Zircon record of ocean-continent subduction transition process of dulan UHPM Belt, North Qaidam

Abstract

The North Qaidam UHPM (ultra-high pressure metamorphism) belt is a typical continental subduction-collision belt containing continental crust deep subduction metamorphic products and oceanic crust relics, And it is an ideal region to study the ocean-continent transition and exhumation mechanism of oceanic UHP rocks during continental deep subduction process. In this paper, we report integrated in situ U-Pb, Lu-Hf and O isotope analyses of zircons from a serpentinized harzburgite as well as U-Pb dating for zircons from a kyanite eclogite from the North Qaidam Dulan UHPM terrane, and use these data to discuss the ocean-continent transition and exhumation mechanisms of oceanic UHP rocks during continental deep subduction. The serpentinized harzburgite was dated at 448±9 Ma, consistent with 455±5 Ma age for the kyanite eclogite within analytical errors. Zircons from the serpentinized harzburgite have uniform ¹⁷⁶Hf/¹⁷⁷Hf values ranging from 0.282 842 to 0.282 883 and ε _Hf(t) values from 11.6 to 13.3. Zircon δ¹⁸O values of the serpentinized harzburgite vary from 4.47‰ to 5.29‰, slightly lower than the value of 5.3‰±0.6‰ for the normal mantle zircon. These Hf-O isotopic features indicate that the protolith of the serpentinized harzburgite was derived from depleted-mantle source, and might have experienced high-temperature rock-water interaction. Therefore, the serpentinized harzburgite was possibly located in the lower part of an oceanic section. The serpentinized harzburgite and kyanite eclogite were both formed due to the subduction of oceanic crust. The UHP metamorphism occurred successively from the oceanic crust to continental crust rocks of the North Qaidam UHP terrane. Low-density serpentinized peridotite and continental rocks possibly have negative buoyancy and play a key effect on preservation and exhumation of high-density oceanic eclogite.

Keywords

continental deep subduction / ocean-continent transformation / North Qaidam / harzburgite / eclogite

References

[1] Blichert-Toft J., Albarede F. The Lu-Hf Geochemistry of Chondrites and the Evolution of the Mantle-Crust System. Earth Planet Sci Lett, 1997, 148: 243-258.

[2] Chen D. L., Sun Y., Liu L., . Zicon U-Pb Dating of Paragneiss Interbed in the UHP Eclogite from Yematan Area, the North Qaidam UHP Terrane, NW China. Acta Petrologica Sinica, 2008, 24(5): 1059-1067.

[3] Cherniak D. J., Watson E. B. Diffusion in Zircon. Reviews in Mineralogy and Geochemistry, 2003, 53(1): 113-143.

[4] Chopin C. Coesite and Pure Pyrope in High-Grade Blueschists of the Western Alps: A First Record and Some Consequences. Contributions to Mineralogy and Petrology, 1984, 86(2): 107-118.

[5] Cloos M. Thermal Evolution of Convergent Plate Margins: Thermal Modeling and Reevaluation of Isotopic AR—Ages for Blueschists in the Franciscan Complex of California. Tectonics, 1985, 4(5): 421-433.

[6] Corfu F. J., Hanchar M., Hoskin P. W., . Atlas of Zircon Textures. Reviews in Mineralogy and Geochemistry, 2003, 53(1): 469-500.

[7] Davies J. H., von Blanckenburg F. Slab Breakoff: A Model of Lithosphere Detachment and Its Test in the Magmatism and Deformation of Collisional Orogens. Earth and Planetary Science Letters, 1995, 129(1): 85-102.

[8] Guillot S., Hattori K. H., Julia S., . Mantle Wedge Serpentinization and Exhumation of Eclogites: Insights from Eastern Ladakh, Northwest Himalaya. Geology, 2000, 28(3): 199-202.

[9] Hall P. S., Kincaid C. Diapiric Flow at Subduction Zones: A Recipe for Rapid Transport. Science, 2001, 292(5526): 2472-2475.

[10] Hermann J., Müntener O., Scambelluri M., . The Importance of Serpentinite Mylonites for Subduction and Exhumation of Oceanic Crust. Tectonophysics, 2000, 327(3): 225-238.

[11] Katayama I., Maruyama S., Parkinson C. D., . Ion Micro-Probe U-Pb Zircon Geochronology of Peak and Retrograde Stages of Ultrahigh-Pressure Metamorphic Rocks from the Kokchetav Massif, Northern Kazakhstan. Earth and Planetary Science Letters, 2001, 188(1): 185-198.

[12] Li X. H., Liu Y., Li Q. L., . Precise Determination of Phanerozoic Zircon Pb/Pb Age by Multicollector SIMS without External Standardization. Geochemistry, Geophysics, Geosystems, 2009, 10(4): 1-21.

[13] Li X. H., Li W., Li Q. L., . Petrogenesis and Tectonic Significance of the ~850 Ma Gangbian Alkaline Complex in South China: Evidence from in Situ Zircon U-Pb Dating, Hf-O Isotopes and Whole-Rock Geochemistry. Lithos, 2010, 114(1): 1-15.

[14] Liu F. L., Liou J. G. Zircon as the Best Mineral for P-T-Time History of UHP Metamorphism: A Review on Mineral Inclusions and U-Pb SHRIMP Ages of Zircons from the Dabie-Sulu UHP Rocks. Journal of Asian Earth Sciences, 2011, 40(1): 1-39.

[15] Liu X. C., Wu Y. B., Gao S., . Record of Multiple Stage Channelized Fluid and Melt Activities in Deeply Subducted Slab from Zircon U-Pb Age and Hf-O Isotope Compositions. Geochimica et Cosmochimica Acta, 2014, 144: 1-24.

[16] Liu X. C., Wu Y. B., Gao S., . First Record and Timing of UHP Metamorphism from Zircon in the Xitieshan Terrane: Implications for the Evolution of the Entire North Qaidam Metamorphic Belt. American Mineralogist, 2012, 97(7): 1083-1093.

[17] Ludwig, K. R., 2003. Isoplot/Ex Version 3.00: A Geological Toolkit for Microsoft Excel, 70.

[18] Mattinson C. G., Wooden J. L., Liou J. G., . Age and Duration of Eclogite-Facies Metamorphism, North Qaidam HP/UHP Terrane, Western China. American Journal of Science, 2006, 306(9): 683-711.

[19] Platt J. P. Dynamics of Orogenic Wedges and the Uplift of High-Pressure Metamorphic Rocks. Geological Society of America Bulletin, 1986, 97(9): 1037-1053.

[20] Rubatto D., Gebauer D., Fanning M. Jurassic Formation and Eocene Subduction of the Zermatt–Saas-Fee Ophiolites: Implications for the Geodynamic Evolution of the Central and Western Alps. Contributions to Mineralogy and Petrology, 1998, 132(3): 269-287.

[21] Rubatto D., Hermann J. Zircon Behaviour in Deeply Subducted Rocks. Elements, 2007, 3(1): 31-35.

[22] Scherer E., Munker C., Mezger K. Calibration of the Lutetium-Hafnium Clock. Science, 2001, 293: 683-687.

[23] Schwartz S., Allemand P., Guillot S. Numerical Model of the Effect of Serpentinites on the Exhumation of Eclogitic Rocks: Insights from the Monviso Ophiolitic Massif (Western Alps). Tectonophysics, 2001, 342(1): 193-206.

[24] 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.

[25] Song S. G., Yang J., Liou J. G., . Petrology, Geochemistry and Isotopic Ages of Eclogites from the Dulan UHPM Terrane, the North Qaidam, NW China. Lithos, 2003, 70(3): 195-211.

[26] Song S. G., Su L., Niu Y. L., . Two Types of Peridotite in North Qaidam UHPM Belt and Their Tectonic Implications for Oceanic and Continental Subduction: A Review. Journal of Asian Earth Sciences, 2009, 35(3): 285-297.

[27] 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.

[28] 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): 99-118.

[29] Stacey J. T., Kramers J. D. Approximation of Terrestrial Lead Isotope Evolution by a Two-Stage Model. Earth and Planetary Science Letters, 1975, 26(2): 207-221.

[30] Valley J. W. Oxygen Isotopes in Zircon. Reviews in Mineralogy and Geochemistry, 2003, 53(1): 343-385.

[31] Wu Y. B., Gao S., Zhang H. F., . Timing of UHP Metamorphism in the Hong’an Area, Western Dabie Mountains, China: Evidence from Zircon U-Pb Age, Trace Element and Hf Isotope Composition. Contributions to Mineralogy and Petrology, 2008, 155(1): 123-133.

[32] Wu Y. B., Hanchar J. M., Gao S., . Age and Nature of Eclogites in the Huwan Shear Zone, and the Multi-Stage Evolution of the Qinling-Dabie-Sulu Orogen, Central China. Earth and Planetary Science Letters, 2009, 277: 345-354.

[33] Wu Y. B., Gao S., Liu X. C., . Two-Stage Exhumation of Ultrahigh-Pressure Metamorphic Rocks from the Western Dabie Orogen, Central China. The Journal of Geology, 2011, 119(1): 15-31.

[34] Wu Y. B., Zheng Y. F. Tectonic Evolution of a Composite Collision Orogen: An Overview on the Qinling-Tongbai-Hong’an-Dabie-Sulu Orogenic Belt in Central China. Gondwana Research, 2013, 23: 1402-1428.

[35] Wu Y. B., Zheng Y. F. Genesis of Zircon and its Constraints on Interpretation of U–Pb Age. Chinese Science Bulletin, 2004, 49: 1554-1569.

[36] Yang J. J., Deng J. F. Garnet Peridotites and Eclogites in the Northern Qaidam Mountains, Tibetan Plateau: A First Record. First Workshop on UHP Metamorphism and Tectonics, 1994 Stanford: ILP Task Group III-6

[37] 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. Comptes Rendus de l’Académie des Sciences-Series IIA—Earth and Planetary Science, 2001, 333(11): 719-724.

[38] 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.

[39] Yuan H. L., Gao S., Zhang H. F., . Simultaneous Determinations of U-Pb Age, Hf Isotopes and Trace Element Compositions of Zircon by Excimer Laser-Ablation Quadrupole and Multiple-Collector ICP-MS. Chemical Geology, 2008, 247(1): 100-118.

[40] Zhang C., Zhang L., Herman V. R., . Petrology and SHRIMP U-Pb Dating of Xitieshan Eclogite, North Qaidam UHP Metamorphic Belt, NW China. Journal of Asian Earth Sciences, 2011, 42(4): 752-767.

[41] 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.

[42] Zhang G. B., Song S. G., Zhang L. F., . The Subducted Oceanic Crust within Continental-Type UHP Metamorphic Belt in the North Qaidam, NW China: Evidence from Petrology, Geochemistry and Geochronology. Lithos, 2008, 104(1): 99-118.

[43] Zhang G. B., Song S. G., Zhang L. F. Ophiolite Type Mantle Peridotite from Shaliuhe, North Qaidam UHPM Belt, NW China and its Tectonic Implications. Acta Petrologica Sinica, 2005, 21(4): 1049-1058.

[44] Zhang G. B., Zhang L. F. Rodingite from Oceanic Lithology of Shaliuhe Terrane in North Qaidam UHPM Belt and Its Geological Implication. Earth Science Frontiers, 2011, 18(2): 151-157.

[45] 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.

[46] 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.