| 桐柏造山带古元古代变质基性岩的锆石U-Pb年龄及其地质意义 |
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| 关键词:Paleoproterozoic two metamorphic episodes Yangtze block Tongbai orogen |
| 基金项目:国家973项目(编号: 2009CB825006)；中国地质调查局国土资源大调查项目(编号: 1212010711812) |
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| Zircon U-Pb Ages of Paleoproterozoic Metabasites from the Tongbai Orogen and Their Geological Significance |
| The Tongbai orogen is situated at the junction between the Qinling and Dabie orogenic belts. Its northern part corresponds to the North Qinling medium- to high-grade metamorphic complexes, whereas the southern part belongs to the westward continuation of the Dabie HP/UHP metamorphic complexes. Zircon U-Pb dating reveals a protolith age of (1961?23) Ma and a zircon recrystallization or growth age of (1949?51) Ma for an eclogite, and a metamorphic age of (1936?26) Ma for a garnet amphibolite (retrograded eclogite?). These data suggest that these rocks might have suffered Paleoproterozoic metamorphism prior to Permian-Triassic HP metamorphism. Based on the available geochronological data from the Tongbai-Dabie-Sulu orogen, the authors have inferred the existence of two episodes of Paleoproterozoic tectonothermal events in northern Yangtze block. The first episode occurred at 1.97-1.93 Ga, probably related to the assembly of the Columbia supercontinent. The second episode took place at 1.85-1.82 Ga, resulting either from the protracted assembly of the Columbia supercontinent or from the accretionary orogenesis along the northern margin of the Yangtze block. |
| HU Juan,LIU Xiao-chun,QU Wei,CUI Jian-jun.2012.Zircon U-Pb Ages of Paleoproterozoic Metabasites from the Tongbai Orogen and Their Geological Significance[J].Acta Geoscientica Sinica,33(3):305-315. |
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