Early Proterozoic Granulites in Central Korea: Tectonic Correlation with Chinese Cratons
Early Proterozoic Granulites in Central Korea: Tectonic Correlation with Chinese Cratons
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DOI：
10.1086/317951
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发表时间：
2000-11
期刊：
影响因子：
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通讯作者：
Seung Ryeol Lee;M. Cho;K. Yi;R. Stern
中科院分区：
文献类型：
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作者：
Seung Ryeol Lee;M. Cho;K. Yi;R. Stern
在朝鲜半岛中部（以前被认为是东部临津江带）发现了连贯的麻粒岩杂岩体。该麻粒岩杂岩（华川麻粒岩杂岩[HGC]）经历了两个构造变质事件周期。第一个事件对应于地壳增厚，随后是麻粒岩相变质作用峰值和相关的部分熔融。准等压冷却路径，分别由镁铁质和泥质麻粒岩中次生石榴石地幔斜辉石和次生蓝晶石的出现表明，表明在 HGC 折返之前在中地壳水平存在大量停留时间。峰值变质作用的时间可以追溯到 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} 混合岩粒岩中锆石上的无分区过度生长边缘\usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$1872\pm 7$$ \end{document} (2) Ma，使用离子微探针。然而，锆石碎屑核给出的历时 U-Pb 年龄约为2.30、2.45、2.65 和 2.90 Ga，证明韩国存在太古代原岩。混合岩麻粒岩的 Sm-Nd 模型年龄（约 2.8-2.6 Ga）进一步表明，在麻粒岩相变质作用之前，来自地幔的新生物质显着增加。第二次构造变质事件可能是 HGC 最终向地表折返的原因。根据现有同位素数据，折返年龄被解释为二叠纪-三叠纪。这些结果表明京畿地块与扬子克拉通的相关性，并且作为推论，该地块和临津江带都对应于中国碰撞带的向东延续。
A coherent granulite complex has been discovered in the central part of the Korean Peninsula, formerly regarded as the eastern Imjingang belt. This granulite complex (Hwacheon granulite complex [HGC]) experienced two cycles of tectonometamorphic events. The first event corresponded to crustal thickening, followed by peak granulite‐facies metamorphism and associated partial melting. The quasi‐isobaric cooling path, suggested by the occurrences of secondary garnet mantling orthopyroxene and secondary kyanite in mafic and pelitic granulites, respectively, indicates substantial residence time at midcrustal levels prior to exhumation of the HGC. The timing of peak metamorphism was dated from the unzoned overgrowth rims on zircons in a migmatitic granulite at \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$1872\pm 7$$ \end{document} (2) Ma, using an ion microprobe. Detrital cores of zircon, however, give diachronous U‐Pb ages of ca. 2.30, 2.45, 2.65, and 2.90 Ga, attesting to the presence of Archean protoliths in South Korea. Sm‐Nd model ages of migmatitic granulites (ca. 2.8–2.6 Ga) further suggest that a significant addition of juvenile materials from the mantle took place prior to granulite‐facies metamorphism. The second tectonometamorphic event may be responsible for the final exhumation of the HGC toward the surface. The age of exhumation is interpreted to be Permo‐Triassic on the basis of available isotopic data. These results suggest correlation of the Gyeonggi massif with the Yangtze craton, and as a corollary, that both this massif and the Imjingang belt correspond to the eastward continuation of the Chinese collisional belt.