Petrology and geochronology of ultrahigh-pressure granitic gneiss from South Dulan, North Qaidam belt, NW China

abstract An integrated study including petrography, mineral chemistry, metamorphic P–T path modelling, and zircon U–Pb dating was conducted on a granitic gneiss and enclosed eclogite from South Dulan, North Qaidam UHP (ultrahigh-pressure) belt. The result shows that the granitic gneiss underwent a clockwise P–T path with a peak-P stage at 655–745°C, 30–34 kbar, and a subsequent peak-T stage at 815–870°C, 14–18 kbar, which is similar to the P–T estimates reported for coesite-bearing continental-type eclogites in this region. The enclosed eclogite resembles an olivine–pyroxene-rich cumulate in Qaidam block. It has a similar prograde P–T path with the country gneiss and experienced a peak-P stage of 682–748°C at 27–34 kbar. Zircon U–Pb dating yields an eclogite-facies metamorphic age of 447 ± 2 Ma for the granitic gneiss and 445 ± 6 Ma for the enclosed eclogite. These ages agree with metamorphic ages obtained from paragneisses (427–439 Ma), coesite-bearing continental-type eclogites (430–451 Ma), and UHPM (ultrahigh-pressure metamorphic) oceanic crust–mantle sequence (440–445 Ma) from South Dulan, as well as UHP eclogites, garnet peridotite, and gneisses from other units (460–420 Ma) within this belt reported by others. Similar metamorphic ages as well as P–T evolution documented in gneisses and intercalated eclogites imply that both rocks experienced a coeval UHP event. Summarizing all the published geochronology data, we argue that the North Qaidam UHP belt was mainly formed by continental deep subduction at ~460 to ~420 Ma. The UHPM oceanic crust-mantle sequence in South Dulan may represent oceanic lithosphere in the transition zone between oceanic and continental crust, which was dragged upward by the exhumed continental rocks after break-off of the dense oceanic crust.

[1]  Jiangang Fu,et al.  Geochemistry, zircon U-Pb geochronology and Hf isotopes of granitic rocks in the Xitieshan area, North Qaidam, Northwest China: Implications for Neoproterozoic geodynamic evolutions of North Qaidam , 2015 .

[2]  A. Christy,et al.  Trace element behavior and P–T–t evolution during partial melting of exhumed eclogite in the North Qaidam UHPM belt (NW China): implications for adakite genesis , 2015 .

[3]  Y. Niu,et al.  Post-collisional magmatism: Consequences of UHPM terrane exhumation and orogen collapse, N. Qaidam UHPM belt, NW China , 2014 .

[4]  Sheng‐yao Yu,et al.  Paleozoic HP granulite-facies metamorphism and anatexis in the Dulan area of the North Qaidam UHP terrane, western China: Constraints from petrology, zircon U–Pb and amphibole Ar–Ar geochronology , 2014 .

[5]  Y. Niu,et al.  Continental orogenesis from ocean subduction, continent collision/subduction, to orogen collapse, and orogen recycling: The example of the North Qaidam UHPM belt, NW China , 2014 .

[6]  J. Gilotti,et al.  Zircon captures exhumation of an ultrahigh-pressure terrane, North-East Greenland Caledonides , 2014 .

[7]  D. Rubatto,et al.  Subduction of Continental Crust to Mantle Depth: Geochemistry of Ultrahigh-Pressure Rocks , 2014 .

[8]  Xilin Zhao,et al.  The Grenvillian orogeny in the Altun–Qilian–North Qaidam mountain belts of northern Tibet Plateau: Constraints from geochemical and zircon U–Pb age and Hf isotopic study of magmatic rocks , 2013 .

[9]  J. Hermann,et al.  Polyphase inclusions in the Shuanghe UHP eclogites formed by subsolidus transformation and incipient melting during exhumation of deeply subducted crust , 2013 .

[10]  Sheng‐yao Yu,et al.  Geochemistry, zircon UPb geochronology and LuHf isotopic composition of eclogites and their host gneisses in the Dulan area, North Qaidam UHP terrane: New evidence for deep continental subduction , 2013 .

[11]  A. Christy,et al.  From oceanic subduction to continental collision: An overview of HP-UHP metamorphic rocks in the North Qaidam UHP belt, NW China , 2013 .

[12]  W. Griffin,et al.  Decoupling of U–Pb and Lu–Hf isotopes and trace elements in zircon from the UHP North Qaidam orogen, NE Tibet (China): Tracing the deep subduction of continental blocks , 2012 .

[13]  Xian‐Hua Li,et al.  Grenville-age orogenesis in the Qaidam-Qilian block: The link between South China and Tarim , 2012 .

[14]  Yong‐Fei Zheng.  Metamorphic chemical geodynamics in continental subduction zones , 2012 .

[15]  Xian‐Hua Li,et al.  First record and timing of UHP metamorphism from zircon in the Xitieshan terrane: Implications for the evolution of the entire North Qaidam metamorphic belt , 2012 .

[16]  C. Spiers,et al.  A polyphase metamorphic evolution for the Xitieshan paragneiss of the north Qaidam UHP metamorphic belt, western China: In-situ EMP monazite- and U-Pb zircon SHRIMP dating , 2012 .

[17]  Liang Liu,et al.  Felsic veins within UHP eclogite at xitieshan in North Qaidam, NW China: Partial melting during exhumation , 2012 .

[18]  R. Powell,et al.  Revised activity–composition models for clinopyroxene and amphibole , 2012 .

[19]  Sheng‐yao Yu,et al.  Geochemistry and zircon U–Pb ages of adakitic rocks from the Dulan area of the North Qaidam UHP terrane, north Tibet: Constraints on the timing and nature of regional tectonothermal events associated with collisional orogeny , 2012 .

[20]  Sheng‐yao Yu,et al.  Petrology and P–T path of high-pressure granulite from the Dulan area, North Qaidam Mountains, northwestern China , 2011 .

[21]  Shuguang Song,et al.  Petrology and SHRIMP U–Pb dating of Xitieshan eclogite, North Qaidam UHP metamorphic belt, NW China , 2011 .

[22]  W. Griffin,et al.  Zircons in the Shenglikou ultrahigh-pressure garnet peridotite massif and its country rocks from the North Qaidam terrane (western China): Meso-Neoproterozoic crust–mantle coupling and early Paleozoic convergent plate-margin processes , 2011 .

[23]  M. Key,et al.  HP/UHP metamorphic time of eclogite in the Xitieshan terrane,North Qaidam UHPM belt,NW China , 2011 .

[24]  Xian‐Hua Li,et al.  Tracing the 850-Ma continental flood basalts from a piece of subducted continental crust in the North Qaidam UHPM belt, NW China , 2010 .

[25]  C. Mattinson,et al.  U–Pb zircon geochronology of coesite‐bearing eclogites from the southern Dulan area of the North Qaidam UHP terrane, northwestern China: spatially and temporally extensive UHP metamorphism during continental subduction , 2010 .

[26]  P. Agard,et al.  Initial water budget: The key to detaching large volumes of eclogitized oceanic crust along the subduction channel? , 2010 .

[27]  Z. Jianxin,et al.  Two Contrasting Eclogite Types on the Northern Margin of the Qaidam Basin, Western China , 2002 .

[28]  W. Griffin,et al.  Evolution of the Luliangshan garnet-peridotites in the North Qaidam UHP belt, Northern Tibetan Plateau : constraints from Re-Os isotopes , 2010 .

[29]  A. Benisek,et al.  A ternary feldspar-mixing model based on calorimetric data: development and application , 2010 .

[30]  R. Powell,et al.  Using calculated chemical potential relationships to account for coronas around kyanite: an example from the Bohemian Massif , 2010 .

[31]  Donna L. Whitney,et al.  Abbreviations for names of rock-forming minerals , 2010 .

[32]  K. Bucher,et al.  Petrology of coesite‐bearing eclogite from Habutengsu Valley, western Tianshan, NW China and its tectonometamorphic implication , 2009 .

[33]  A. Christy,et al.  UHP metamorphic evolution of coesite-bearing eclogite from the Yuka terrane, North Qaidam UHPM belt, NW China , 2009 .

[34]  Y. Niu,et al.  UHP metamorphic evolution and SHRIMP geochronology of a coesite-bearing meta-ophiolitic gabbro in the North Qaidam, NW China , 2009 .

[35]  Liang Liu,et al.  Geochemistry and zircon U-Pb dating and its implications of the Yukahe HP/UHP terrane, the North Qaidam, NW China , 2009 .

[36]  D. Bird,et al.  Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China , 2009 .

[37]  W. Ernst,et al.  Tectonics and HP–UHP metamorphism of northern Tibet – Preface , 2009 .

[38]  W. Ernst,et al.  Ultrahigh-pressure minerals and metamorphic terranes – The view from China , 2009 .

[39]  H. Yang,et al.  U–Pb geochronology of paragneisses and metabasite in the Xitieshan area, north Qaidam Mountains, western China: Constraints on the exhumation of HP/UHP metamorphic rocks , 2009 .

[40]  Y. Niu,et al.  Two types of peridotite in North Qaidam UHPM belt and their tectonic implications for oceanic and continental subduction: A review , 2009 .

[41]  A. Yin,et al.  Metamorphic evolution, mineral chemistry and thermobarometry of orthogneiss hosting ultrahigh-pressure eclogites in the North Qaidam metamorphic belt, Western China , 2009 .

[42]  Qianghu Liu,et al.  An experimental study of dehydration melting of phengite-bearing eclogite at 1.5–3.0 GPa , 2009 .

[43]  R. Compagnoni,et al.  The P–T path of the ultra‐high pressure Lago Di Cignana and adjoining high‐pressure meta‐ophiolitic units: insights into the evolution of the subducting Tethyan slab , 2009 .

[44]  B. Cesare,et al.  A thermodynamic model for titanium and ferric iron solution in biotite , 2009 .

[45]  Jianxin Zhang,et al.  Coesite in eclogite from the North Qaidam Mountains and its implications , 2009 .

[46]  Li Di.  Formation mechanisms of the Yematan UHP terrane,the North Qaidam:constrains from zircon U-Pb dating , 2009 .

[47]  J. D. Connolly,et al.  Titanium in phengite: a geobarometer for high temperature eclogites , 2009 .

[48]  C. Groppo,et al.  Counterclockwise P–T evolution of the Aghil Range: Metamorphic record of an accretionary melange between Kunlun and Karakorum (SW Sinkiang, China) , 2008 .

[49]  Y. Niu,et al.  The subducted oceanic crust within continental-type UHP metamorphic belt in the North Qaidam, NW China: Evidence from petrology, geochemistry and geochronology , 2008 .

[50]  R. Powell,et al.  Ultrahigh‐pressure garnet peridotites from the devolatilization of sea‐floor hydrated ultramafic rocks , 2008 .

[51]  P. O'Brien,et al.  Garnet growth at high- and ultra-high pressure conditions and the effect of element fractionation on mineral modes and composition , 2008 .

[52]  Jianxin Zhang,et al.  Polyphase Tectonothermal History Recorded in Granulitized Gneisses from the North Qaidam HP/UHP Metamorphic Terrane, Western China: Evidence from Zircon U-Pb Geochronology , 2008 .

[53]  O. Vanderhaeghe,et al.  Mobility of trace elements and oxygen in zircon during metamorphism: Consequences for geochemical tracing , 2008 .

[54]  D. Günther,et al.  Simultaneous determinations of U–Pb age, Hf isotopes and trace element compositions of zircon by excimer laser-ablation quadrupole and multiple-collector ICP-MS , 2008 .

[55]  Chen Dan.  Zicon U-Pb dating of paragneiss interbed in the UHP eclogite from Yematan area the North Qaidam UHP terrane, NW China. , 2008 .

[56]  Liang Liu,et al.  In situ LA-ICP-MS zircon U-Pb age of ultrahigh-pressure eclogites in the Yukahe area, northern Qaidam Basin , 2007 .

[57]  R. Klemd,et al.  Mobilization of Ti Nb-Ta during subduction : Evidence from rutile-bearing dehydration segregations and veins hosted in eclogite, Tianshan, NW China , 2007 .

[58]  G. Gehrels,et al.  Early Paleozoic Tectonic and Thermomechanical Evolution of Ultrahigh-Pressure (UHP) Metamorphic Rocks in the Northern Tibetan Plateau, Northwest China , 2007 .

[59]  R. Powell,et al.  Progress relating to calculation of partial melting equilibria for metapelites , 2007 .

[60]  R. Schuster,et al.  Characterization of polymetamorphism in the Austroalpine basement east of the Tauern Window using garnet isopleth thermobarometry , 2006 .

[61]  C. Mattinson,et al.  Age and duration of eclogite-facies metamorphism, North Qaidam HP/UHP terrane, Western China , 2006, American Journal of Science.

[62]  M. Schmidt,et al.  Experimental evidence of decompression melting during exhumation of subducted continental crust , 2006 .

[63]  J. B. Thomas,et al.  Crystallization thermometers for zircon and rutile , 2006 .

[64]  Dunyi Liu,et al.  Evolution from Oceanic Subduction to Continental Collision: a Case Study from the Northern Tibetan Plateau Based on Geochemical and Geochronological Data , 2006 .

[65]  W. Carlson.  Rates of Fe, Mg, Mn, and Ca diffusion in garnet , 2006 .

[66]  Jingsui Yang,et al.  Two contrasting eclogite cooling histories, North Qaidam HP/UHP terrane, western China: Petrological and isotopic constraints , 2005 .

[67]  James A. D. Connolly,et al.  Computation of phase equilibria by linear programming: A tool for geodynamic modeling and its application to subduction zone decarbonation , 2005 .

[68]  Dunyi Liu,et al.  Geochronology of diamond-bearing zircons from garnet peridotite in the North Qaidam UHPM belt, Northern Tibetan Plateau: A record of complex histories from oceanic lithosphere subduction to continental collision , 2005 .

[69]  J. Chen,et al.  Sodic amphibole exsolutions in garnet from garnet-peridotite, North Qaidam UHPM belt, NW China: Implications for ultradeep-origin and hydroxyl defects in mantle garnets , 2005 .

[70]  E. Deloule,et al.  Two Ultrahigh-Pressure Metamorphic Events Recognized in the Central Orogenic Belt of China: Evidence from the U-Pb Dating of Coesite-Bearing Zircons , 2005 .

[71]  W. Ernst.  Alpine and Pacific styles of Phanerozoic mountain building: subduction‐zone petrogenesis of continental crust , 2005 .

[72]  Chen Dan.  Metamorphic evolution of the Yuka eclogite in the North Qaidam,NW China:evidences from the compositional zonation of garnet and reaction texture in the rock. , 2005 .

[73]  Y. Jingsui.  Subducted Continental Arc: Geochemical and Isotopic Evidence of Gneisses in the North Qaidam , 2005 .

[74]  Z. Jianxin,et al.  Eclogitic metapelites in the western segment of the north Qaidam Mountains: Evidence on “ in situ ” relationship between eclogite and its country rock , 2004 .

[75]  R. Powell,et al.  Spatially‐focussed melt formation in aluminous metapelites from Broken Hill, Australia , 2004 .

[76]  Y. Niu,et al.  Ultra-deep origin of garnet peridotite from the North Qaidam ultrahigh-pressure belt, Northern Tibetan Plateau, NW China , 2004 .

[77]  T. Evans.  A method for calculating effective bulk composition modification due to crystal fractionation in garnet‐bearing schist: implications for isopleth thermobarometry , 2004 .

[78]  A. Meibom,et al.  Zircon U-Pb SHRIMP dating of the Yematan batholith in Dulan, North Qaidam, NW China , 2004 .

[79]  E. Ravna,et al.  Geothermobarometry of UHP and HP eclogites and schists – an evaluation of equilibria among garnet–clinopyroxene–kyanite–phengite–coesite/quartz , 2004 .

[80]  M. Whitehouse,et al.  Trace element signature and U–Pb geochronology of eclogite-facies zircon, Bergen Arcs, Caledonides of W Norway , 2004 .

[81]  I. Katayama,et al.  Global UHP Metamorphism and Continental Subduction/Collision: The Himalayan Model , 2004 .

[82]  R. Powell,et al.  Calculated Phase Relations in High-Pressure Metapelites in the System NKFMASH (Na2O–K2O–FeO–MgO–Al2O3–SiO2–H2O) , 2004 .

[83]  Jingsui Yang,et al.  Petrology, geochemistry and isotopic ages of eclogites from the Dulan UHPM Terrane, the North Qaidam, NW China , 2003 .

[84]  R. Shi,et al.  Metamorphic evolution of the coesite‐bearing ultrahigh‐pressure terrane in the North Qaidam, Northern Tibet, NW China , 2003 .

[85]  R. Powell,et al.  Orthopyroxene–sillimanite–quartz assemblages: distribution, petrology, quantitative P–T–X constraints and P–T paths , 2003 .

[86]  J. Platt,et al.  Dating high-grade metamorphism—constraints from rare-earth elements in zircon and garnet , 2003 .

[87]  K. Ludwig.  User's Manual for Isoplot 3.00 - A Geochronological Toolkit for Microsoft Excel , 2003 .

[88]  T. Andersen.  Correction of common lead in U-Pb analyses that do not report 204Pb , 2002 .

[89]  T. Holland,et al.  Mixing properties of phengitic micas and revised garnet‐phengite thermobarometers , 2002 .

[90]  D. Nakamura.  Kinetics of decompressional reactions in eclogitic rocks – formation of plagioclase coronas around kyanite , 2002 .

[91]  D. Rubatto.  Zircon trace element geochemistry: partitioning with garnet and the link between U–Pb ages and metamorphism , 2002 .

[92]  R. Powell,et al.  The interpretation of reaction textures in Fe‐rich metapelitic granulites of the Musgrave Block, central Australia: constraints from mineral equilibria calculations in the system K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3 , 2002 .

[93]  R. Powell,et al.  Fractionation of bulk rock composition due to porphyroblast growth: effects on eclogite facies mineral equilibria, Pam Peninsula, New Caledonia , 2002 .

[94]  张建新,et al.  Two Contrasting Eclogite Types on the Northern Margin of the Qaidam Basin, Western China , 2002 .

[95]  Haibing Li,et al.  Discovery of coesite in the North Qaidam Early Palaeozoic ultrahigh pressure (UHP) metamorphic belt, NW China , 2001 .

[96]  Z. Jianxin,et al.  Ages and Compositions of the Precambrian High‐grade Basement of the Qilian Terrane and Its Adjacent Areas , 2001 .

[97]  R. Powell,et al.  Calculation of partial melting equilibria in the system Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O (NCKFMASH) , 2001 .

[98]  Worley,et al.  The effect of TiO2 and Fe2O3 on metapelitic assemblages at greenschist and amphibolite facies conditions: mineral equilibria calculations in the system K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3 , 2000 .

[99]  M. J. Holdaway.  Application of new experimental and garnet Margules data to the garnet-biotite geothermometer , 2000 .

[100]  Krogh Ravna.  The garnet–clinopyroxene Fe2+–Mg geothermometer: an updated calibration , 2000 .

[101]  Haibing Li,et al.  Discovery of eclogite at northern margin of Qaidam Basin, NW China , 1998 .

[102]  Roger Powell,et al.  An internally consistent thermodynamic data set for phases of petrological interest , 1998 .

[103]  Ian S. Williams,et al.  Pb, U and Th diffusion in natural zircon , 1997, Nature.

[104]  R. Powell,et al.  Thermodynamics of order-disorder in minerals: II. Symmetric formalism applied to solid solutions , 1996 .

[105]  S. Maruyama,et al.  Blueschists and Eclogites of the World and Their Exhumation , 1996 .

[106]  S. Chakraborty,et al.  Cation diffusion in aluminosilicate garnets: experimental determination in spessartine-almandine diffusion couples, evaluation of effective binary diffusion coefficients, and applications , 1992 .

[107]  R. Powell,et al.  A Compensated-Redlich-Kwong (CORK) equation for volumes and fugacities of CO2 and H2O in the range 1 bar to 50 kbar and 100–1600°C , 1991 .

[108]  T. Hoisch,et al.  Empirical calibration of six geobarometers for the mineral assemblage quartz+muscovite+biotite+plagioclase+garnet , 1990 .

[109]  F. Spear.  Metamorphic fractional crystallization and internal metasomatism by diffusional homogenization of zoned garnets , 1988 .

[110]  G. Droop,et al.  A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria , 1987, Mineralogical Magazine.

[111]  P. England,et al.  Pressure—Temperature—Time Paths of Regional Metamorphism II. Their Inference and Interpretation using Mineral Assemblages in Metamorphic Rocks , 1984 .

[112]  T. Green,et al.  FeMg partitioning between coexisting garnet and phengite at high pressure, and comments on a garnet-phengite geothermometer , 1982 .

[113]  R. Tracy.  Compositional zoning and inclusions in metamorphic minerals , 1982 .

[114]  B. Leake,et al.  Report. Nomenclature of Amphiboles: Report of the Subcommittee on Amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names , 1971, Mineralogical Magazine.

[115]  L. Hollister.  Garnet Zoning: An Interpretation Based on the Rayleigh Fractionation Model , 1966, Science.

[116]  T. Hor.  Thermodynamics of order-disorder in minerals : II . Symmetric formalism applied to solid solutions , 2022 .