Petrogenesis of Permian to Triassic granitoids from the East Kunlun orogenic belt: implications for crustal evolution during oceanic subduction and continental collision

ABSTRACT The study of Permian-Triassic granitoids, which widely occur within the East Kunlun Orogenic Belt (EKOB), is relevant for a better understanding of the evolution of the Paleo-Tethys Ocean and regional crustal evolution. This study focuses on the Permian-Triassic granitoids from the Nagengkangqieer region, east segment of EKOB. The Late Permian granodiorite (ca. 252 Ma) shows high-K calc-alkaline and metaluminous features with moderate SiO2 (63.31–67.04 wt.%), relatively high Mg# (48–52), and low Sr/Y ratios. The granodiorite is enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs) and shows enriched isotopic compositions (εNd (t) = −5.53 to −5.14, εHf (t) = −5.6 to −1.1). These geochemical characteristics imply that the Late Permian granodiorite was derived from a mixing source of mafic lower crust and mantle materials (<30%). The Middle Triassic porphyritic monzogranite (ca. 239 Ma) and monzogranite (ca. 239 Ma) are high-K calc-alkaline to shoshonitic and weak peraluminous with high SiO2 (70.58–76.54 wt.%) contents and low Mg# (19–36). They display relatively higher FeOT/MgO ratios, lower P2O5 contents, and more enriched isotopic compositions (εNd (t) = −7.87 to −6.71, εHf (t) = −13.7 to −1.2) than those of granodiorites. These findings indicate that the Triassic granites belong to fractionated granites derived from partial melting of the lower continental crust. In combination with the results of this study and the spatio-temporal distribution of regional magmatic, metamorphic, and sedimentary events, we conclude that Late Permian granodiorite formed in a subduction setting, whereas the Middle Triassic granites were formed in a syn-collision setting. Closing of the Paleo-Tethys Ocean occurred in the Middle Triassic (ca. 240 Ma). Additionally, only a small proportion of juvenile materials (<30%) was involved in magmatism and contributed to continental crustal growth during Late Permian subduction, whereas crustal reworking dominated regional magmatism and resulted in a higher crustal maturity.

[1]  J. Huizenga,et al.  Rare earth element enrichment in the ion-adsorption deposits associated granites at Mesozoic extensional tectonic setting in South China , 2021 .

[2]  Shucheng Tan,et al.  Late Permian-Middle Triassic intermediate-acid intrusive rocks in the Eastern Kunlun Orogenic Belt, NW China: Petrogenesis and implications for geodynamic evolution , 2021, International Geology Review.

[3]  Yong‐Fei Zheng,et al.  The production of granitic magmas through crustal anatexis at convergent plate boundaries , 2021 .

[4]  Wei Xin,et al.  Triassic granitoids in the East Kunlun Orogenic Belt, Northwestern China: magmatic source and implications for geodynamic evolution , 2020, International Geology Review.

[5]  Fengli Shao,et al.  Petrogenesis of the Triassic granitoids from the East Kunlun Orogenic Belt, NW China: Implications for continental crust growth from syn-collisional to post-collisional setting , 2020 .

[6]  Yayun Liang,et al.  Petrogenesis and tectonic significance of Late Triassic Baishiya granodiorite porphyries in the Dulan area, eastern segment of the East Kunlun Orogenic Belt, China , 2020, Geological Journal.

[7]  M. Santosh,et al.  Multi-stage crustal melting from Late Permian back-arc extension through Middle Triassic continental collision to Late Triassic post-collisional extension in the East Kunlun Orogen , 2020 .

[8]  Cin-Ty A. Lee,et al.  Evolution and maturation of the nascent Mariana arc , 2020 .

[9]  M. Santosh,et al.  Anisian granodiorites and mafic microgranular enclaves in the eastern Kunlun Orogen, NW China: Insights into closure of the eastern Paleo–Tethys , 2019, Geological Journal.

[10]  Zhao Cai-sheng,et al.  Origin of the Late Permian gabbros and Middle Triassic granodiorites and their mafic microgranular enclaves from the Eastern Kunlun Orogen Belt: Implications for the subduction of the Palaeo-Tethys Ocean and continent-continent collision , 2020 .

[11]  D. Wyman,et al.  Crustal maturation through chemical weathering and crustal recycling revealed by Hf–O–B isotopes , 2019, Earth and Planetary Science Letters.

[12]  Yan Liu,et al.  Late Permian back-arc extension of the eastern Paleo-Tethys Ocean: Evidence from the East Kunlun Orogen, Northern Tibetan Plateau , 2019, Lithos.

[13]  Z. Pang,et al.  Origin of the Late Permian gabbros and Middle Triassic granodiorites and their mafic microgranular enclaves from the Eastern Kunlun Orogen Belt: Implications for the subduction of the Palaeo‐Tethys Ocean and continent–continent collision , 2018, Geological Journal.

[14]  Huan Xu,et al.  Geological significance of the former Xiong’er Volcanic Belt on the southwestern margin of the North China Craton , 2018, Frontiers of Earth Science.

[15]  Xu Zhao,et al.  Multiple sources of the Early Mesozoic Gouli batholith, Eastern Kunlun Orogenic Belt, northern Tibetan Plateau: Linking continental crustal growth with oceanic subduction , 2017 .

[16]  Fengli Shao,et al.  Petrogenesis of Triassic granitoids in the East Kunlun Orogenic Belt, northern Tibetan Plateau and their tectonic implications. , 2017 .

[17]  Jun Deng,et al.  Petrogenesis of ca. 240 Ma intermediate and felsic intrusions in the Nan’getan: Implications for crust–mantle interaction and geodynamic process of the East Kunlun Orogen , 2017 .

[18]  Fu-guan Wu,et al.  Highly fractionated granites: Recognition and research , 2017, Science China Earth Sciences.

[19]  L. Chengjun,et al.  Provenance analysis and structural implications of Gequ Formation at the Buqingshan area in the eastern segment of the East Kunlun region , 2016 .

[20]  Deng Jinf.  Magmatic Arc and Ocean—Continent Transition:Discussion , 2015 .

[21]  B. Liu,et al.  Reworking of old continental lithosphere: an important crustal evolution mechanism in orogenic belts, as evidenced by Triassic I-type granitoids in the East Kunlun orogen, Northern Tibetan Plateau , 2014, Journal of the Geological Society.

[22]  G. Nowell,et al.  Geochemical constraints on the petrogenesis of granitoids in the East Kunlun Orogenic belt, northern Tibetan Plateau: Implications for continental crust growth through syn-collisional felsic magmatism , 2014 .

[23]  K. Schulmann,et al.  Petrogenesis and geochronology of a post-orogenic calc-alkaline magmatic association: the Zulova Pluton, Bohemian Massif , 2014 .

[24]  B. Liu,et al.  40Ar–39Ar age and geochemistry of subduction-related mafic dikes in northern Tibet, China: petrogenesis and tectonic implications , 2014 .

[25]  R. Rudnick,et al.  Composition of the Continental Crust , 2014 .

[26]  S. Zhong.  Geochemical characteristics of Harizha granite diorite-porphyry in East Kunlun and their geological implications , 2013 .

[27]  Shan Gao,et al.  Improved in situ Hf isotope ratio analysis of zircon using newly designed X skimmer cone and jet sample cone in combination with the addition of nitrogen by laser ablation multiple collector ICP-MS , 2012 .

[28]  Xiong Fu.  LA-ICP-MS zircon U-Pb dating,elements and Sr-Nd-Hf isotope geochemistry of the Early Mesozoic mafic dyke swarms in East Kunlun orogenic belt , 2011 .

[29]  H. Jian.  Zircon LA-ICP-MS U-Pb dating of Bairiqili gabbro pluton in East Kunlun orogenic belt and its geological significance , 2011 .

[30]  L. Yongsheng,et al.  Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS , 2010 .

[31]  P. Kelemen,et al.  Geochemistry and magmatic history of eclogites and ultramafic rocks from the Chinese continental scientific drill hole: Subduction and ultrahigh-pressure metamorphism of lower crustal cumulates , 2008 .

[32]  Guowei Zhang,et al.  Geochemistry and spatial distribution of late-Paleozoic mafic volcanic rocks in the surrounding areas of the Gonghe Basin: Implications for Majixueshan triple-junction and east Paleotethyan archipelagic ocean , 2007 .

[33]  Xiang Shu-yuan.  Some ideas of Precambrian geology in the East Kunlun, China , 2007 .

[34]  Zhu Yunhai,et al.  Lithological Characteristics of the Baishahe Formation to the South of Xiangride Town,Eastern Kunlun Mountains and Its Age Constrained from Zircon Pb-Pb Dating , 2006 .

[35]  R. Handler,et al.  40Ar/39Ar mineral ages from basement rocks in the Eastern Kunlun Mountains, NW China, and their tectonic implications , 2005 .

[36]  A. Glazner,et al.  Voluminous granitic magmas from common basaltic sources , 2005 .

[37]  Y. Neng.  Geochemical study on peraluminous granite from Jinshuikou in East Kunlun , 2005 .

[38]  W. McDonough,et al.  Petrology and geochemistry of spinel peridotite xenoliths from Hannuoba and Qixia, North China craton , 2004 .

[39]  Yong‐Fei Zheng,et al.  Genesis of zircon and its constraints on interpretation of U-Pb age , 2004 .

[40]  M. Marks,et al.  Crustal contamination of mafic magmas: evidence from a petrological, geochemical and Sr–Nd–Os–O isotopic study of the Proterozoic Isortoq dike swarm, South Greenland , 2004 .

[41]  Wang Guo-can.  Zircon SHRIMP ages of Precambrian metamorphic basement rocks and their tectonic significance in the eastern Kunlun Mountains, Qinghai Province, China , 2004 .

[42]  T. Feininger.  Igneous Rocks: A Classification and Glossary of Terms (Recommendations of the IUGS Subcommission on the Systematics of Igneous Rocks).Second edition. Edited by R.W. LeMaitre. Cambridge University Press, New York, N.Y., 2002, 236 + xvi pages. US$65 (ISBN 0–521–66215–X). , 2002 .

[43]  R. W. Le Maitre,et al.  Igneous Rocks: A Classification and Glossary of Terms , 2002 .

[44]  Li Chengdong.  Features and origin of mafic microgranular enclaves in the Yuegelu granite in the Eastern Kunlun , 2002 .

[45]  Calvin G. Barnes,et al.  A Geochemical Classification for Granitic Rocks , 2001 .

[46]  B. Chappell,et al.  Two contrasting granite types: 25 years later , 2001 .

[47]  Xianzhi Pei,et al.  Northernmost paleo-tethyan oceanic basin in Tibet: Geochronological evidence from40Ar/39Ar age dating of Dur’ngoi ophiolite , 2001 .

[48]  E. Hegner,et al.  High-potassium, calc-alkaline I-type plutonism in the European Variscides: northern Vosges (France) and northern Schwarzwald (Germany) , 2000 .

[49]  W. Griffin,et al.  The Hf isotope composition of cratonic mantle: LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites , 2000 .

[50]  A. P. Douce,et al.  Generation of metaluminous A-type granites by low-pressure melting of calc-alkaline granitoids , 1997 .

[51]  F. Albarède,et al.  Separation of Hf and Lu for high-precision isotope analysis of rock samples by magnetic sector-multiple collector ICP-MS , 1997 .

[52]  R. Rapp.  Amphibole-out phase boundary in partially melted metabasalt, its control over liquid fraction and composition, and source permeability , 1995 .

[53]  E. Watson,et al.  Dehydration melting of metabasalt at 8-32 kbar : Implications for continental growth and crust-mantle recycling , 1995 .

[54]  T. Green.  Significance of Nb/Ta as an indicator of geochemical processes in the crust-mantle system , 1995 .

[55]  E. Middlemost.  Naming materials in the magma/igneous rock system , 1994 .

[56]  W. S. Pitcher.  The nature and origin of granite , 1993 .

[57]  B. Chappell,et al.  I- and S-type granites in the Lachlan Fold Belt , 1992, Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

[58]  I. Moreno-Ventas,et al.  H-type (hybrid) granitoids: a proposed revision of the granite-type classification and nomenclature , 1991 .

[59]  A. Peccerillo,et al.  Geochemical and isotopic evidence for crystal fractionation, AFC and crustal anatexis in the genesis of the Rensen Plutonic Complex (Eastern Alps, Italy) , 1991 .

[60]  B. Weaver.  The origin of ocean island basalt end-member compositions: trace element and isotopic constraints , 1991 .

[61]  M. Drummond,et al.  Derivation of some modern arc magmas by melting of young subducted lithosphere , 1990, Nature.

[62]  P. Sylvester.  Post-Collisional Alkaline Granites , 1989, The Journal of Geology.

[63]  P. Piccoli,et al.  Tectonic discrimination of granitoids , 1989 .

[64]  W. McDonough,et al.  Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes , 1989, Geological Society, London, Special Publications.

[65]  J. Whalen,et al.  A-type granites: geochemical characteristics, discrimination and petrogenesis , 1987 .

[66]  R. Batchelor,et al.  Petrogenetic interpretation of granitoid rock series using multicationic parameters , 1985 .

[67]  S. Taylor,et al.  The continental crust: Its composition and evolution , 1985 .

[68]  A. Tindle,et al.  Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks , 1984 .

[69]  W. S. Pitcher.  Granite type and tectonic environment , 1983 .

[70]  S. Taylor,et al.  Geochemistry of eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey , 1976 .