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Volume 14 Issue 4
Dec 2003
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Article Contents
Zhang Li, Hongfei Zhang, Zengqiu Zhong, Benren Zhang, Linsen Wang. Geochemical Characteristics of Pb Isotope of High-Pressure Metamorphic Rocks and Foliated Granites from HP Unit of Tongbai-Dabie Orogenic Belt. Journal of Earth Science, 2003, 14(4): 321-329.
Citation: Zhang Li, Hongfei Zhang, Zengqiu Zhong, Benren Zhang, Linsen Wang. Geochemical Characteristics of Pb Isotope of High-Pressure Metamorphic Rocks and Foliated Granites from HP Unit of Tongbai-Dabie Orogenic Belt. Journal of Earth Science, 2003, 14(4): 321-329.

Geochemical Characteristics of Pb Isotope of High-Pressure Metamorphic Rocks and Foliated Granites from HP Unit of Tongbai-Dabie Orogenic Belt

Funds:

the National Priority Research and Development Program of China G1999075506

the National Natural Science Foundation of China 40073005

the Research Foundation for Outstanding Young Teachers, China University of Geosciences CUGQNL0327

  • Whole-rock Pb isotopic compositions of the high-pressure (HP) metamorphic rocks, consisting of two-mica albite gneisses and eclogites, and foliated granites from the HP metamorphic unit of the Tongbai-Dabie orogenic belt are firstly reported in this paper. The results show that the HP metamorphic rocks in different parts of this orogenic belt have similar Pb isotopic compositions. The two- mica albite gneisses have 206Pb/204Pb=17.657-18.168, 207Pb/204Pb=15.318-15.573, 208Pb/204Pb=38.315-38.990, and the eclogites have 206Pb/204Pb=17.599-18.310, 207Pb/204Pb=15.465- 15.615, 208Pb/204Pb=37.968-39.143. The HP metamorphic rocks are characterized by upper crustal Pb isotopic composition. Although the Pb isotopic composition of the HP metamorphic rocks partly overlaps that of the ultrahigh-pressure (UHP) metamorphic rocks, as a whole, the former is higher than the latter. The high radiogenic Pb isotopic composition for the HP metamorphic rocks confirms that the subducted Yangtze continental crust in the Tongbai-Dabie orogenic belt has the chemical structure of increasing radiogenic Pb isotopic composition from lower crust to upper crust. The foliated granites, intruded in the HP metamorphic rocks post the HP/UHP metamorphism, have 206Pb/204Pb=17.128-17.434, 207Pb/204Pb=15.313-15.422 and 208Pb/204Pb=37.631-38.122, which are obviously different from the Pb isotopic compositions of the HP metamorphic rocks but similar to those of the UHP metamorphic rocks and the foliated garnet-bearing granites in the UHP unit. This shows that the foliated granites from the HP and UHP units have common magma source. Combined with the foliated granites having the geochemical characteristics of A-type granites, it is suggested that the magma for the foliated granites in the UHP and HP unit would be derived from the partial melting of the retrometamorphosed UHP metamorphic rocks exhumed into middle to lower crust, and partial magmas were intruded into the HP unit.

     

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  • Aitcheson S J, Harmon R S, Moorbath S, et al, 1995. Pb Isotopes Define Basement Domains of the Altiplano, Central Andes. Geology, 23: 555-558
    Cheng Y Q, Liu D Y, Williams I S, et al, 2000. SHRIMP U-Pb Dating of Zircons of a Dark-Coloured Eclogite and a Garnet-Bearing Gneissic-Granitic Rock from Bixiling, Eastern Dabie Area. Acta Geologica Sinica, 74(2): 193-205(in Chinese)
    Cong B L, Wang Q C, 1999. Recent Development in Study of the Dabie-Sulu UHP Rock. Chinese Science Bulletin, 44(12): 1074-1088
    Ernst W G, Liou J G, 1995. Contrasting Plate-Tectonic Styles of Qinling-Dabie-Sulu and Franciscan Metamorphic Belts. Geology, 23: 353-356
    Hacker B R, Wang X, Eide E A, et al, 1996. Qinling-Dabie Ultrahigh-Pressure Metamorphism in Central China. Tectonics, 14: 994-1006
    Hacker B R, Ratschbacher L, Webb L, 1998. U/Pb Zircon Ages Constrain the Architecture of the Ultrahigh-Pressure Qinling-Dabie Orogen, China. Earth and Planetary Science Letters, 161(1-4): 215-236
    Hacker B R, Ratschbacher L, Webb L, et al, 2000. Exhumation of Ultrahigh-Pressure Continental Crust in East Central China: Late Triassic-Early Jurassic Tectonic Unroofing. Journal of Geophysical Research, 105: 13339-13364
    Jahn B M, 1998. Geochemical and Isotopic Characteristics of UHP Eclogites and Ultramafic Rocks of the Dabie Orogen: Implications for Continental Subduction and Collisional Tectonics. In: Hacker B R, Liou J G, eds. When Continents Collide: Geodynamics of Ultrahigh Pressure Rocks. Netherlands: Kluwer Academic Publisher. 203-239
    Li S G, Li HM, Chen Y Z, et al, 1997. The UHP Metamorphic Geochronology of Dabie Mountain-Sulu Terrain-Ⅱ. Zircon U-Pb Isotope System. Science in China(Series D), 27(3): 200-206(in Chinese)
    Li S G, Huang F, Zhou H Y, et al, 2003. U-Pb Isotopic Compositions of the Ultrahigh Pressure Metamorphic(UHPM) Rocks from Shuanghe and Gneisses from Northern Dabie Zone in the Dabie Mountains, Central China: Constraint on the Exhumation Mechanism of UHPM Rocks. Science in China(Series D), 46(3): 200-209
    Liu F L, Zhang Z M, Xu Z Q, 2003. Three-Dimensional Distribution of Ultrahigh-Pressure Minerals in Sulu Terrane. Acta Geologica Sinica, 77(1): 69-84(in Chinese)
    Okay A I, Xu S T, Sengor A M C, 1989. Coesite from the Dabie Shan Eclogite, Central China. Eur J Mineral, 1: 595-598
    Patino Douce A E, McCarty T C, 1998. Melting of Crustal Rocks during Continental Collision and Subduction. In: Hacker B R, Liu J G, eds, When Continents Collide: Geodynamics of Ultrahigh Pressure Rocks. Netherlands: Kluwer Academic Publisher. 27-55
    Suo S T, Zhong Z Q, You Z D, 1999. Location of Triassic Tectonic Suture between Collided Sino-Korean and Yangtze Cratons in Dabie-Sulu Region, China. J China Univ Geosci, 10 (4): 281-286
    Suo S T, Zhong Z Q, You Z D, et al, 2001. Post-Collisional Ductile Extensional Tectonic Framework in the UHP and HP Metamorphic Belts in the Dabie-Sulu Region, China. Acta Geologica Sinica, 75(2): 151-160
    Suo S T, Zhong Z Q, Wei B Z, et al, 2002. Structure and Rheological Evolution of UHP and HP Metamorphic Belts in the Tongbai-Dabie-Sulu Region, China. Earth Science—Journal of China University of Geosciences, 27(5): 549-557
    Taylor S R, Mclennan S M, 1985. The Continental Crust: Its Composition and Evolution. Oxford: Blackwell Scientific Publication. 132
    Wang C, Zeng R, Mooney W D, et al, 2000. A Crustal Model of the Ultrahigh-Pressure Dabie Shan Orogenic Belt, China, Derived from Deep Seismic Refraction Profiling. Journal of Geophysical Research, 105: 10857-10869
    Wang X, Liou J G, Mao H K, 1989. Coesite-Bearing Eclogites from the Dabie Mountains in Central China. Geology, 17: 1085-1088
    Xu Q D, Ouyang J P, Zhang B R, et al, 2002. Tectonic Affinity of Paleozoic Stratigraphic Slices along the Northern Margin in Dabie Orogen, Central China: Evidence from Pb Isotope of Rocks. Progress in Natural Science, 12(6): 438-444
    Xu S T, Okay A I, Ji S Y, et al, 1992. Diamond from the Dabie Shan Metamorphic Rocks and Its Implication for Tectonic Setting. Science, 256: 80-82
    Xu S T, Wu W P, Su W, et al, 1998. Meta-Granitoid from the High-Ultrahigh Pressure Metamorphic Belt in the Dabie 328 Zhang Li, Zhang Hongfei, Zhong Zengqiu, Zhang Benren and Wang LinsenMountains. Acta Petrologica Sinica, 14(1): 42-59(in Chinese)
    Zartman R E, Doe B R, 1981. Plumbotectonics—The Model. Tectonophysics, 75: 135-162
    Zhang H F, Zhang B R, Zhong Z Q, et al, 2000. Geochemistry of Gneisses from Dabie Complex and Tongbai Complex in Qinling-Tongbai-Dabie Orogenic Belt: Implications for Location of Yangtze-Sino-Korean Suture. Journal of China University of Geosciences, 11(4): 392-405
    Zhang H F, Zhong Z Q, Gao S, et al, 2001a. U-Pb Zircon Age of the Foliated Garnet-Bearing Granites in Western Dabie Mountains, Central China. Chinese Science Bulletin, 46 (19): 1657-1660(in Chinese)
    Zhang H F, Gao S, Zhang B R, et al, 2001b. Pb Isotopic Study on Crustal Structure of Dabie Mountains, Central China. Geochimica, 30(4): 395-401(in Chinese)
    Zhang HF, Gao S, Zhong Z Q, et al, 2002. Geochemical and Sr-Nd-Pb Isotopic Compositions of Cretaceous Granitoids: Constraints on Tectonic Framework and Crustal Structure of the Dabieshan Ultrahigh-Pressure Metamorphic Belt, China. Chemical Geology, 281-299
    Zhang H F, Zhang B R, Zhang H Z, et al, 2003. Pb Isotopic Geochemical Study on the Crustal Structure of Tongbaishan. Progress in Natural Science, 13(1): 63-68
    Zhang L, Zhong Z Q, Zhang B R, et al, 2004. Geochemistry and Petrogenesis of Foliated Garnet-Bearing Granites in the High Pressure Metamorphic Unit of the Tongbai-Dabie Orogenic Belt. Geochimica(in Press)(in Chinese)
    Zhang L G, Liu J X, Wang K F, et al, 1995. Block Geology of Eastern Asia Lithosphere—Isotope Geochemistry and Dynamics of Upper Mantle, Basement and Granites. Beijing: Science Press. 252(in Chinese)
    Zhang R Y, Liou J G, Cong B, 1994. Petrogenesis of Garnet-Bearing Ultramafic Rocks and Associated Eclogites in the Su-Lu Ultrahigh-P Metamorphic Terrane, Eastern China. Jour Meta Geol, 12: 169-186
    Zhong Z Q, Suo S T, You Z D, 1999, Regional-Scale Extensional Tectonic Pattern of Ultrahigh-P and High-P Metamorphic Belts from the Dabie Massif, China. International Geological Review, 41: 1033-1041
    Zhong Z Q, Suo S T, You Z D, et al, 2001. Major Constituents of the Dabie Collisional Orogenic Belt and Partial Melting in the Ultrahigh-Pressure Unit. International Geology Review, 43: 226-236
    Zhu B Q, 1994. Geochemical Evidence for the Southern China Block Being a Part of Gondwana. Journal of Southeast Asian Earth Sciences, 9: 319-324
    Zhu B Q, Chang X Y, 2001. Geochemical Provinces and Their Boundaries. Advance in Earth Sciences, 16(2): 153-162
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