Yong-Fei ZHENG a,*
a CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
* corresponding author's email: yfzheng@ustc.edu.cn
Full Text (7.5 Mb PDF)←
Abstract
Ultrahigh-pressure (UHP) terranes as well as UHP metamorphic minerals and rocks represent a special natural laboratory to investigate the geodynamics and fluid regime during subduction and exhumation of continental crust. Studies of UHP rocks have represented a new frontier in the earth sciences during the past two decades, significantly advancing our understanding of geological processes in continental subduction zones. This is particularly so from intensive studies of geochemical records in deeply subducted continental crustal rocks from the Dabie-Sulu orogenic belt in China. Such studies have addressed the following issues: the time and duration of UHP metamorphism, the origin and activity of metamorphic fluid during continental collision, and element mobility in continental subduction zones. This extends metamorphic chemical geodynamics of subduction zones from the oceanic crust to the continental crust, enabling important contributions to development of the plate tectonic theory.
Keywords: Continental subduction, UHP metamorphism, plate tectonics, metamorphic geochemistry, chemical geodynamics
1. Introduction
The study of ultrahigh-pressure (UHP) metamorphism and continental deep-subduction was initiated by findings of coesite (Chopin, 1984; Smith, 1984) and diamond (Sobolev and Shatsky, 1990; Xu et al., 1992) in metamorphic rocks of supracrustal origin. These findings have provided compelling evidence that segments of the continental crust were subducted to mantle depths in excess of 100 km and returned to the surface during continental collision orogeny. This challenges the precept in the plate tectonics theory that the continental crust cannot be subducted to mantle depths because of its lower density than the oceanic crust. Thus far, 22 coesite- and diamond-bearing UHP terranes have been recognized in the world; most of them are of Phanerozoic ages (Chopin, 2003; Liou and Ernst, 2008). These UHP terranes lie within major continental collision belts and extend for several hundred km or more; most are in Eurasia (e.g., Alps, Norway, Erzgebirge, Kokchetav, Tianshan, Himalaya, Dabie-Sulu), with rare examples in Africa, South, Central and North America and Antarctica. These deep processes would not only result in phase changes and mineralogical reactions within UHP slabs, but also bring about crust-mantle interactions in continental subduction zones.
A group of Chinese earth scientists were involved in the study of UHP terranes as soon as coesite (Okay et al., 1989, Wang et al., 1989) and diamond (Xu et al., 1992) were identified in eclogites from the Dabie orogen, east-central China. Besides Dabie, five additional coesite- and diamond-bearing UHP terranes have been discovered in China, including Sulu (Enami and Zang, 1990), North Qaidam (Yang et al., 2001), Altun Tagh (Liu et al., 2002), Western Tianshan (Zhang et al., 2002), and North Qinling (Yang et al., 2003). Some special textures of mineral exsolution were also discovered in UHP metamorphic rocks (Ye et al., 2000; Song et al., 2005; Liu et al., 2007a, b), suggesting a possible origin of these rocks from depths in excess of 200 to 300 km. These six UHP terranes occur from east to west along the central orogenic belt of China, forming in the Early Paleozoic and Early Mesozoic, respectively. All UHP rocks consist mainly of felsic and intermediate gneissic rocks with minor eclogites and garnet peridotites. Nevertheless, the mafic-ultramafic rocks appear to have originated from different tectonic settings and were subjected to coeval UHP metamorphism, deformation, and retrogression with their enclosing granitic gneisses and supracrustal rocks. Since UHP eclogites and garnet peridotites more easily preserve petrological and geochemical relics of the UHP stages, they have been studied more intensively to constrain the major processes attending continental subduction, collision and subsequent exhumation. This is particularly so for these rock types in the Dabie and Sulu terranes (e.g., Wang et al., 1995; Cong, 1996; Li et al., 1999; Jahn et al., 2003; Zheng et al., 2003a, 2009a; Xu et al., 2006; Zhang et al., 2009a).
The study of UHP metamorphism and continental deep-subduction has greatly promoted the development of solid earth sciences in China. As illustrated by Fig. 1, there are 26 papers in principal affiliation with Chinese institutions that are among the most cited 100 papers for this increasingly recognized topic. While in the past Chinese scientists failed to make their own contributions to the establishment of the plate tectonics theory, at present they highly contribute to its development with respect to continental dynamics. This paper mainly focuses on the progress in metamorphic chemical geodynamics based on studies of UHP rocks from the Dabie-Sulu orogenic belt since no equivalent studies of deeply subducted continental crustal rocks are available from the other UHP terranes in the world.
2. Timing of UHP metamorphism
Determining the age of UHP metamorphism holds the key to unraveling the geodynamics of continental subduction and exhumation. This is particularly so for UHP eclogites in the Dabie-Sulu orogenic belt that resulted from subduction of the South China Block beneath the North China Block. This belt contains one of the largest (>30,000 km2) and best-exposed two UHP metamorphic terranes (Carswell and Compagnoni, 2003). There are three very important geochemical anomalies in the Dabie-Sulu UHP rocks: excess argon in phengite (Li et al., 1994), a negative oxygen isotope anomaly (Yui et al., 1995; Zheng et al., 1996), and a positive Nd isotope anomaly (Jahn et al., 1996). These provide us an excellent opportunity to study the physico-chemical changes that occurred during subduction and exhumation of the continental crust.
Geochronology of UHP metamorphic event is a key to understanding subduction and exhumation of the continental crust. Because eclogite has mineral paragenesis of garnet + omphacite + phengite ± rutile, mineral Sm-Nd isochrons have been successfully used to date eclogitization. By means of this classic method, Li et al. (1993) first determined that the Dabie-Sulu UHP metamorphism occurred in the Triassic. Later TIMS and SIMS zircon U-Pb dating gave Early Paleozoic and Neoproterozoic ages for some eclogites in this region, casting doubt on reliability of the Triassic age for UHP metamorphism. Finally, it has been realized that the optical purity of eclogitic minerals is critical to success the Sm-Nd isochron dating (Li et al., 2000). Furthermore, inspection of mineral O isotope equilibrium in the isochron minerals provides a test to the validity of mineral Sm-Nd isochrons in UHP eclogites and gneisses (Zheng et al., 2002, 2003b; Xie et al., 2004). Consequently, the Triassic eclogite-facies UHP metamorphic event is verified by SHRIMP U-Pb dating of metamorphically grown zircons in combination with identification of either mineral inclusions (Liu and Xu, 2004; Liu et al., 2004a, b) or REE distribution patterns (Li et al., 2005), or both (Liu et al., 2006a, 2006b, 2008).
While the Dabie-Sulu UHP metamorphic event is resolved as having occurred in the Triassic, there are two contrasting views on its exact age. Hacker et al. (1998, 2000) suggested an age of ~245 Ma based on zircon U-Pb dates, whereas Li et al. (2000) preferred an age of 226±2 Ma based on mineral Sm-Nd isochrons. This controversy has more recently been resolved by SHRIMP U-Pb dating of coesite-bearing domains of metamorphic zircon (Wan et al., 2005; Liu et al., 2006a, 2008), bracketing the UHP metamorphic event between 241±2 Ma and 226±2 Ma (Fig. 2a). In doing so, the identification of mineral inclusions in metamorphically grown zircon has played an important role in distinguishing the peak UHP phase from HP eclogite- and amphibolite-facies metamorphic events.
3. Duration of the UHP metamorphism
Highly negative δ18O values are a very remarkable feature observed in UHP metamorphic rocks from the Dabie-Sulu orogenic belt (Fig. 3). They occur not only in rock-forming minerals of UHP eclogite, granitic gneiss and quartz schist (Rumble and Yui, 1998; Zheng et al., 1998, 1999; Fu et al., 1999; Tang et al., 2008a), but also in granitic minerals such as garnet (Zheng et al., 2007a) and zircon (Tang et al., 2008b). The negative oxygen isotope anomalies represent four global extremes, including the most negative δ18O values for (1) metamorphic minerals (Rumble et al., 2003; Zheng et al., 2003a), (2) intrusive minerals (Zheng et al., 2007a), (3) zircon of magmatic origin (Zheng et al., 2004; Valley et al., 2005; Tang et al., 2008b), and (4) zircon of metamorphic origin (Zheng et al., 2004). These low δ18O values have been interpreted to record the meteoric isotope signature of the cold paleoclimate that predates the snowball Earth event in the middle Neoproterozoic (Zheng et al., 2007a).
Preservation of the extreme 18O depletion in the Dabie-Sulu UHP rocks provides a key example of chemical competition between thermodynamics and kinetics during UHP metamorphism at mantle depths. While the thermodynamics always tends to decline the δ18O difference between the supracrustal protolith and the mantle in order to drive them toward O isotope homogenization, the kinetics requires enough time for the homogenization to be completed at given P-T conditions (depending on the amount of fluid passing through the UHP rocks and driving fluid-mineral O exchange). The competition between the two physico-chemical parameters determines the final status of the δ18O values recorded in the UHP mineral assemblages. Accordingly, Zheng et al. (1998) estimated a timescale of 10 to 20 Myr for the UHP metamorphism at mantle depths (Fig. 4) based on the preservation of negative O isotope anomaly in the UHP minerals and the kinetics of mineral O transport by diffusion and dissolution-recrystallization under UHP conditions. This estimate is quantitatively confirmed by SHRIMP U-Pb dating on different types of metamorphic zircon (Fig. 2), which indicates that entire UHP metamorphic event in the coesite stability field lasted 15±2 Myr (Hacker et al., 2006; Liu et al., 2006b; Wu et al., 2006). Thus, both subduction and exhumation processes of the continental crust take place at faster rates than those of the oceanic crust, with short residence time of supracrustal rocks at mantle depths. These processes were imaged as if frying an icecream by boiling oil without melting (Zheng et al., 2003a). This interpretation also removes the doubt that the occurrence of negative δ18O UHP rocks could indicate their formation by dynamic collision of two continental blocks at lower crustal levels without one of them being deeply subducted to mantle depths.
4. Fluid regime in continental subduction zones
Numerous studies have revealed the widespread existence of diverse water species in minerals at UHP conditions (Zheng, 2009b), including structural hydroxyl and molecular water (occurring as aqueous inclusions of different size) in the minerals usually considered stoichiometrically anhydrous (namely the nominally anhydrous minerals). The presence of molecular water in metamorphic minerals was detected by the micro-FTIR and TEM techniques (Su et al., 2002; Wu et al., 2004; Meng et al., 2009). Total water and molecule water were quantified by total and stepwise extraction analyses, respectively, using the TC/EA-MS online technique (Chen et al., 2007a; Gong et al., 2007a). Further distinction in the fluid origin between the structural hydroxyl and molecular water can be made by the hydrogen isotope analysis, because the molecular water is depleted in deuterium relative to the structural hydroxyl at thermodynamic equilibrium (Chen et al., 2007a; Gong et al., 2007b). Thus, the UHP minerals would act as water sinks (with the maximum water solubility at the peak UHP conditions) during the subduction on one hand, and as water sources during exhumation on the other hand (Zheng, 2009b). Occurrence of coesite pseudomorph as inclusion in allanite from allanite-quartz veins within UHP eclogite indicates fluid flow in the UHP regime (Zhang et al., 2008).
Many studies have been devoted to petrology, stable isotopes, fluid inclusions and mineral water contents in the Dabie-Sulu UHP metamorphic rocks. The results indicate that the scale of fluid flow is very small during the UHP metamorphism of continental crustal rocks (Zheng et al., 1999; Rumble et al., 2000; Fu et al., 2001). Inspection of the relationship between the distance, petrography and δ18O values of adjacent samples from the main hole of Chinese Continental Scientific Drilling (CCSD) reveals O isotope heterogeneities between the different and same lithologies on scales of 20 to 50 cm (Chen et al., 2007b), corresponding to the maximum scales of fluid mobility during the continental collision. However, the fluid activity became significantly large during the initial exhumation because waters derived from the decomposition of hydrous UHP minerals and the exsolution of structural hydroxyl and molecular water in nominally anhydrous UHP minerals can be accumulated to form the retrograde fluid (Chen et al., 2007a; Sheng et al., 2007; Zheng, 2009b). This is indicated by negative correlations between water concentration and hydrogen isotope composition of omphacite and garnet from UHP eclogites (Fig. 5). The decreasing water contents of omphacite and garnet with increasing δD values are caused by a solubility decrease of the D-depleted molecular water in the two UHP minerals with decreasing pressure.
It has been well established that subduction of the altered basaltic oceanic crust and overlying sediments is characterized by significant release of aqueous fluid from metamorphosing slabs (Peacock, 1990; Jarrard, 2003; Bebout, 2007). However, this appears not to be the case for the deep subduction of continental crust. In particular, the exhumation of deeply subducted continental crust is characterized by profound flux of aqueous fluid out from UHP metamorphic minerals due to the decomposition of hydrous minerals and the exsolution of structural hydroxyl and molecular water from nominally anhydrous minerals (Zheng, 2009b). This recognition provides a resolution to the controversy on the origin of retrograde fluid in subduction zones. The traditional viewpoint holds that fluids enhancing retrograde alteration of HP and UHP metamorphic rocks originate from external infiltration at shallow depths (e.g., Yardley et al., 2000; Guiraud et al., 2001; Proyer, 2003). In contrast, retrograde fluids is suggested to derive from the decomposition of hydrous minerals and the exsolution of structural-bound hydroxyl within UHP minerals during decompression exhumation (e.g., Vallis and Scambelluri, 1996; Zheng et al., 1999; Li et al., 2004). A study of fluid inclusions in rutile from UHP eclogites gave a narrow range of homogenization temperatures but a wide range of salinities for aqueous inclusions that were trapped during the exhumation (Ni et al., 2008). This suggests mixing of two fluids, with the high salinity one from the decomposition of hydrous minerals but low salinity one from the exsolution of structural hydroxyl and molecular water.
5. Element mobility in deeply subducted continental crustal rocks
By comparing the composition of HP metamorphic rocks to their protoliths, a number of studies indicate considerable removal of LILE and/or LREE from metabasites during subduction of the oceanic crust to eclogite-facies conditions (e.g., Becker et al., 2000; Scambelluri et al., 2001; John et al., 2004). On the other hand, mafic rocks do not lose significant amounts of trace elements during HP metamorphism up to eclogite-facies (e.g., Chalot-Prat et al., 2003; Spandler et al., 2004; Volkova et al., 2004). This implies the decoupling between dehydration and trace element loss during prograde HP metamorphism. Therefore, it has been intriguing how elements are liberated from subducting crusts. This principally concerns the degree and mechanism of element transport with respect to open or closed systems during prograde HP-UHP metamorphism in oceanic subduction zones. It is possible that the subducting slab does not release abundant fluid until a major dehydration reaction like antigorite breakdown (Ulmer and Trommsdorff, 1995; Schmidt and Poli, 1998; Scambelluri and Philippot, 2001), and thus rocks behave as relatively closed systems up to HP-UHP conditions (Spandler et al., 2004). After that, the fluid moves and enhances element mobility and melting or supercritical fluid production in other rock reservoirs like mafic or pelitic rocks. Because the high solubility of trace elements occurs in hydrous melts and supercritical fluids (Kessel et al., 2005; Hermann et al., 2006), their formation or not during subduction-zone metamorphism may play a critical role in dictating the coupling or decoupling of dehydration and trace element loss (Zhao et al., 2007; Xia et al., 2008).
SHRIMP U-Pb dating on different types of zircons from UHP metamorphic rocks indicates that zircon growth is dictated by episodic activity of metamorphic fluid during subduction and exhumation of the continental crust (Li et al., 2004; Wu et al., 2006; Zhao et al., 2006; Zheng et al., 2007b), suggesting Zr and Si mobility at mantle depths in subduction zones. Furthermore, omphacite, garnet, paragonite, kyanite, rutile and zircon is present in UHP kyanite-quartz vein within eclogite (Li et al., 2004; Zheng et al., 2007b; Wu et al., 2009), indicating relative enrichment of Na, Si, Al, HFSE and HREE in metamorphic fluid. The high solubilities of Al, HFSE and HREE are required to precipitate sufficient amounts of garnet, kyanite, rutile and zircon from the fluid as a response to changes in temperature, pressure or chemical potential. It can only be achieved by a substantial extent of Al-Si complexing with relative enrichment of HFSE and HREE in the supercritical aqueous fluid (Wu et al., 2009; Zheng, 2009b).
Zheng et al. (2005) made a combined in-situ study of U-Pb and Lu-Hf isotopes in zircon from UHP eclogite and granitic gneiss, leading to the first finding of decreased 176Lu/177Hf ratios but increased 176Hf/177Hf isotope ratios for metamorphic growth (Fig. 6). This finding has been confirmed by later studies (Wu et al., 2006; Liu et al., 2008), suggesting chemical exchange between zircon-grown medium and HREE-rich garnet. With the advance of combined LA-MC-ICPMS and LA-ICPMS techniques, simultaneous in-situ analyses of trace elements, U-Th-Pb and Lu-Hf isotopes can be made in the same volume of a single zircon (Yuan et al., 2008; Xie et al., 2008). This provides insights into metamorphic zirconology with implications for fluid action on the recrystallization and growth of zircon during subduction-zone metamorphism. As a consequence, metamorphic recrystallization is subdivided into three mechanisms of solid-state transformation, replacement alteration and dissolution reprecipitation, and the metamorphic growth into new precipitation from aqueous fluid or hydrous melt (Xia et al., 2009, 2010; Chen et al., 2010).
From geochemical analyses of mid-T/UHP eclogite and granitic gneiss from core samples of the CCSD main hole, Zhao et al. (2007) found large variations in the abundance of elements like SiO2, LREE and LILE at the contact between eclogite and granitic gneiss, indicating their mobility between different slice components. On the other hand, Tang et al. (2007) observed high LILE mobility but REE and HFSE immobility within UHP eclogites in which trace element distribution equilibrium is approached between garnet and clinopyroxene. It is known that the supercritical fluid attending the UHP conditions mainly comprises SiO2 + Al2O3 + CaO +MgO +FeO +Na2O + H2O, and is enriched in LREE, HFSE, P, V, Sr, Ba and Pb (Zhang et al., 2008). From a comprehensive study of metamorphic zirconology, Xia et al. (2010) suggested that a supercritical fluid transported LREE, HREE, Th, U and HFSE in accessory minerals to recrystallized zircons during subduction-zone metamorphism.
Variable extents of fluid/melt metasomatism are evident at contacts between contrasting lithological units (e.g., Malaspina et al., 2006a, b; Zhao et al., 2007). This is particularly so for some UHP peridotites, in which melt-peridotite reactions at UHP conditions represent an analogue to crust-mantle interaction in continental subduction zones. However, there is no documentation that these orogenic peridotites belong to the mantle wedge above the subducted continental slab. In other words, it is only assumed to be the mantle wedge without any demonstration of its origin (e.g., Zheng et al., 2008; Zhang et al., 2009b). Available Re-Os isotope data argue against the assumption of mantle wedge for the peridotites (Yuan et al., 2007; Zheng et al., 2009b). In this regard, the observed metasomatism in the UHP peridotites has nothing to do with not only the crust-mantle interaction but also fluid mobility and output from the continental slab.
6. Concluding remarks
The plate tectonics theory, which has influenced nearly all branches of the earth sciences, has its roots in the great upsurge of research on the oceanic crust and its deep subduction. By introducing the basic idea that the oceanic crust is recycled from the Earth's surface into the mantle, Armstrong (1968) first recognized the very important implications of geochemical recycling for crust and mantle evolution. Chemical geodynamics, firstly proposed by Allegre (1982) and further propogated by Zindler and Hart (1986), is primarily a field focusing on mantle geochemistry. Now it has been developed as an integrated study of the chemical structure and tectonic evolution of geospheres, extending from geochemical recycling in oceanic subduction zones to HP and UHP metamorphic reworking in both oceanic and continental subduction zones (Bebout, 2007; Zheng et al., 2009a). This enables to trace the possible contribution of deeply subducted continental crust to mantle geochemical heterogeneity.
Through independent and cooperative research efforts, Chinese geochemists have contributed to elucidate of many important problems by seeking answers to questions such as: (1) which geochemical processes occur during subduction and exhumation of the continental crust? (2) how can geochemical records be used to distinguish in-situ from exotic UHP rocks with respect to the enclosing country rocks? (3) what kind of crust-mantle interaction takes place when continental slices are subducted to mantle depths? (4) how does the dehydration of UHP metamorphic minerals during exhumation provide internally-derived fluid for metamorphic veining and amphibolite-facies retrogression? (5) how does the dehydration melting of UHP metamorphic rocks during exhumation produce varying degrees of migmatization and even K-rich magmatism? (6) which mechanism and rate of ascent prevent UHP mineral assemblages from being completely obliterated by metamorphic overprinting and partial melting during exhumation? (7) how can we recognize and distinguish post-collisional melting products with contrasting sources between the subducted and obducted continental lithospheres? (8) how can we quantify element mobility via aqueous fluid, hydrous melt and supercritical fluid during the continental subduction-zone metamorphism? As a consequence, contributions from the Chinese geochemical community have greatly facilitated the understanding of geodynamic processes attending the overall evolution of convergent plate margins: from oceanic crust subduction to continental collision (Zheng et al., 2009c).
Acknowledgments
This study was supported by funds from the Chinese Ministry of Science and Technology (2009CB825004) and the Natural Science Foundation of China (40921002). Thanks are due to Gray E. Bebout and Marco Scambelluri for their comments that helped improvement of the presentation.
References
Allegre C.J. (1982) Chemical geodynamics. Tectonophysics 81, 109-132.
Amstrong R.L. (1968) A model for Sr and Pb isotope evolution in a dynamic Earth. Rev. Geophys. 6, 175-199.
Bebout G.E. (2007) Metamorphic chemical geodynamics of subduction zones. Earth Planet. Sci. Lett. 260, 373-393.
Becker H., Jochum K.P. and Carlson R.W. (2000) Trace element fractionation during dehydration of eclogites from high-pressure terranes and the implications for element fluxes in subduction zones. Chem. Geol. 163, 65-99.
Chalot-Prat F., Ganne J. and Lombard A. (2003) No significant element transfer from the oceanic plate to the mantle wedge during subduction and exhumation of the Tethys lithosphere (Western Alps). Lithos 69, 69-103.
Carswell D.A. and Compagnoni R. (2003) Ultrahigh Pressure Metamorphism. European Mineralogical Union Notes in Mineralogy, vol. 5, 508 pp.
Chen R.-X., Zheng Y.-F., Gong B., Zhao Z.-F., Gao T.-S., Chen B. and Wu Y.-B. (2007a) Origin of retrograde fluid in ultrahigh-pressure metamorphic rocks: constraints from mineral hydrogen isotope and water content changes in eclogite-gneiss transitions in the Sulu orogen. Geochim. Cosmochim. Acta 71, 2299-2325
Chen R.-X., Zheng Y.-F., Gong B., Zhao Z.-F., Gao T.-S., Chen B. and Wu Y.-B. (2007b) Oxygen isotope geochemistry of ultrahigh-pressure metamorphic rocks from 200-4000 m core samples of the Chinese Continental Scientific Drilling. Chem. Geol. 242, 51-75.
Chen R.-X., Zheng Y.-F. and Xie L.W. (2010) Metamorphic growth and recrystallization of zircon: distinction by simultaneous in-situ analyses of trace elements, U-Th-Pb and Lu-Hf isotopes in zircons from eclogite-facies rocks in the Sulu orogen. Lithos 114, 132-154.
Chopin C. (1984) Coesite and pure pyrope in high-grade blueschists of the western Alps: a first record and some consequence. Contrib. Mineral. Petrol. 86, 107-118.
Chopin C. (2003) Ultrahigh-pressure metamorphism; tracing continental crust into the mantle. Earth Planet. Sci. Lett. 212, 1-14.
Cong B.L. (1996) Ultrahigh-Pressure Metamorphic Rocks in the Dabieshan-Sulu Region of China. Science Press, Beijing, 224 pp.
Enami M. and Zang Q. (1990) Quartz pseudomorph after coesite in eclogites from Shandong Province, east China. Am. Mineral. 75, 381-386.
Ernst W.G. and Liou J.G. (2008) High- and ultrahigh-pressure metamorphism: Past results and future prospects. Am. Mineral. 93, 1771-1786.
Fu B., Zheng Y.-F., Wang Z.-R., Xiao Y.-L., Gong B. and Li S.G. (1999) Oxygen and hydrogen isotope geochemistry of gneisses associated with ultrahigh pressure eclogites at Shuanghe in the Dabie Mountains. Contrib. Mineral. Petrol. 134, 52-66.
Fu B., Touret J.L.R. and Zheng Y.-F. (2001) Fluid inclusions in coesite-bearing eclogites and jadeite quartzites at Shuanghe, Dabie Shan, China. J. Metamorph. Geol. 19, 529-545.
Gong B., Zheng Y.-F. and Chen R.-X. (2007a) A TCEA-MS online method for determination of hydrogen isotope composition and water concentration in geological samples. Rapid Commun. Mass Spectrom. 21, 1386-1392.
Gong B., Zheng Y.-F. and Chen R.-X. (2007b) TC/EA-MS online determination of hydrogen isotope composition and water concentration in eclogitic garnet. Phys. Chem. Minerals 34, 687-698.
Guiraud M., Powell R. and Rebay G. (2001) H2O in metamorphism and unexpected behaviour in the preservation of metamorphic mineral assemblages. J. Metamorph. Geol. 19, 445-454.
Hacker B.R., Ratschbacher L., Webb L., Ireland T., Walker D. and Dong S. (1998) U/Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie orogen, China. Earth Planet. Sci. Lett. 161, 215-230.
Hacker B.R., Ratschbacher L., Webb L., McWilliams M.O., Ireland T., Calvert A., Dong S., Wenk H.-R. and Chateigner D. (2000) Exhumation of ultrahigh-pressure continental crust in east central China: Late Triassic-Early Jurassic tectonic unroofing. J. Geophys. Res. B105, 13339-13364.
Hacker B.R., Wallis S.R., Ratschbacher L., Grove M. and Gehrels G. (2006) High-temperature geochronology constraints on the tectonic history and architecture of the ultrahigh-pressure Dabie-Sulu orogen. Tectonics 25, TC5006, doi: 10.1029/ 2005TC001937.
Hermann J., Spandler C., Hack A. and Korsakov A.V. (2006) Aqueous fluids and hydrous melts in high-pressure and ultra-high pressure rocks: Implications for element transfer in subduction zones. Lithos 92, 399-417.
Jahn B.-m., Cornichet J., Cong B.L. and Yui T.-F. (1996) Ultrahigh-εNd eclogites from an ultrahigh-pressure metamorphic terrane of China. Chem. Geol. 127, 61-79.
Jahn B.-m., Rumble D. and Liou J.G. (2003) Geochemistry and isotope tracer study of UHP metamorphic rocks. European Mineralogical Union Notes in Mineralogy 5, 365-414.
Jarrard R.D. (2003) Subduction fluxes of water, carbon dioxide, chlorine, and potassium. Geochemistry Geophysics Geosystems 4, 8905, doi:10.1029/2002GC000392.
John T., Scherer E.E., Haase K. and Schenk V. (2004) Trace element fractionation during fluid-induced eclogitization in a subducting slab: trace element and Lu-Hf-Sm-Nd isotope systematics. Earth Planet. Sci. Lett. 227, 441-456.
Kessel R., Schmidt M.W., Ulmer P. and Pettke T. (2005) Trace element signature of subduction-zone fluids, melts and supercritical liquids at 120-180 km depth. Nature 437, 724-727.
Li S.G., Xiao Y.L., Liu D.L., Chen Y.Z., Ge N.J., Zhang Z.Q., Sun S.-s., Cong B.L., Zhang R.Y., Hart S.R. and Wang S.S. (1993) Collision of the North China and Yangtse Blocks and formation of coesite-bearing eclogites: Timing and processes. Chem. Geol. 109, 89-111.
Li S.G., Wang S.S., Chen Y.Z., Liu D.L., Qiu J., Zhou H.X. and Zhang Z.M. (1994) Excess argon in phengite from eclogite: Evidence from dating of eclogite minerals by Sm-Nd, Rb-Sr and 40Ar/39Ar methods. Chem. Geol. 112, 343-350.
Li S.G., Jagoutz E., Lo C.-H., Chen Y.Z., Li Q.L. and Xiao Y.L. (1999) Sm/Nd, Rb/Sr, and 40Ar/39Ar isotopic systematics of the ultrahigh-pressure metamorphic rocks in the Dabie-Sulu belt, Central China: A retrospective view. Intern. Geol. Rev. 41, 1114-1124.
Li S.G., Jagoutz E., Chen Y.Z. and Li Q.L. (2000) Sm-Nd and Rb-Sr isotopic chronology and cooling history of ultrahigh pressure metamorphic rocks and their country rocks at Shuanghe in the Dabie Mountains, Central China. Geochim. Cosmochim. Acta 64, 1077-1093.
Li X.-P., Zheng Y.-F., Wu Y.-B., Chen F.K., Gong B. and Li Y.-L. (2004) Low-T eclogite in the Dabie terrane of China: Petrological and isotopic constraints on fluid activity and radiometric dating. Contrib. Mineral. Petrol. 148, 443-470.
Li Q.L., Li S.G., Hou Z.H., Hong J.A. and Yang W. (2005) A combined study of SHRIMP U-Pb dating, trace element and mineral inclusions on high-pressure metamorphic overgrowth zircon in eclogite from Qinglongshan in the Sulu terrane. Chinese Sci. Bull. 50, 5459-5465.
Liu L., Sun Y., Xiao P.X., Che Z.C., Luo J.H., Chen D.L., Wang Y., Zhang A.D., Chen L. and Wang Y.H. (2002) Discovery of ultrahigh-pressure magnesite-bearing garnet iherzolite (>3.8 GPa) in the Altyn Tagh, Northwest China. Chinese Sci. Bull. 47, 881-886.
Liu F.L. and Xu Z.Q. (2004) Fluid inclusions hidden in coesite-bearing zircons in ultrahigh-pressure metamorphic rocks from southwestern Sulu terrane in eastern China. Chinese Sci. Bull. 49, 396-404.
Liu F.L., Xu Z.Q. and Xue H.M. (2004a) Tracing the protolith, UHP metamorphism, and exhumation ages of orthogneiss from the SW Sulu terrane (eastern China): SHRIMP U-Pb dating of mineral inclusion-bearing zircons. Lithos 78, 411-429.
Liu F.L., Xu Z.Q., Liou J.G. and Song B. (2004b) SHRIMP U-Pb ages of ultrahigh-pressure and retrograde metamorphism of gneisses, south-western Sulu terrane, eastern China. J. Metamorph. Geol. 22, 315-326.
Liu F.L., Gerdes A., Liou J.G., Xue H.M. and Liang F.H. (2006a) SHRIMP U-Pb zircon dating from Sulu-Dabie dolomitic marble, eastern China: constraints on prograde, ultrahigh-pressure and retrograde metamorphic ages. J. Metamorph. Geol. 24, 569-589.
Liu D.Y., Jian P., Kröner A. and Xu S.T. (2006b) Dating of prograde metamorphic events deciphered from episodic zircon growth in rocks of the Dabie-Sulu UHP complex, China. Earth Planet. Sci. Lett. 250, 650-666.
Liu X.W., Jin Z.M. and Green II H.W. (2007a) Clinoenstatite exsolution in diopsidic augite of Dabieshan: Garnet peridotite from depth of 300 km. Am. Mineral. 92, 546-552.
Liu L., Zhang J.F., Green II H.W. Jin Z.M. and Bozhilov K.N. (2007b) Evidence of former stishovite in metamorphosed sediments, implying subduction to > 350 km. Earth Planet. Sci. Lett. 263, 180-191.
Liu F.L., Gerdes A., Zeng L.S. and Xue H.M. (2008) SHRIMP U-Pb dating, trace element and Lu-Hf isotope system of coesite-bearing zircon from amphibolite in SW Sulu UHP terrane, eastern China. Geochim. Cosmochim. Acta 72, 2973-3000.
Malaspina N., Hermann J., Scambelluri M. and Compagnoni R. (2006a) Polyphase inclusions in garnet-orthopyroxenite (Dabie Shan, China) as monitors for metasomatism and fluid-related trace element transfer in subduction zone peridotite. Earth Planet. Sci. Lett. 249, 173-187.
Malaspina N., Hermann J., Scambelluri M. and Compagnoni R. (2006b) Multistage metasomatism in ultrahigh-pressure mafic rocks from the North Dabie Complex (China). Lithos 90, 19-42.
Meng D.W., Wu X.L., Fan X.Y., Meng X., Zheng J.P. and Mason R. (2009) Submicron-sized fluid inclusions and distribution of hydrous components in jadeite, quartz and symplectite-forming minerals from UHP jadeite-quartzite in the Dabie Mountains, China: TEM and FTIR investigation. Applied Geochem. 24, 517-526
Ni P., Zhu X., Wang R.C., Shen K., Zhang Z.M., Qiu J.S. and Huang J.P. (2008) Constraining ultrahigh-pressure (UHP) metamorphism and titanium ore formation from an infrared microthermometric study of fluid inclusions in rutile from Donghai UHP eclogites, eastern China. Geol. Soc. Am. Bull. 120, 1296-1304.
Okay A.I., Xu S.T. and Sengor A.M.C. (1989) Coesite from the Dabie Shan eclogites, central China. Eur. J. Mineral. 1, 595-598.
Peacock S.M. (1990) Fluid processes in subduction zones. Science 248, 329-337.
Proyer A. (2003) The preservation of high-pressure rocks during exhumation: metagranites and metapelites. Lithos 70, 183-194.
Rumble D. and Yui T.-F. (1998) The Qinglongshan oxygen and hydrogen isotope anomaly near Donghai in Jiangsu province, China. Geochim. Cosmochim. Acta 62, 3307-3321.
Rumble D., Wang Q.C. and Zhang R.Y. (2000) Stable isotope geochemistry of marbles from the coesite UHP terrains of Dabieshan and Sulu, China. Lithos 52, 79-95.
Rumble D., Liou J.G and Jahn B.-m. (2003) Continental crust subduction and ultrahigh pressure metamorphism. Treatise on Geochemistry 3, 293-319.
Scambelluri M. and Philippot P. (2001) Deep fluids in subduction zones. Lithos 55, 213-227 .
Scambelluri M., Bottazzi P., Trommsdirff V., Vannucci R., Hermann J., Gomez-Pugnaire M.T. and Vizcaino V.L.-S. (2001) Incompatible element-rich fluids released by antigorite breakdown in deeply subducted mantle. Earth Planet. Sci. Lett. 192, 457-470.
Schmidt M.W. and Poli S. (1998) Experimentally based water budgets for dehydrating slabs and consequences for arc magma generation. Earth Planet. Sci. Lett. 163, 361-379.
Sheng Y.M., Xia Q.K., Yang X.Z., Hao Y.T. (2007) H2O contents and D/H ratios of nominally anhydrous minerals from ultrahigh-pressure eclogites of the Dabie orogen, eastern China. Geochim. Cosmochim. Acta 71, 2079-2103.
Smith D.C. (1984) Coesite in clinopyroxene in the Caledonides and its implications for geodynamics. Nature 310, 641-644.
Sobolev N.V. and Shatsky V.S. (1990) Diamond inclusions in garnets from metamorphic rocks; a new environment of diamond formation. Nature 343, 742-746.
Song S.G., Zhang L.F., Chen J., Liou J.G. and Niu Y.L. (2005) Sodic amphibole exsolutions in garnet from garnet-peridotite, North Qaidam UHPM belt, NW China; implications for ultradeep-origin and hydroxyl defects in mantle garnets. Am. Mineral. 90, 814-820.
Spandler C., Hermann J., Arculus R. and Mavrogenes J. (2004) Geochemical heterogeneity and element mobility in deeply subducted oceanic crust: insights from high-pressure mafic rocks from New Caledonia. Chem. Geol. 206, 21-42.
Su W., You Z.D. and Cong B.L. (2002) Cluster of water molecules in garnet from ultrahigh-pressure eclogite. Geology 30, 611-614.
Tang H.-F., Liu C.-Q., Nakai S.-i. and Orihashi Y. (2007) Geochemistry of eclogites from the Dabie-Sulu terrane, eastern China: New insights into protoliths and trace element behavior during UHP metamorphism. Lithos 95, 441-457.
Tang J., Zheng Y.-F., Wu Y.-B., Gong B., Zha X.P. and Liu X.M. (2008a) Zircon U-Pb age and geochemical constraints on the tectonic affinity of the Jiaodong terrane in the Sulu orogen, China. Precambr. Res. 161, 389-418.
Tang J., Zheng Y.-F., Gong B., Wu Y.-B., Gao T.-S., Yuan H.L. and Wu F.-Y. (2008b) Extreme oxygen isotope signature of meteoric water in magmatic zircon from metagranite in the Sulu orogen, China: implications for Neoproterozoic rift magmatism. Geochim. Cosmochim. Acta 72, 3139-3169.
Ulmer P. and Trommsdorff V. (1995) Serpentine stability to mantle depths and subduction-related magmatism. Science 268, 858-861.
Valley J.W., Lackey J.S., Cavosie A.J., Clechenko C.C., Spicuzza M.J., Basei M.A.S., Bindeman I.N., Ferreira V.P., Sial A.N., King E.M., Peck W.H., Sinha A.K. and Wei C.S. (2005) 4.4 billion years of crustal maturation: oxygen isotope ratios of magmatic zircon. Contrib. Mineral. Petrol. 150, 561-580.
Vallis F. and Scambelluri M. (1996) Redistribution of high-pressure fluids during retrograde metamorphism of eclogite-facies (Voltri Massif, Italian Western Alps). Lithos 39, 81-92.
Volkova N.I., Frenkel A.E., Budanov V.I. and Lepezin G.G. (2004) Geochemical signatures for eclogite protolith from the Maksyutov Complex, South Urals. J. Asian Earth Sci. 23, 745-759.
Wan Y.S., Li R.W., Wilde S.A., Liu D.Y., Chen Z.Y., Yan L.L., Song T.R. and Yin X.Y. (2005) UHP metamorphism and exhumation of the Dabie Orogen, China: Evidence from SHRIMP dating of zircon and monazite from a UHP granitic gneiss cobble from the Hefei Basin. Geochim. Cosmochim. Acta 69, 4333-4348.
Wang X.M., Liou J.G. and Mao H.K. (1989) Coesite-bearing from the Dabie Mountains in central China. Geology 17, 1085-1088.
Wang X.M., Zhang R.Y. and Liou J.G. (1995) UHPM terrane in east central China. In: Ultrahigh Pressure Metamorphism (eds. Coleman R. and Wang X.M.). Cambridge University Press, Cambridge, p.356-390.
Wu X.L., Meng D.W. and Han Y.J. (2004) A TEM study on fluid inclusions in coesite-bearing jadeite quartzite in Shuanghe in the Dabie Mountains. Acta Geol. Sin. 78, 121-124.
Wu Y.-B., Zheng Y.-F., Zhao Z.-F., Gong B., Liu X.M. and Wu F.-Y. (2006) U-Pb, Hf and O isotope evidence for two episodes of fluid-assisted zircon growth in marble-hosted eclogites from the Dabie orogen. Geochim. Cosmochim. Acta 70, 3743-3761.
Wu Y.-B., Gao S., Zhang H.-F., Yang S. H., Liu X.-C., Jiao W.-F., Liu Y.-S., Yuan H.-L., Gong H.-J. and He M.C. (2009) U-Pb age, trace-element, and Hf-isotope compositions of zircon in a quartz vein from eclogite in the western Dabie Mountains: Constraints on fluid flow during early exhumation of ultra high-pressure rocks. Am. Mineral. 94, 303-312.
Xia Q.-X., Zheng Y.-F. and Zhou L.-G. (2008) Dehydration and melting during continental collision: constraints from element and isotope geochemistry of low-T/UHP granitic gneiss in the Dabie orogen. Chem. Geol. 247, 36-65.
Xia Q.-X., Zheng Y.-F., Yuan H.L. and Wu F.-Y. (2009) Contrasting Lu-Hf and U-Th-Pb isotope systematics between metamorphic growth and recrystallization of zircon from eclogite-facies metagranite in the Dabie orogen, China. Lithos 112, 477-496.
Xia Q.-X., Zheng Y.-F. and Hu Z.-C. (2010) Trace elements in zircon and coexisting minerals from low-T/UHP metagranite in the Dabie orogen: implications for fluid regime during continental subduction-zone metamorphism. Lithos 114, 385-413.
Xie Z., Zheng Y.-F., Jahn B.-m., Ballevre M., Chen J.F., Gautier P., Gao T.-S., Gong B. and Zhou J.-B. (2004) Sm-Nd and Rb-Sr dating for pyroxene-garnetite from North Dabie in east-central China: problem of isotope disequilibrium due to retrograde metamorphism. Chem. Geol. 206, 137-158.
Xie L.-W., Zhang Y.-B., Zhang H.-H., Sun J.-F. and Wu F.-Y. (2008) In situ simultaneous determination of trace elements, U-Pb and Lu-Hf isotopes in zircon and baddeleyite. Chinese Sci. Bull. 53, 1565-1573.
Xu S.T., Okay A.I., Ji S.Y., Sengor A.M.C., Su W., Liu Y.C. and Jiang L.L. (1992) Diamond from the Dabie Shan metamorphic rocks and its implication for tectonic setting. Science 256, 80-82.
Xu Z.Q., Zeng L.S., Liu F.L., Yang J.S., Zhang Z.M., McWilliams M. and Liou J.G. (2006) Polyphase subduction and exhumation of the Sulu high-pressure-ultrahigh-pressure metamorphic terrane. Geol. Soc. Am. Spec. Paper 403, 93-113.
Yang J.S., Xu Z.Q., Song S.G., Zhang X., Wu C., Shi R., Li H. and Brunel M. (2001) Discovery of coesite in the North Qaidam Early Paleozoic ultrahigh-pressure metamorphic belt, NW China. C.R. Acad. Sci. Paris (Earth Planet. Sci.) 333, 719-724.
Yang J.S., Xu Z.Q., Dobrzhinetskaya L.F., Green II H.W., Pei X., Shi R., Wu C., Wooden J.L., Zhang J., Wan Y. and Li H. (2003) Discovery of metamorphic diamonds in Central China; an indication of a >4000 km-long-zone of deep subduction resulting from multiple continental collisions. Terra Nova 15, 370-379.
Yardley B., Gleeson S., Bruce S. and Banks D. (2000) Origin of retrograde fluids in metamorphic rocks. J. Geochem. Explor. 69-70, 281-285.
Ye K., Cong B.L. and Ye D.N. (2000) The possible subduction of continental material to depths greater than 200 km. Nature 407, 734-736.
Yuan H.L., Gao S., Rudnick R.L., Jin Z.M., Liu Y.S., Puchtel I.S., Walker R.J. and Yu R.D. (2007) Re-Os evidence for the age and origin of peridotites from the Dabie-Sulu ultrahigh pressure metamorphic belt, China. Chem. Geol. 236, 323-338.
Yuan H.L., Gao S., Dai M.N., Zong C.L., Günther D., Fontaine G.H., Liu X.M., Diwu C.R. (2008) Simultaneous determinations of U-Pb age, Hf isotopes and trace element compositions of zircon by excimer laser-ablation quadrupole and multiple-collector ICP-MS. Chem. Geol. 247, 100-118.
Yui T.-F., Rumble D. and Lo C.-H. (1995) Unusually low δ18O ultra-high-pressure metamorphic rocks from the Sulu Terrane, eastern China. Geochim. Cosmochim. Acta 59, 2859-2864.
Zhang L.F., Ellis D.J. and Jiang W.B. (2002) Ultrahigh pressure metamorphism in western Tianshan, China, part I; evidences from the inclusion of coesite pseudomorphs in garnet and quartz exsolution lamellae in omphacite in eclogites. Am. Mineral. 87, 853-860.
Zhang Z.M., Shen K., Sun W.D., Liu Y.S., Liou J.G, Shi C. and Wang J.L. (2008) Fluids in deeply subducted continental crust: petrology, mineral chemistry and fluid inclusion of UHP metamorphic veins from the Sulu orogen, eastern China. Geochim. Cosmochim. Acta 72, 3200-3228.
Zhang R.Y., Liou J.G. and Ernst W.G. (2009a) The Dabie-Sulu continental collision zone: A comprehensive review. Gondwana Res. 16, 1-26.
Zhang R.Y., Liou J.G., Zheng J.P., Griffin W.L., Yang Y.-H. and Jahn B.-m. (2009b) Petrogenesis of eclogites enclosed in mantle-derived peridotites from the Sulu UHP terrane: constraints from trace elements in minerals and Hf isotopes in zircon. Lithos 109, 176-192.
Zhao Z.-F., Zheng Y.-F., Gao T.-S., Wu Y.-B., Chen B., Chen F.K. and Wu F.-Y. (2006) Isotopic constraints on age and duration of fluid-assisted high-pressure eclogite-facies recrystallization during exhumation of deeply subducted continental crust in the Sulu orogen. J. Metamorph. Geol. 24, 687-702.
Zhao Z.-F., Zheng Y.-F., Chen R.-X., Xia Q.-X. and Wu Y.-B. (2007) Element mobility in mafic and felsic ultrahigh-pressure metamorphic rocks during continental collision. Geochim. Cosmochim. Acta 71, 5244-5266.
Zheng Y.-F., Fu B., Gong B. and Li S.G. (1996) Extreme 18O depletion in eclogite from the Su-Lu terrane in East China. Eur. J. Mineral. 8, 317-323.
Zheng Y.-F., Fu B., Li Y.-L., Xiao Y.L. and Li S.G. (1998) Oxygen and hydrogen isotope geochemistry of ultrahigh-pressure eclogites from the Dabie Mountains and Sulu terrane. Earth Planet. Sci. Lett. 155, 113-129.
Zheng Y.-F., Fu B., Xiao Y.L, Li Y.-L. and Gong B. (1999) Hydrogen and oxygen isotope evidence for fluid-rock interactions in the stages of pre- and post-UHP metamorphism in the Dabie Mountains. Lithos 46, 677-693.
Zheng Y.-F., Wang Z.-R., Li S.G. and Zhao Z.-F. (2002) Oxygen isotope equilibrium between eclogite minerals and its constraint on mineral Sm-Nd chronometer. Geochim. Cosmochim. Acta 66, 625-634.
Zheng Y.-F., Fu B., Gong B. and Li L. (2003a) Stable isotope geochemistry of ultrahigh pressure metamorphic rocks from the Dabie-Sulu orogen in China: implications for geodynamics and fluid regime. Earth Sci. Rev. 62, 105-161.
Zheng Y.-F., Zhao Z.-F., Li S.G. and Gong B. (2003b) Oxygen isotope equilibrium ultrahigh-pressure metamorphic minerals and its constraints on Sm-Nd and Rb-Sr chronometers. Geol. Soc. Spec. Publ. 220, 93-117.
Zheng Y.-F., Wu Y.-B., Chen F.K., Gong B., Li L. and Zhao Z.-F. (2004) Zircon U-Pb and oxygen isotope evidence for a large-scale 18O depletion event in igneous rocks during the Neoproterozoic. Geochim. Cosmochim. Acta 68, 4145-4165.
Zheng Y.-F., Wu Y.-B., Zhao Z.-F., Zhang S.-B., Xu P. and Wu F.-Y. (2005) Metamorphic effect on zircon Lu-Hf and U-Pb isotope systems in ultrahigh-pressure metagranite and metabasite. Earth Planet Sci. Lett. 240, 378-400.
Zheng Y.-F., Wu Y.-B., Gong B., Chen R.-X, Tang J. and Zhao Z.-F. (2007a) Tectonic driving of Neoproterozoic glaciations: Evidence from extreme oxygen isotope signature of meteoric water in granite. Earth Planet. Sci. Lett. 256, 196-210.
Zheng Y.-F., Gao T.-S., Wu Y.-B. and Gong B. (2007b) Fluid flow during exhumation of deeply subducted continental crust: Zircon U-Pb age and O isotope studies of quartz vein in eclogite. J. Metamorph. Geol. 25, 267-283.
Zheng Y.-F. (2008) A perspective view on ultrahigh-pressure metamorphism and continental collision in the Dabie-Sulu orogenic belt. Chinese Sci. Bull. 53, 3081-3104.
Zheng J.P., Sun M., Griffin W.L., Zhou M.F. and Zhao G.C. (2008) Age and geochemistry of contrasting peridotite types in the Dabie UHP belt, eastern China: petrogenetic and geodynamic implications. Chem. Geol. 247, 282-304.
Zheng Y.-F. (2009a) 25 years of continental deep subduction. Chinese Sci. Bull. 54, 4266-4270.
Zheng Y.-F. (2009b) Fluid regime in continental subduction zones: petrological insights from ultrahigh-pressure metamorphic rocks. J. Geol. Soc. 166, 763-782.
Zheng Y.-F., Chen R.-X. and Zhao Z.-F. (2009a) Chemical geodynamics of continental subduction-zone metamorphism: Insights from studies of the Chinese Continental Scientific Drilling (CCSD) core samples. Tectonophysics 475, 327-358.
Zheng L., Zhi X.C. and Reisberg L. (2009b) Re-Os systematics of the Raobazhai peridotite massifs from the Dabie orogenic zone, eastern China. Chem. Geol. 268, 1-14.
Zheng Y.-F., Ye K. and Zhang L.F. (2009c) Developing the plate tectonics from oceanic subduction to continental collision. Chinese Sci. Bull. 54, 2549-2555.
Zindler A. and Hart S.R. (1986) Chemical geodynamics. Ann. Rev. Earth Planet. Sci. 14, 493-571.
Figure Captions
Figure 1. Frequency histogram of countries publishing the most cited 100 papers in ultrahigh pressure metamorphism and continental deep subduction (after Zheng, 2009a).
Figure 2. Histograms of SHRIMP U-Pb ages for zircon from UHP metamorphic rocks in the Dabie-Sulu orogenic belt (after Zheng et al., 2009a). (a) Dates for coesite-bearing domain of metamorphic zircons, and (b) dates for metamorphic zircons without corresponding identification of coesite inclusions in the dating domain.
Figure 3. Comparison of oxygen isotope compositions for the Dabie-Sulu UHP eclogites with the other eclogites in the world (revised after Zheng et al., 2003a).
Figure 4. Schematic diagram showing timescales of UHP/HP metamorphism in the Dabie-Sulu orogenic belt due to continental subduction to and exhumation from mantle depths (after Zheng, 2008).
Figure 5. The relationship between water concentration and hydrogen isotope composition of omphacite and garnet from UHP eclogite in the main hole of CCSD, the Sulu orogen (data after Chen et al., 2007a). The decrease in total water concentration is associated with the increase in δD values, pointing to the preferential loss of D-depleted molecular water during exhumation.
Figure 6. Zircon Lu-Hf isotopic relationship between metamorphic domains of different origins for UHP eclogite and granitic gneiss from the Dabie orogen (revised after Zheng et al., 2005). While metamorphically grown zircon is characterized by decreased 176Lu/177Hf ratios but increased 176Hf/177Hf isotope ratios, metamorphically recrystallized zircon remains almost unchanged in both 176Lu/177Hf and 176Hf/177Hf isotope ratios.