18O values of −10.4 to −7.3‰ forgarnet, omphacite, phengite, and quartz (Yui et al., 1995).The negative δ18O values were acquired through near-surface meteoric water–rock interactions before thecontinental subduction and UHP metamorphism. Thepreservation of such low oxygen isotropic protolithcompositions suggests that fragments of old and coldcontinental materials were very dry and isolated fromfluid interaction during their descent to mantle depths andlater return to the surface.We refer Karato to the literature.

The extensive preservation of intragranular andintergranular coesite, which is a highly metastable phasein UHP metamorphic rocks exposed to the Earth'ssurface, also provides an important piece of evidencefor the lack of H2O during the UHP metamorphism andsubsequent HTexhumation (Fig. 1) until fracturing at lowtemperature and low pressure (i.e., within the middle orupper crust). Coesite is widespread in not only rheologi-cally strong phases such as garnet, zircon and diamondbut also relatively weak minerals such as dolomite (e.g.,Zhang and Liou, 1996). Experimental studies on thekinetics of coesite–quartz transition in the presence ofsmall amounts of H2O (several hundreds of ppm only)suggest that a residence time less than 1 Ma at 375 °C(Mosenfelder and Bohlen, 1997) or 225 °C (Perrillat et al.,2003) is long enough to transform a coesite grain of100 μm in size completely to quartz. Even if the UHProcks (e.g., the Zhimafang garnet peridotite) were rapidlyexhumed at a consistent rate of 10–15 mm/yr, it wouldtake at least 10–15Ma to reach to the surface from depthsof >150 km. Thus it has been widely accepted that thelack of aqueous fluid inhibits the transformation of coesiteto quartz (Liou and Zhang, 1996; Mosenfelder et al.,2005) as water has significant catalytic effects on trans-formation kinetics (e.g., Rubie, 1990).

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Recent infrared spectra investigations of various UHProcks throughout the world (e.g., Dora–Maria massif ofAlps, Chinese Dabie–Sulu orogenic belt, NorwegianWestern Gneiss Region, South African Roberts Victorkimberlite; Mosenfelder et al., 2005) yield a similarpicture: Coesite included in unfractured host minerals isextremely dry (<100 ppm). Water concentrations in relictcoesite and its immediately surrounding palisade quartzwithin fractured host minerals are also very low(<100 ppm). Around the palisade quartz, however, thepolycrystalline diffuse silica phases are actually chalced-ony containing up to 0.4 wt.% H2O or opal (∼7 wt.%H2O). The above facts indicate that the UHP metamorph-ism and subsequent HT exhumation took place in dryenvironments. The highly hydrated silica phases (i.e.,chalcedony and opal) formed during the development ofbrittle fractures and infiltration of fluid along the cracks atlow temperature (i.e., greenschist- or amphibolite-faciesconditions). The palisade quartz is believed to formduring the early stage of exhumation (i.e., isothermaldecompression, Fig. 1). The large amounts of H2Onecessary to produce chalcedony should take place duringthe last stage of exhumation in the middle or upper crust.

In conclusion, based on the available data, wemaintain that “the olivine C-type fabric of the Zhimafanggarnet-bearing peridotites was formed under the condi-tions of high pressure, low temperature and low watercontent during the subduction of cold and dry supra-crustal rocks of the Yangtze plate”. The map of olivineslip systems as function of differential stress and watercontent, drawn by Jung andKarato (2001) andKatayamaet al. (2004), cannot be reliably extrapolated to Earth'sinterior until relevant scaling laws have been established.We suggested that the role of high water content on thefabric transitions is more likely to modify recrystalliza-tion kinetics than to switch the dominant slip systems.Pressure sensitivity or water content dependence ofolivine slip systems requires more extensive studies andthe rheology and deformationmechanisms of subductingcontinental slabs become an area ripe for further study.

Acknowledgements

We cordially thank Patrick Cordier, David Main-price, and Paul Raterron for helpful discussion.

References

Carter, N.L., Avé Lallemant, H.G., 1970. High temperature flow ofdunite and peridotite. Geol. Soc. Amer. Bull. 81, 2181–2202.

Chopin, C., 2003. Ultrahigh-pressure metamorphism: tracing continentalcrust into the mantle. Earth Planet. Sci. Lett. 212, 1–14.

Couvy, H., Frost, D.J., Heidelbach, F., Nyilas, K., Ungar, T., Mackwell,S., Cordier, P., 2004. Shear deformation experiments of forsterite at11 GPa–1400 °C in the multianvil apparatus. Eur. J. Mineral. 16,877–889.

Demouchy, S., Mackwell, S.J., 2003. Water diffusion in synthetic iron-free forsterite. Phys. Chem. Miner. 30, 486–494.

Durinck, J., Legris, A., Cordier, P., 2005. Pressure sensitivity of olivineslip systems: first-principle calculations of generalized stackingfaults. Phys. Chem. Miner. 32, 646–654.

Hirth, G., Kohlstedt, D., 1996. Water in the oceanic upper mantle:implications for rheology, melt extraction, and the evolution of thelithosphere. Earth Planet. Sci. Lett. 144, 93–108.

Ji, S.C., Xia, B., 2002. Rheology of Polyphase Earth Materials.Polytechnic International Press, Montreal. 260 pp.

Ji, S.C., Zhao, X., Francis, D., 1994. Calibration of shear-wavesplitting in the subcontinental upper mantle beneath activeorogenic belts using ultramafic xenoliths from the CanadianCordillera and Alaska. Tectonophysics 239, 1–27.

Jung, H., Karato, S., 2001. Water-induced fabric transitions in olivine.Science 293, 1460–1463.

Karato, S., 1988. The role of recrystallization in the preferredorientation of olivine. Phys. Earth Planet. Inter. 51, 107–122.

Karato, S., 2002. The Dynamics Structure of the Deep Earth: anInterdisciplinaryApproach. Princeton andOxford, New Jersey, p. 241.

Katayama, I., Jung, H., Karato, S., 2004. New type of olivine fabricfrom deformation experiments at modest water content and lowstress. Geology 32, 1045–1048.

Katayama, I., Karato, S., Brandon, M., 2005. Evidence of high watercontent in the deep upper mantle inferred from deformationmicrostructures. Geology 33, 613–616.

Kunze, F.R., Avé Lallemant, H.G., 1981. Non-coaxial experimentaldeformation of olivine. Tectonophysics 74, T1–T13.

Li, L., Raterron, P., Weidner, D., Chen, J.H., 2003a. Olivine flowmechanisms at 8 GPa. Phys. Earth Planet. Inter. 138, 113–129.

Li, T.F., Yang, J.S., Zhang, R.Y., 2003b. Peridotite from the pre-pilothole (PP1) of Chinese continental scientific drilling project and itsbearing on depleted and metasomatic upper mantle. Acta Geol.Sin. 77, 492–509.

Li, L., Weidner, D., Raterron, P., Chen, J.H., Vaughan, M., 2004. Stressmeasurements of deforming olivine at high pressure. Phys. EarthPlanet. Inter. 143, 357–367.

Liu, F.L., Xu, Z.Q., Katayama, I., Yang, J.S., Maruyama, S., Liou, J.G.,2001.Mineral inclusions in zircons of para- and orthogneiss from pre-pilot drillhole CCSD-PP1, Chinese Continental Scientific Drillingproject. Lithos 59, 199–215.

Liu, F.L., Xu, Z.Q., Liou, Z.G., Song, B., 2004. SHRIMP U–Pb agesof ultrahigh-pressure and retrograde metamorphism of gneisses,south-western Sulu terrane, eastern China. J. Metamorph. Geol. 22,315–326.

Liou, J.G., Zhang, R.Y., 1996. Occurrence of intragranular coesite inultrahigh-P rocks from the Sulu region, eastern China: implica-tions for lack of fluid during exhumation. Am. Mineral. 81,1217–1221.

Mainprice, D., Silver, P., 1993. Interpretation of SKS-waves usingsamples from the sub-continental lithosphere. Phys. Earth Planet.Inter. 78, 257–280.

Mainprice, D., Tommasi, A., Couvy, H., Cordier, P., Frost, D.J., 2005.Pressure sensitivity of olivine slip systems and seismic anisotropyof Earth's upper mantle. Nature 433, 731–733.

Mizukami, T., Wallis, S.R., Yamamoto, J., 2004. Natural examples ofolivine lattice preferred orientation patterns with a flow-normal a-axis maximum. Nature 427, 432–436.

296 S. Ji et al. / Tectonophysics 429 (2007) 291–296

Mosenfelder, J.L., Bohlen, S.R., 1997. Kinetics of the coesite to quartztransformation. Earth Planet. Sci. Lett. 153, 133–147.

Mosenfelder, J.L., Schertl, H.P., Smyth, J.R., Liou, J.G., 2005. Factorsin the preservation of coesite: the importance of fluid infiltration.Am. Mineral. 90, 779–789.

Mosenfelder, J.L., Deligne, N.I., Asimow, P.D., Rossman, G.R., 2006.Hydrogen incorporation in olivine from 2–12 GPa. Am. Mineral.91, 285–294.

Nicolas, A., Christensen, N.I., 1987. Formation of anisotropy in uppermantle peridotites— a review. In: Fuchs, K., Froideoaux, C. (Eds.),Composition, Structure and Dynamics of the Lithosphere–Astheno-sphere System. Trans. ed.Washington, D.C.: AGU 16, pp. 407–433.

Okay, A.I., 1993. Petrology of a diamond and coesite-bearingmetamorphic terrain: Dabie Shan, China. Eur. J. Mineral. 5,659–675.

Paterson, M.S., 1982. The determination of hydroxyl by infraredabsorption in quartz silicate glasses and similar materials. Bull.Miner. 105, 20–29.

Perrillat, J.P., Daniel, I., Lardeaux, J.M., Cardon, H., 2003. Kinetics ofthe coesite–quartz transition: application to the exhumation ofultrahigh-pressure rocks. J. Petrol. 44, 773–788.

Raterron, P., Wu, Y., Weidner, D.J., Chen, J., 2004. Low-temperatureolivine rheology at high pressure. Phys. Earth Planet. Inter. 145,149–159.

Rubie, D.C., 1990. Role of kinetics in the formation and preservationof eclogite. In: Carswell, D.A. (Ed.), Eclogite Facies Rocks.Chapman and Hall, New York, pp. 111–140.

Saruwatari, K., Ji, S.C., Long, C.X., Salisbury, M., 2001. Seismicanisotropies of mantle xenoliths and constraints on the upper mantlestructures beneath the southern Canadian Cordillera. Tectonophysics339, 399–422.

Skemer, P., Katayama, I., Karato, S.I., 2006. Deformation fabrics ofthe Cima di Gagnone peridotite massif, Central Alps, Switzerland:evidence of deformation at low temperatures in the presence ofwater. Contrib. Mineral. Petrol. 152, 42–51.

Wallis, S.R., Ishiwatari, A., Hirajima, T., Ye, K., Guo, J., Nakamura, D.,Kato, T., Zhai,M., Enami,M., Cong, B., Banno, S., 1997. Occurrenceand field relationship of ultrahigh-pressure metagranitoid and coesiteeclogite in the Sulu terrane, eastern China. J. Geol. Soc. (Lond.) 154,45–54.

Xu, Z.Q., Wang, Q., Ji, S.C., Chen, J., Zeng, L.S., Yang, J.S., Chen, F.Y.,Liang, F.H., Wenk, H.R., 2006. Petrofabrics and seismic properties

of garnet peridotite from the UHP Sulu terrane (China): implicationsfor olivine deformation mechanism in a cold and dry subductingcontinental slab. Tectonophysics 421, 111–127.

Yang, J.J., Godard, G., Kienast, J.R., Lu, Y., Sun, J., 1993. Ultrahigh-pressure (60 kbars) magnesite-bearing garnet peridotites fromnortheastern Jiangsu, China. J. Geol. 101, 541–554.

Yui, T.F., Rumble, D., Lo, C.H., 1995. Unusually low δ18O ultrahigh-pressure metamorphic rocks from the Sulu terrain, eastern China.Geochim. Cosmochim. Acta 59, 2859–2864.

Zhang, R.Y., Liou, J.G., 1996. Coesite inclusions in dolomite fromeclogite in the southern Dabie Mountains, China: the significanceof carbonate minerals in UHPM rocks. Am. Mineral. 81,181–186.

Zhang, R.Y., Liou, 1997. Partial transformation of gabbro to coesite-bearing eclogite from Yangkou, the Sulu terrane, eastern China.J. Metamorph. Geol. 15, 183–202.

Zhang, R.Y., Liou, J.G., Cong, B.L., 1994. Petrogenesis of garnet-bearing ultramafic rocks and associated eclogites in the Su-Luultrahigh-P metamorphic terrane, eastern China. J. Metamorph.Geol. 12, 169–186.

Zhang, R.Y., Liou, J.G., Yang, J.S., Yui, T.F., 2000. Petrochemicalconstraints for dual origin of garnet peridotites from the Dabie–Sulu UHP terrane, eastern-central China. J. Metamorph. Geol. 18,149–166.

Zhang, R.Y., Liou, J.G., Yang, J.S., Ye, K., 2003. Ultrahigh-pressuremetamorphism in the forbidden zone: the Xugou garnet period-itite, Sulu terrane, eastern China. J. Metamorph. Geol. 21,539–550.

Zhang, R.Y., Yang, J.S., Wooden, J.L., Liou, J.G., Li, T.F., 2005a.U–Pb SHRIMP geochronology of zircon in garnet peridotite fromthe Sulu UHP terrane, China. Earth Planet. Sci. Lett. 237, 729–743.

Zhang, Z.M., Zhang, J.F., You, Z.D., Shen, K., 2005b. Ultrahigh-pressure metamorphic P–T–t path of the Sulu orogenic belt,eastern central China. Acta Petrol. Sin. 21, 257–270.

Zheng, Y.F., Fu, B., Gong, B., Li, L., 2003. Stable isotope geochemistryof ultrahigh pressure metamorphic rocks from the Dabie–Suluorogen in China: implications for geodynamics and fluid regime.Earth-Sci. Rev. 62, 105–161.

Zheng, J.P., Zhang, R.Y., Griffin, W.L., Liou, J.G., O'Reilly, S.Y.,2005. Heterogeneous and metasomatized mantle recorded by traceelements in minerals of the Donghai garnet peridotites, Sulu UHPterrane, China. Chem. Geol. 221, 243–259.