| 华北克拉通的组成及其变质演化 |
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| 关键词:North China Craton M-LP/HP/UHT metamorphism mantle plume underplating p-T paths collision and collage |
| 基金项目:中国地质调查局工作项目(编号: 1212010811048) |
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| Constituents and Evolution of the Metamorphic Basement of the North China Craton |
| Precambrian metamorphic basement of North China Craton (NCC) is composed of five sets of different types of metamorphic rocks. In the formation process, the NCC experienced multiple tectonic activities, multiple magma emplacement, multiple metamorphism, different degrees of migmatization and anatexis. The rocks suffered multiple superposition of different geological processes and, therefore, the NCC has a complicated evolution history. From Archean to Late Paleoproterozoic, the NCC mainly underwent five stages of regional metamorphism. Anshan area experienced amphibolite facies metamorphism in Paleo/Meso-Archean. However, no metamorphic ages have been obtained except 3 560 Ma and 3 000~3 300 Ma metamorphic ages obtained from TTG series. In Lushan Taihua complex of Henan, 2 776~2 792 Ma and 2 671~2 651 Ma metamorphic ages are obtained from Mesoarchean amphibolites, which represent metamorphism in early Neoarchean. Granulites-TTG series and granite-greenstone belt of Neoarchean both experienced metamorphic transformation in late Neoarchean and early Paleoproterozoic. In Paleoproterozoic, on the northern margin of the NCC, L-MP/HP granulite facies metamorphism occurred between 1 965~1 900 Ma and UHT metamorphism appeared locally. This metamorphism is considered to be related to the continental collision and subsequent mantle upwelling. In Late Paleoproterozoic (1 890~1 800 Ma), in the central and eastern NCC, high-pressure granulite facies to amphibolite facies metamorphism occurred in Jiao–Liao–Ji belt, which indicates the collision and collage of continental blocks. Different types of metamorphic rock series experienced different kinds of metamorphism, which reflect different tectonic settings. A large number of late Archean TTG rock series and planar distribution M-LP granulites are mainly located in the central-northern part of NCC. They generally have counterclockwise p-T paths, which reflect mantle plume underplating tectonic setting. Granite-greenstone series of Neoarchean experienced a metamorphism in late Neoarhcean and early Paleoproterozoic with clockwise p-T paths, reflecting a compound tectonic setting of back-arc and mantle plume. Two metamorphic events that occurred in the Late Paleoproterozoic formed high-pressure granulite facies with clockwise p-T paths, reflecting the collision and collage of continental blocks, which means that plate tectonics system similar to Phanerozoic had appeared. |
| SHEN Qi-han,GENG Yuan-sheng,GENG Yuan-sheng.2016.Constituents and Evolution of the Metamorphic Basement of the North China Craton[J].Acta Geoscientica Sinica,37(4):387-406. |
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