Metamorphic Evolution and Tectonic Implications of the Granulitized Eclogites from the Luliangshan Terrane in the North Qaidam Ultrahigh Pressure Metamorphic Belt, NW China: New Constraints from Phase Equilibrium Modeling

Abstract

The granulitized eclogites from the Luliangshan terrane of the North Qaidam UHP metamorphic belt occur as lenses within pelitic gneisses and orthogneisses. Combined petrologic data and phase equilibrium modeling indicate a multi-stage metamorphic history of the granulitized eclogites: (1) an earlier eclogite facies metamorphism (P>18.5 kbar, T> 830 °C) is deduced from omphacite relics in the matrix and rare omphacite inclusions within garnet. The possible assemblage is garnet+omphacite+rutile+ quartz; (2) the early stage of high pressure granulite facies assemblages (garnet+clinopyroxene+ plagioclase+rutile+quartz+liquid) developed in the early decompression process has a P-T regime of 17.5 kbar and 852–858 °C, constrained by plagioclase and clinopyroxene inclusions in garnet. The late stage of high pressure granulite assemblages (garnet+clinopyroxene+amphibole+plagioclase+rutile+quartz+liquid) records an isothermal decompression process with the pressure successively declining from 17.5 to 14.7 kbar and to 11.3 kbar at 858 °C; (3) the later medium pressure granulite facies assemblage (garnet+ orthopyroxene+ clinopyroxene+amphibole+plagioclase+ilmenite+liquid+quartz) indicates a drop in pressure and rise in temperature at P-T conditions of 7.6–7.7 kbar and 878–883 °C; (4) retrogressive amphibolite facies stage, which is represented by amphibole+plagioclase kelyphitic rims around garnet, formed under conditions of <5 kbar and <650 °C. The preservation of medium pressure granulite facies assemblage and the garnet composition feature constrain a following isobaric cooling path during late exhumation. This process suggests a clockwise P-T path and indicates that the granulitized eclogites record a high grade “Barrovian” metamorphic overprint at the middle-lower crust during exhumation. The present data show that the Luliangshan terrane is a “hot” HP-UHP terrane.

Keywords

phase equilibrium modeling / granulitized eclogite / North Qaidam / Luliangshan terrane

References

[1] Beard J S, Lofgren G E. Dehydration Melting and Water- Saturated Melting of Basaltic and Andesitic Greenstones and Amphibolites at 1, 3, and 6.9 kb. Journal of Petrology, 1991, 32(2): 365-401.

[2] Cai J, Liu F L, Liu P H, . Metamorphic P-T Path and Tectonic Implications of Pelitic Granulites from the Daqingshan Complex of the Khondalite Belt, North China Craton. Precambrian Research, 2014, 241: 161-184.

[3] Cao Y T, Liu L, Chen D L, . Partial Melting during Exhumation of Paleozoic Retrograde Eclogite in North Qaidam, Western China. Journal of Asian Earth Sciences, 2017, 148: 223-240.

[4] Chen D L, Sun Y, Liu L, . 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. Acta Petrologica Sinica, 2005, 21(4): 1039-1048. (In Chinese with English Abstract)

[5] Chen X, Xu R K, Zheng Y Y, . Petrology and Geochemistry of High Niobium Eclogite in the North Qaidam Orogen, Western China: Implications for an Eclogite Facies Metamorphosed Island Arc Slice. Journal of Asian Earth Sciences, 2018, 164: 380-397.

[6] Cruciani G, Franceschelli M, Groppo C, . Metamorphic Evolution of Non-Equilibrated Granulitized Eclogite from Punta de Li Tulchi (Variscan Sardinia) Determined through Texturally Controlled Thermodynamic Modelling. Journal of Metamorphic Geology, 2012, 30(7): 667-685.

[7] Frost B R, Chacko T. The Granulite Uncertainty Principle: Limitations on Thermobarometry in Granulites. Journal of Geology, 1989, 97(4): 435-450.

[8] Green D H, Ringwood A E. An Experimental Investigation of the Gabbro to Eclogite Transformation and Its Petrological Applications. Geochimica et Cosmochimica Acta, 1967, 31(5): 767-833.

[9] Green E C R, White R W, Diener J F A, . Activity-Composition Relations for the Calculation of Partial Melting Equilibria in Metabasic Rocks. Journal of Metamorphic Geology, 2016, 34(9): 845-869.

[10] Groppo C, Lombardo B, Rolfo F, . Clockwise Exhumation Path of Granulitized Eclogites from the Ama Drime Range (Eastern Himalayas). Journal of Metamorphic Geology, 2007, 25(1): 51-75.

[11] Groppo C, Rolfo F, Liu Y C, . P-T Evolution of Elusive UHP Eclogites from the Luotian Dome (North Dabie Zone, China): How far can the Thermodynamic Modeling Lead Us?. Lithos, 2015, 226: 183-200.

[12] Harley S L. The Origins of Granulites: A Metamorphic Perspective. Geological Magazine, 1989, 126(3): 215-247.

[13] Hensen B J, Green D H. Experimental Study of the Stability of Cordierite and Garnet in Pelitic Compositions at High Pressures and Temperatures. Contributions to Mineralogy and Petrology, 1971, 33(4): 309-330.

[14] Holland T J B, Powell R. An Internally Consistent Thermodynamic Data Set for Phases of Petrological Interest. Journal of Metamorphic Geology, 1998, 16(3): 309-343.

[15] Holland T J B, Powell R. An Improved and Extended Internally Consistent Thermodynamic Dataset for Phases of Petrological Interest, Involving a New Equation of State for Solids. Journal of Metamorphic Geology, 2011, 29(3): 333-383.

[16] Holland T J B, Powell R. Activity-Composition Relations for Phases in Petrological Calculations: An Asymmetric Multicomponent Formulation. Contributions to Mineralogy and Petrology, 2003, 145(4): 492-501.

[17] Korhonen F J, Brown M, Clark C, . Osumilite-Melt Interactions in Ultrahigh Temperature Granulites: Phase Equilibria Modelling and Implications for the P-T-t Evolution of the Eastern Ghats Province, India. Journal of Metamorphic Geology, 2013, 31(8): 881-907.

[18] Korhonen F J, Powell R, Stout J H. Stability of Sapphirine+Quartz in the Oxidized Rocks of the Wilson Lake Terrane, Labrador: Calculated Equilibria in NCKFMASHTO. Journal of Metamorphic Geology, 2012, 30(1): 21-36.

[19] Korhonen F J, Saw A K, Clark C, . New Constraints on UHT Metamorphism in the Eastern Ghats Province through the Application of Phase Equilibria Modelling and in situ Geochronology. Gondwana Research, 2011, 20(4): 764-781.

[20] Leake B E, Woolley A R, Arps C E S, . Nomenclature of Amphiboles; Report of the Subcommittee on Amphiboles of the International Mineralogical Association Commission on New Minerals and Mineral Names. Mineralogical Magazine, 1997, 61(405): 295-310.

[21] Li X W, Wei C J. Phase Equilibria Modelling and Zircon Age Dating of Pelitic Granulites in Zhaojiayao, from the Jining Group of the Khondalite Belt, North China Craton. Journal of Metamorphic Geology, 2016, 34(6): 595-615.

[22] Li Y S, Zhang J X, Mostofa K M G, . Petrogenesis of Carbonatites in the Luliangshan Region, North Qaidam, Northern Tibet, China: Evidence for Recycling of Sedimentary Carbonate and Mantle Metasomatism within a Subduction Zone. Lithos, 2018, 322: 148-165.

[23] Liao X Y, Liu L, Wang Y W, . Multi-Stage Metamorphic Evolution of Retrograde Eclogite with a Granulite-Facies Overprint in the Zhaigen Area of the North Qinling Belt, China. Gondwana Research, 2016, 30: 79-96.

[24] Meng F C, Zhang J X. Contemporaneous of Early Palaeozoic Granite and High Temperature Metamorphism, North Qaidam Mountains, Western China. Acta Petrologica Sinica, 2008, 24(7): 1585-1594. (in Chinese with English Abstract)

[25] Morimoto N. Nomenclature of Pyroxenes. Mineralogy and Petrology, 1988, 39(1): 55-76.

[26] Morrissey L J, Hand M, Raimondo T, . Long-Lived High-T, Low-P Granulite Facies Metamorphism in the Arunta Region, Central Australia. Journal of Metamorphic Geology, 2014, 32(1): 25-47.

[27] Nakamura D, Hirajima T. Granulite-Facies Overprinting of Ultrahigh-Pressure Metamorphic Rocks, Northeastern Su-Lu Region, Eastern China. Journal of Petrology, 2000, 41(4): 563-582.

[28] O’Brien P J. Asymmetric Zoning Profiles in Garnet from HP-HT Granulite and Implications for Volume and Grain-Boundary Diffusion. Mineralogical Magazine, 1999, 63(2): 227-238.

[29] O’Brien P J. Garnet Zoning and Reaction Textures in Overprinted Eclogites, Bohemian Massif, European Variscides: A Record of Their Thermal History during Exhumation. Lithos, 1997, 41(1/2/3): 119-133.

[30] Powell R, Holland T J B. On Thermobarometry. Journal of Metamorphic Geology, 2008, 26(2): 155-179.

[31] Powell R, Holland T J B, Worley B. Calculating Phase Diagrams Involving Solid Solutions via Non-Linear Equations, with Examples Using THERMOCALC. Journal of Metamorphic Geology, 1998, 16(4): 577-588.

[32] Rapp R P, Shimizu N, Norman M D. Growth of Early Continental Crust by Partial Melting of Eclogite. Nature, 2003, 425(6958): 605-609.

[33] Ren Y F, Chen D L, Kelsey D E, . Metamorphic Evolution of a Newly Identified Mesoproterozoic Oceanic Slice in the Yuka Terrane and Its Implications for a Multi-Cyclic Orogenic History of the Metamorphic Evolution and Tectonic Implications of the Granulitized Eclogites from the Luliangshan Terrane 601 North Qaidam UHPM Belt. Journal of Metamorphic Geology, 2018, 36(4): 463-488.

[34] Ren Y F, Chen D L, Kelsey D E, . Gondwana Research, 2017, 42: 220-242.

[35] Rushmer T. Partial Melting of Two Amphibolites: Contrasting Experimental Results under Fluid-Absent Conditions. Contributions to Mineralogy and Petrology, 1991, 107(1): 41-59.

[36] Rushmer T. Experimental High-Pressure Granulites: Some Applications to Natural Mafic Xenolith Suites and Archean Granulite Terranes. Geology, 1993, 21(5): 411-414.

[37] Sen C, Dunn T. Dehydration Melting of a Basaltic Composition Amphibolite at 1.5 and 2.0 GPa: Implications for the Origin of Adakites. Contributions to Mineralogy and Petrology, 1994, 117(4): 394-409.

[38] Shimizu H, Tsunogae T, Santosh M, . Phase Equilibrium Modelling of Palaeoproterozoic Ultrahigh-Temperature Sapphirine Granulite from the Inner Mongolia Suture Zone, North China Craton: Implications for Counterclockwise P-T Path. Geological Journal, 2013, 48(5): 456-466.

[39] Song S G, Yang J S, Xu Z Q, . Metamorphic Evolution of the Coesite-Bearing Ultrahigh-Pressure Terrane in the North Qaidam, Northern Tibet, NW China. Journal of Metamorphic Geology, 2003, 21(6): 631-644.

[40] Song S G, Zhang L F, Niu Y L, . Evolution from Oceanic Subduction to Continental Collision: A Case Study from the Northern Tibetan Plateau Based on Geochemical and Geochronological Data. Journal of Petrology, 2006, 47(3): 435-455.

[41] Song S G, Niu Y L, Su L, . Continental Orogenesis from Ocean Subduction, Continent Collision/Subduction, to Orogen Collapse, and Orogen Recycling: The Example of the North Qaidam UHPM Belt, NW China. Earth-Science Reviews, 2014, 129: 59-84.

[42] Song S G, Su L, Li X H, . Grenville-Age Orogenesis in the Qaidam-Qilian Block: The Link between South China and Tarim. Precambrian Research, 2012, 220/(221): 9-22.

[43] Song S G, Su L, Li X H, . Tracing the 850-Ma Continental Flood Basalts from a Piece of Subducted Continental Crust in the North Qaidam UHPM Belt, NW China. Precambrian Research, 2010, 183(4): 805-816.

[44] Song S G, zhang L F, Niu Y L. Ultra-Deep Origin of Garnet Peridotite from the North Qaidam Ultrahigh-Pressure Belt, Northern Tibetan Plateau, NW China. American Mineralogist, 2004, 89(8/9): 1330-1336.

[45] Song S G, Zhang L F, Niu Y L, . 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. Earth and Planetary Science Letters, 2005, 234(1/2): 99-118.

[46] Walsh E O, Hacker B R. The Fate of Subducted Continental Margins: Two-Stage Exhumation of the High-Pressure to Ultrahigh-Pressure Western Gneiss Region, Norway. Journal of Metamorphic Geology, 2004, 22(7): 671-687.

[47] Wei C J, Guan X, Dong J. HT-UHT Metamorphism of Metabasites and the Petrogenesis of TTGs. Acta Petrologica Sinica, 2017, 33(5): 1381-1404. (in Chinese with English Abstract)

[48] White R W, Powell R. Melt Loss and the Preservation of Granulite Facies Mineral Assemblages. Journal of Metamorphic Geology, 2002, 20(7): 621-632.

[49] White R W, Powell R, Holland T J B, . New Mineral Activity-Composition Relations for Thermodynamic Calculations in Metapelitic Systems. Journal of Metamorphic Geology, 2014, 32(3): 261-286.

[50] White R W, Powell R, Holland T J B, . The Effect of TiO2 and Fe2O3 on Metapelitic Assemblages at Greenschist and Amphibolite Facies Conditions: Mineral Equilibria Calculations in the System K2O-FeOMgO- Al2O3-SiO2-H2O-TiO2-Fe2O3. Journal of Metamorphic Geology, 2000, 18(5): 497-511.

[51] Acta Petrrologica et Mineralogica, 1994, 13 2 (in Chinese with English Abstract)

[52] Yang J S, Xu Z Q, Zhang J X, . Early Palaeozoic North Qaidam UHP Metamorphic Belt on the North-Eastern Tibetan Plateau and a Paired Subduction Model. Terra Nova, 2002, 14(5): 397-404.

[53] Yang J S, Xu Z Q, Li H B, . The Eclogites have been Found in the Northern Qaidam Basin, Western China. Chinese Science Bulletin, 1998, 43(14): 1544-1549.

[54] Yang J S, Xu Z Q, Song S G, . Discovery of Coesite in the North Qaidam Early Palaeozoic Ultrahigh Pressure (UHP) Metamorphic Belt, NW China. Acta Geologica Sinica, 2001, 75(2): 175-179. (in Chinese with English Abstract)

[55] Yang J Z, Liu X C, Wu Y B, . Zircon Record of Ocean-Continent Subduction Transition Process of Dulan UHPM Belt, North Qaidam. Journal of Earth Science, 2015, 26(5): 617-625.

[56] Yin C Q, Zhao G C, Wei C J, . Metamorphism and Partial Melting of High-Pressure Pelitic Granulites from the Qianlishan Complex: Constraints on the Tectonic Evolution of the Khondalite Belt in the North China Craton. Precambrian Research, 2014, 242: 172-186.

[57] Yu S Y, Zhang J X, Li H K, . Geochemistry, Zircon U-Pb Geochronology and Lu-Hf Isotopic Composition of Eclogites and Their Host Gneisses in the Dulan Area, North Qaidam UHP Terrane: New Evidence for Deep Continental Subduction. Gondwana Research, 2013, 23(3): 901-919.

[58] Zhang C, Holtz F, Koepke J, . Constraints from Experimental Melting of Amphibolite on the Depth of Formation of Garnet-Rich Restites, and Implications for Models of Early Archean Crustal Growth. Precambrian Research, 2013, 231: 206-217.

[59] Zhang C, van Roermund H, Zhang L F, . 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. Lithos, 2012, 136–139: 27-45.

[60] Zhang G B, Ellis D J, Christy A G, . UHP Metamorphic Evolution of Coesite-Bearing Eclogite from the Yuka Terrane, North Qaidam UHPM Belt, NW China. European Journal of Mineralogy, 2009, 21(6): 1287-1300.

[61] Zhang J X, Meng F C, Yang J S. Eclogitic Metapelites in the Western Segment of the North Qaidam Mountains: Evidence on “in situ” Relationship between Eclogite and Its Country Rock. Science in China Series D: Earth Sciences, 2004, 47(12): 1102-1112.

[62] Zhang J X, Yang J S, Mattinson C G, . Two Contrasting Eclogite Cooling Histories, North Qaidam HP/UHP Terrane, Western China: Petrological and Isotopic Constraints. Lithos, 2005, 84(1/2): 51-76.

[63] Earth Science Frontiers, 2007, 14 1 (in Chinese with English Abstract)

[64] Zhang J X, Mattinson C G, Meng F, . Polyphase Tectonothermal History Recorded in Granulitized Gneisses from the North Qaidam HP/UHP Metamorphic Terrane, Western China: Evidence from Zircon U-Pb Geochronology. Geological Society of America Bulletin, 2008, 120(5/6): 732-749.

[65] Zhang J X, Mattinson C G, Yu S Y, . 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. Journal of Metamorphic Geology, 2010, 28(9): 955-978.

[66] Zhang J X, Yu S Y, Mattinson C G. Early Paleozoic Polyphase Metamorphism in Northern Tibet, China. Gondwana Research, 2017, 41: 267-289.

[67] Zhang Y H, Wei C J, Lu M J, . P-T-t Evolution of the High-Pressure Mafic Granulites from Northern Hengshan, North China Craton: Insights from Phase Equilibria and Geochronology. Precambrian Research, 2018, 312: 1-15.

[68] Zhao G C, Cawood P A, Wilde S A, . High-Pressure Granulites (Retrograded Eclogites) from the Hengshan Complex, North China Craton: Petrology and Tectonic Implications. Journal of Petrology, 2001, 42(6): 1141-1170.