| Tectonic Affinity, T-t Path and Uplift Trajectory of Eclogites from Northern Dabie Mountains, Central-Eastern China |
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| 作者姓名： | Liu Yican |
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| 作者单位： | Liu Yican Department of Earth and Space Sciences，USTC，Hefei 230026; Anhui Ins titute of Geology，Hefei 230001 Xu Shutong Anhui Institute of Geology，Hefei 230001 Li Shuguang Department of Earth and Space Sciences，USTC，Hefei 230026 Jiang Laili Chen Guanbao Wu Weiping Anhui Institute of Geology，Hefei 230001 |
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| 基金项目： | ThisstudyissupportedbytheNationalNaturalScienceFoundationofChina (Nos.49794041，4005202，40172079and4007270)andAnhuiBureauofGeologyandMineralResources. |
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| 摘 要： | INTRODUCTIONTheDabieMountainsaretheeasternsectionoftheE WtrendingQinling DabieorogenicbeltbetweentheNorthChinablockandYangtzeblock ,andistransectedatitseasternendbyTan Lufault.Ultrahigh pressuremetamorphic (UHPM)rocksincludingcoesites (Okayetal.,1989;Wangetal.,1989)andmicrodiamonds (Xuetal.,1992b)bearingeclogitesareexposedintheDabieMountainsandSu Luorogen ,whichisthelargestUHPMbeltontheearthsurface .TheUHPMrocksarecomposedofdifferentkindsofmetamorphicrockssuchascoesite anddiamo…
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| 关 键 词： | 榴辉岩 构造亲合力 T-t曲线 大别山 中国 岩石学 地球化学 同位素地质学 |
Tectonic Affinity, T-t Path and Uplift Trajectory of Eclogites from Northern Dabie Mountains, Central-Eastern China |
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| Liu Yican.Tectonic Affinity, T-t Path and Uplift Trajectory of Eclogites from Northern Dabie Mountains, Central-Eastern China[J].Journal of China University of Geosciences,2003,14(1):28-33. |
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| Authors: | LIU Yican XU Shutong Li Shuguang JIANG Laili Chen Guanbao Wu Weiping |
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| Abstract: | Petrologic geochemistry and isotopic chronology of the eclogites suggest that most of the eclogites in northern Dabie Mountains produced from the Triassic Yangtze subducted continental crust (lower crust and formed during the deep subduction) and the metamorphosed mafic-untramafic belt with eclogite, marble and meta-peridotite blocks around the Mozitan-Xiaotian fault zone may represent the meta-tectonic melange produced during the active subduction of an ancient oceanic slab and subsequent collision between the Yangtze and North China continental plates. The cooling history of the eclogites from ～900 ℃ to 300 ℃ can be subdivided into three stages: one isothermal stage and two rapid cooling stages. The initial stage between (230±6) and 210 Ma was a near-isothermal or temperature rise process corresponding to the retrograded metamorphism of granulite-facies with a rapid uplift of 4 nun/a, then two fast cooling stages occurred with cooling rate of ～10 ℃/Ma during 210 Ma to (172±3) Ma and ～4 ℃/Ma during (172±3) Ma to 130 Ma. After the peak metamorphism of eclogite-facies, their initial isothermal stage with slower uplift rate and cooling rate and high-T overprinting of granulite-facies metamorphism is the major difference between the eciogites in northern Dabie Mountains from those in southern Dabie Mountains. This may be one of the most important reasons to preserve few evidences of earlier ultrahigh-pressure metamorphism. |
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| Keywords: | eclogite tectonic affinity T t path and uplift trajectory nor thern Dabie Mountains |
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