Discovery of Early Paleozoic eclogite from the East Kunlun, Western China and its tectonic significance
Discovery of Early Paleozoic eclogite from the East Kunlun, Western China and its tectonic significance
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DOI：
10.1016/j.gr.2012.06.007
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发表时间：
2013-03
影响因子：
6.1
通讯作者：
F. Meng;Jianxin Zhang;Meihui Cui
中科院分区：
文献类型：
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作者：
F. Meng;Jianxin Zhang;Meihui Cui
在东昆仑东部、中国西部发现的榴辉岩主要由石榴石+绿辉石+石英+金红石组成。石榴石的端员组成为48-55%的金刚烷、1-2%的橄榄石、19-29%的罗丹石和16-29%的镁铝榴石，绿辉石的翡翠含量为21-63%。榴辉岩的峰变组合记录了>；1.6 Gpa和590°C-650°C的P-T条件。细粒榴辉岩继承的岩浆锆石的锆石U-Pb年龄为934 Ma，代表榴辉岩的原岩年龄。粗粒榴辉岩中的锆石包裹体包括石榴石、绿辉石和金红石，其加权平均年龄为428 Ma，表明榴辉岩的变质年龄。榴辉岩与西侧的晚寒武世(508 Ma)高压麻粒岩共同构成东昆仑早古生代高压变质带。
Eclogites discovered in the eastern part of the East Kunlun Mountains, Western China, are primarily composed of garnet+omphacite+quartz+rutile. The garnets show end-member components of 48–55% almandine, 1–2% spessartine, 19–29% grossularite and 16–29% pyrope, and the omphacite has a jadeite content of 21–63%. The peak-metamorphic assemblage of eclogites records a P–T condition of >1.6GPa and 590°C–650°C. Zircon U–Pb dating of the inherited magmatic zircons from fine-grained eclogite reveals a Neoproterozoic age of 934Ma, representing the protolith age of the eclogite. Zircons from the coarse-grained eclogite contain inclusions of garnet, omphacite and rutile, and yield a weighted mean age of 428Ma, indicating the metamorphic age of eclogite. The eclogites, together with the Late Cambrian (508Ma) high-pressure granulite to the west, constitute an Early Paleozoic high-pressure metamorphic belt in the East Kunlun.