| REE Geochemistry of Precambrian Metamorphic Rocks in Wutaishan Region |
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| 作者姓名： | 吴素珍 |
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| 作者单位： | TianjinInstituteofGeologyandMineralResources,ChineseAcademyofGeologicalSciences |
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| 摘 要： | The metasedimentary-volcanic series of the Wutai and Hutuo groups experienced regional metamorphism and thus turned into moderate-to low-grade metamorphic rocks.REE abundances and REE distribution patterns in the Shizui and Taihuai Subgroup metasedimentary-volcanic rocks are typical of the Archean,whereas the Gaofan Subgroup and the Hutuo Group show post-Archean REE geochemical char-acteristics.Five types of REE distribution pattern are distinguished:(1)rightward inclined smooth curves with little REE anomaly(Eu/Eu*=0.73-0.95) and heavy REE depletion (e.g.the Late Archean metasedimentary rocks);(2)rightward inclined V-shaped curves with sharp Eu anoma-ly (Eu/Eu*=0.48-0.76) and slightly higher ∑REE (e.g.the post-Archean metasedimentary rocks);(3) rightward inclined steep curves with negative Eu anomaly(Eu/Eu*=0.73-0.76) and the lowest ∑REE (e.g.the post-Archean dolomites);(4)rightward inclined,nearly smooth curves with both positive Eu anomaly and unremarkable positive Eu anomaly(Eu/Eu*=0.95-1.25)(e.g.the meta-basic volcanic rocks);and (5) rightward inclined curves with Eu anomaly(Eu/Eu*=1.09-1.19)and heavy REE depletion(e.g.the meta-acid volcanic rocks).Strata of the two groups are considered to have been formed in an island-arc belt-an instable continental petrogenetic environment.
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| 关 键 词： | 稀土元素 地球化学 五台山地区 前寒武纪 变质岩 岛弧带 成岩环境 |
REE geochemistry of precambrian metamorphic rocks in Wutaishan region |
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| Wu SuZhen.REE Geochemistry of Precambrian Metamorphic Rocks in Wutaishan Region[J].Chinese Journal of Geochemistry,1989,8(1):72-83. |
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| Authors: | Wu SuZhen |
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| Institution: | (1) Tianjin Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, China |
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| Abstract: | The metasedimentary-volcanic series of the Wutai and Hutuo groups experienced regional metamorphism and thus turned into moderate-to
low-grade metamorphic rocks. REE abundances and REE distribution patterns in the Shizui and Taihuai Subgroup metasedimentary-volcanic
rocks are typical of the Archean, whereas the Gaofan Subgroup and the Hutuo Group show post-Archean REE geochemical characteristics.
Five types of REE distribution pattern are distinguished: (1) rightward inclined smooth curves with little REE anomaly (Eu
/Eu * = 0.73–0.95) and heavy REE depletion (e. g. the Late Archean metasedimentary rocks); (2) rightward inclined V-shaped
curves with sharp Eu anomaly (Eu /Eu * = 0.48–0.76) and slightly higher ΣREE (e. g. the post-Archean metasedimentary rocks);
(3) rightward inclined steep curves with negative Eu anomaly (Eu /Eu*= 0.73–0.76) and the lowest ΣREE (e.g. the post-Archean
dolomites); (4) rightward inclined, nearly smooth curves with both positive Eu anomaly and unremarkable positive Eu anomaly
(Eu /Eu * = 0.95–1.25) (e. g. the meta —basic volcanic rocks); and (5) rightward inclined curves with Eu anomaly (Eu /Eu *=
1.09–1.19) and heavy REE depletion (e. g. the meta-acid volcanic rocks). Strata of the two groups are considered to have been
formed in an island-arc belt — an instable continental petrogenetic environment. |
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