Abstract
A combined study of CL imaging, LA-ICP-MS U-Pb dating and trace element analysis were carried out for zircon grains from high-pressure basic granulite at Songshugou in North Qinling. The zircons display core-rim internal texture. The cores are made up of sector or planar domains, partially displaying weak zoning or misty texture, and have the feature of low content of Th, U, REE, HREE, low Th/U ratio and high (Nd/Yb)n ratio, and the REE pattern typical for zircon coexisting with garnet. These features indicate the metamorphic genesis for the zircon cores. The rims have narrow light margins (<30ìm in width) around the cores and boundaries between core and rim are rounded or lough-like, indicating that the rims were formed during retrograde metamorphism. U-Pb isotopic data of 24 spots from the cores of 11 zircon grains yield a 206Pb/238U weighted average age of 485±3.3 Ma, which is interpreted as the peak metamorphic age of high-pressure (HP) basic granulite. This age is well consistent within error with that of ultrahigh-pressure (UHP) eclogite and its country rock gneiss (507±37 Ma) that occur at the north side of the Qinling Group, possibly indicating the occurrence of two contemporaneous Early-Paleozoic HP to UHP metamorphic rock belts on the north and south sides of the Qinling Group. Combining with the regional geological studies and the distribution of Early-Paleozoic granites related to subduction and collision, the two HP to UHP metamorphic belts may be the products of continental crust bi-directional deep subduction toward Qinling micro-block caused by the subduction and collision of Paleozoic Qinling ocean and Erlang** ocean, respectively.
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Hu, N. G., Zhao, D. L., Xu, B. Q. et al., Discovery of coesitebearing eclogite from the northern Qinling and its significances, Chinese Science Bulletin, 1995, 40(2): 174–176.
Hu, N. G., Zhao, D. L., Xu, B. Q., Petrography and metamorphism study on high-ultrahigh pressure eclogite from Guanpo area, northern Qinling Mountain, J. Mineral Petrology (in Chinese), 1995, 15(4): 2–9.
Yang, J. S., Xu, Z. Q., Pei, X. Z. et al., Discovery of diamond in north Qinling: evidence for a giant UHPM belt across central China and recognition of Paleozoic and Mesozoic dual deep subduction between north China and Yangtze plates, Acta Geologica Sinica (in Chinese), 2002, 76(4): 484–495.
Liu, L., Zhou, D. W., Discovery and study of high pressure mafic granulites in Songshugou area of Shangnan, East Qinling, Chinese Science Bulletin, 1995, 40(4): 400–404.
Liu, L., Zhou, D. W., Dong, Y. P. et al., High pressure metabasites and their retrograde metamorphic P-T-t path from Songshugou area, eastern Qinling Mountain, Acta Petrologica Sinica (in Chinese with English abstract), 1995, 11(2): 127–136.
Liu, L., Zhou, D. W., Wang, Y. et al., Study and implication of the high-pressure felsic granulite in the Qinling complex of East Qinling, Science in China, Series D, 1996, 39(Suppl.): 60–68.
Chen, D. L., Liu, L., Wang, Y. et al., Discovery and its significance of high-pressure impure marbles in Qinling complex from eastern Qinling Mountain, J. Northwest University (in Chinese), 2001, 31(4): 324–328.
Liu, L., Chen, D. L., Sun, Y. et al., Discovery of relic majoritic garnet in felsic metamorphic rocks of Qinling complex, north Qinling orogenic belt, China, in Alice Wain Memorial Western Norway Eclogite Field Symposium, Selje, western Norway, 2003, 81.
Wang, T., Zhang, G. W., Pei, X. Z. et al., Possibility of the existence of a Neoproterozoic NW trending orogenic belt in the North Qinling and convergence and breakup of blocks on its two sides, Geological Bulletin of China (in Chinese with English abstract), 2002, 21(8-9): 516–522.
Zhang, G. W., Zhang, B. R., Yuan, X. C. et al., Qinling Orogenic Belt and Continental Dynamics (in Chinese), Bei**g: Science Press, 2001, 1–806.
Meng, Q. R., Zhang, G. W., Timing of collision of the North and South China blocks: Controversy and reconciliation, Geology, 1999, 27: 1–96.
Liu, L., Zhou, D. W., Wang, Y. et al., Protolith properties of garnet-bearing high-pressure metamorphic rocks from Songshugou, east Qinling, J. Northwest University (Natural Science Edition), 1996, 26(1): 105–110.
Liu, X. M., Gao, S., Yuan, H. L. et al., Analysis of 42 major and trace elements in glass standard reference material by 193 nm La-ICPMS, Acta Petrologica Sinica, 2002, 18(3): 408–418.
Andersen, T., Correction of common lead in U-Pb analyses that do not report 204Pb, Chem. Geol. (in Chinese with English abstract), 2002, 192: 59–79.
Yuan, H. L., Wu, F. Y., Gao, S. et al., Determination of U-Pb age and rare earth element concentrations of zircons from Cenozoic intrusions in northeastern China by laser ablation ICP-MS, Chinese Science Bulletin, 2003, 48(22): 2411–2421.
Li, X., Liang, X. R., Sun, M. et al., Geochronology and geochemistry of single-grain zircons: Simultaneous in-situ analysis of U-Pb age and trace elements by LAM-ICP-MS, Eur. J. Mineral, 2000, 12: 1015–1024.
Vavra, G., Gebauer, D., Schmid, R. et al., Multiple zircon growth and recrystallization during polyphase Late Carboniferous to Triassic metamorphism in granulites of the Ivrea Zone (Southern Alps): an ion microprobe (SHRIMP) study, Contrib. Mineral Petrol., 1996, 122: 337–358.
Vavra, G., Schmid, R., Gebauer, D., Internal morphology, habit and U-Th-Pb microanalysis of amphibolite-to-granulite facies zircons: geochronology of the Ivrea Zone (Southern Alps), Contrib. Mineral Petrol., 1999, 134: 380–404.
Rubatto, D., Gebauer, D., Compagnoni, R., Dating of eclogite-facies zircons: the age of Alpine metamorphism in the Sesia-Lanzo Zone (Western Alps), Earth and Planetary Science Letters, 1999, 167: 141–158.
Heaman, L. M., Bowins, R., Crocket, J., The chemical composition of igneous zircon suites: implications for geochemical tracer studies, Geochim. Cosmochim. Acta, 1990, 54: 1597–1607.
Rubatto, D., Williams, I. S., Imaging, trace element geochemistry and mineral inclusions: linking U-Pb ages with metamorphic conditions, EOS Trans., 2000, 21: 2520.
Whitehouse, M. J., Platt, J. P., Dating high-grade metamorphism-constraints from rare-earth elements in zircon and garnet, Contrib. Mineral Petrol., 2003, 145: 61–74.
Rubatto, D., Zircon trace element geochemistry: partitioning with garnet and the link between U-Pb ages and metamorphism, Chem. Geol., 2002, 184: 123–138.
Liu, F. L., Xu, Z. Q., Song, B., Determination of UHP and retrogradle metamorphic ages of the Sulu terrane: Evidence from SHRIMP U-Pb dating on zircons of gneissic rocks, Acta Geologica Sinica (in Chinese with English abstract), 2003, 77(2): 229–237.
Yang, J. S., Liu, F. L., Wu, C. L., Two ultrahigh pressure metamorphic events recognized in the central orogenic belt of China: evidence from the U-Pb dating of coesite-bearing zircons, Acta Geologica Sinica (in Chinese with English abstract), 2003, 77(4): 463–477.
Liu, L., Chen, D. L., Zhang, A. D. et al., The peak metamorphic age and its geological significance of high-pressure to ultrahigh pressure rocks in northern Qinling Mountains, Abstract for structural geological development strategic symposium at the begin of 21 century at **’an (in Chinese), October 2003, 93–96.
Zhang, A. D., Liu, L., Wang, Y., Geochemistry and tectonic setting of the protolith of eclogite in north Qinling, J. Northwest University (Natural Science edition) (in Chinese with English abstract), 2003, 33(2): 191–195.
Sun, W. D., Li, S. G., Sun, Y. et al., Chronology and geochemistry of a lava pillow in the Erlang** group at **%20group%20at%20**xia%20in%20the%20north%20Qinling%20Mountains&journal=Geological%20Review&volume=42&issue=2&pages=144-153&publication_year=1996&author=Sun%2CW.%20D.&author=Li%2CS.%20G.&author=Sun%2CY."> Google Scholar
Sun, W. D., Li, S. G., **ao, Y. L. et al., The discovery of isoland arc andesite from Danfeng Group Heihe, north Qinling area and its tectonic significance, Geotectonic et Metallogenia (in Chinese with English abstract), 1995, 19(3): 227–236.
Zhang, Q., Zhang, Z. Q., Sun, Y. et al., Trace element and isotopic geochemistry of metabasalts from Danfeng Group (DFG) in Shangxian-Danfeng area, Shaanxi Province, Acta Petrologica Sinica (in Chinese with English abstract), 1995, 11(1): 43–54.
Cui, Z. L., Sun, Y., Wang, X. R., A discovery of Radiolaria from Danfeng ophiolite, North Qinling and its tectonic significance, Chinese Science Bulletin, 1996, 41(11): 916–919.
Wang, X. R., Hua, H., Sun, Y., Study on microfossil from Erlang** Group in Wantan area, **%20Group%20in%20Wantan%20area%2C%20**xia%20County%2C%20Henan%20Province&journal=J.%20Northwest%20University&volume=25&issue=4&pages=353-358&publication_year=1995&author=Wang%2CX.%20R.&author=Hua%2CH.&author=Sun%2CY."> Google Scholar
Xue, F., Kroner, A., Reischmann, T. et al., Palaeozoic pre-and post-collision calc-alkaline magmatism in the Qinling orogenic belt, central China, as documented by zircon ages on granitoid rocks, J. Geol. Society, London, 1996, 153: 409–417.
Sun, Y., Yu, Z. P., A discussion on an ancient ocean and Caledonian orogeny in the east Qinling, Collection in a Selection of Papers Presented at the Conference on the Qinling Orogenic Belt (eds. Ye, L. J., Qian, X. L., Zhang, G. W. et al.) (in Chinese), **’an: Northwest University Publishing House, 1991, 167–173.
Li, S. G., Chen, Y. Z., Zhang, Z. Q. et al., Trace elements and Sr, Nd isotopic geochemistry of the Lajimiao norite-gabbro from the north Qinling belt, Acta Geologica Sinica (in Chinese with English abstract), 1993, 67(4): 310–322.
Lerch, M. F., Xue, F., Kroner, A. et al., A middle Silurian-Early Devonian magmatic arc in the Qinling Mountains of central China, J. Geol., 1995, 103: 437–449.
Lu, S. N., Li, H. K., Chen, Z. H., Characteristics sequence and ages of Neoproterozoic thermo-tectonic events between Tarim and Yangzi blocks—a hypothesis of Yangtze-Tarim connection, Earth Science Frontiers (China University of Geosciences, Bei**g) (in Chinese with English abstract), 2003, 10(4): 321–326.
Li, S. G., Chemical geodynamics of continental subduction, Earth Science Frontiers (China University of Geosciences, Bei**g) (in Chinese with English abstract), 1998, 5(4): 211–234.
Zhang, H. F., Luo, T. C., Zhang, B. R., The source and tectonic setting of the Piaochi batholith in the north Qinling, Geological Review (in Chinese with English abstract), 1996, 42(3): 209–214.
Chen, N. S., Han, Y. J., You, Z. D. et al., Whole-rock Sm-Nd, Rb-Sr and single grain zircon Pb-Pb dating of complex rocks from the interior of the Qinling orogenic belt, western Henan and its crustal evolution, Geochimica (in Chinese with English abstract), 1991, (3): 219–228.
Zhang, G. W., Meng, Q. R., Yu, Z. P. et al., Orogenesis and dynamics of the Qinling Orogen, Science in China, Series D, 1996, 39(3): 225–234.
Huang, X., Sun, B. S., Pan, J. et al., The ages of igneous rocks from eastern Qinling of north China platform and the crustal growth and reworking of the terrane, Acta Petrologica Sinica (in Chinese with English abstract), 1995, 11(2): 312–319.
Zhang, B. R., Zhang, H. F., Zhao, Z. D. et al., Geochemical subdivision and evolution of the lithosphere in East Qinling and adjacent regions: implications for tectonics, Science in China, Series D, 1996, 39(3): 245–255.
Ouyang, J. P., Zhang, B. R., Geochemical evidence for the formation and evolution of North Qinling microcontinent, Science in China, Series D, 1996, 39(Suppl.): 43–49.
Zhu, B. Q., The map** of geochemical provinces in China based on Pb isotopes, J. Geochemical Exploration (in Chinese with English abstract), 1995, 55: 171–181.
Zhu, B. Q., Chang, X. Y., Qiu, H. N. et al., Characteristics of Proterozoic basement on the geochemical steep zones in the continent of China and their implications for setting of superlarge deposits, Science in China, Series D, 1998, 41(Suppl.): 54–64.
Dong, Y. P., Zhang, G. W., Zhu, B. Q., Proterozoic tectonics and evolutionary history of the north Qinling terrane, Acta Geoscientia Sinica (in Chinese with English abstract), 2003, 24(1): 3–10.
Mattauer, M., Matte, P., Malavieille, J. et al., Tectonics of the Qinling belt: build up and evolution of eastern Asia, Nature, 1985, 317: 496–500.
Xu, Z. Q., Lu, Y. L., Tang, Y. Q. et al., Formation of the composite eastern Qinling Chains (in Chinese), Bei**g: Chinese Environmental Science Press, 1988, 1–193.
Zhang, G. W., Mei, Z. C., Zhou, D. W. et al., Formation and evolution of the Qinling tectonic belt, Collection in Formation and Evolution of the Qinling Tectonic Belt (ed. Zhang, G. W.), **’an: Northwest University Publishing House, 1988a, 1–19.
Zhang, G. W., Yu, Z. P., Sun, Y. et al., Basic characteristics and evolution of the Shangdan boundary fault terrain, Collection in Formation and Evolution of the Qinling Tectonic Belt (ed. Zhang, G. W.), **’an: Northwest University Publishing House, 1988b, 29–47.
Zhang, G. W., Kroner, A., Zhou, D. W. et al., Characteristics of the lithospheric composition, structure and evolution of the Qinling orogenic belt, Collection in a Selection of Papers Presented at the Conference on the Qinling Orogenic Belt (ed. Ye, L. J., Qian, X. L., Zhang, G. W. et al.), **’an: Northwest University Publishing House, 1991, 121–138.
Yang, W. R., Yang, S. N., Modern Theories and Methods on the Structure and Evolution of Orogenic Belt-Examples for Eastern Qinling Mountains (in Chinese), Wuhan: China University of Geosciences Press, 1991, 1–191.
Lu, S. N., Chen, Z. H., Li, H. K. et al., Late Mesoproterozoic-early Neoproterozoic evolution of the Qinling orogen, Geological Bulletin of China (in Chinese), 2004, 23(2): 107–112.
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Danling, C., Liang, L., Yong, S. et al. LA-ICP-MS zircon U-Pb dating for high-pressure basic granulite from North Qinling and its geological significance. Chin.Sci.Bull. 49, 2296–2304 (2004). https://doi.org/10.1360/03wd0544
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DOI: https://doi.org/10.1360/03wd0544