| 中条山-吕梁山前寒武纪变质杂岩的独居石电子探针定年研究 |
| |
| 引用本文： | 刘树文,张臣,刘超辉,李秋根,吕勇军,余盛强,田伟,凤永刚.中条山-吕梁山前寒武纪变质杂岩的独居石电子探针定年研究[J].地学前缘,2007,14(1):64-74. |
| |
| 作者姓名： | 刘树文 张臣 刘超辉 李秋根 吕勇军 余盛强 田伟 凤永刚 |
| |
| 作者单位： | 北京大学,造山带与地壳演化教育部重点实验室,地球与空间科学学院,北京,100871 |
| |
| 基金项目： | 国家自然科学基金
,
国家自然科学基金
,
国家自然科学基金 |
| |
| 摘 要： | 中条山和吕梁山前寒武纪变质杂岩是华北克拉通中部带南段的重要组成部分,它们的变质作用及其相关的花岗质岩浆作用是我们全面认识华北克拉通中部带的性质与演化的关键,具有重要的科学意义。中条山前寒武纪变质杂岩两个样品的独居石电子探针Th-U-Pb化学法定年表明,永济和横岭关岩体变质二长花岗质岩石记录了两个主要峰年龄范围,分别为1884.7~1849.9Ma和1743.5~1738.8Ma;前者为变质年龄,后者为流体活化的年龄。吕梁山五个样品的独居石电子探针Th-U-Pb化学法定年表明,石榴石二云母片岩和花岗质片麻岩的记录了>1902Ma、1883.3~1865.6Ma和1731.3Ma。>1902Ma年龄代表早期岩浆和深熔事件,1883.3~1865.6Ma代表峰期变质事件,1731.3Ma代表晚期流体活动事件。石榴石花岗岩记录了1882.8~1850.9Ma深熔岩浆事件。未变质花岗岩脉记录的1742.6Ma和石榴石二云母片岩记录的1731.1Ma为晚期岩浆-流体活动事件。综合上述独居石电子探针定年的结果,不难看出中条山—吕梁山前寒武纪变质杂岩主期变质作用发生在1885~1849Ma,并伴生有同期的S-型花岗质岩浆活动,与恒山—五台山—阜平杂岩的变质变形作用同时发生,进一步证明华北克拉通中部带的拼合作用发生在古元古代晚期。
|
| 关 键 词： | 中条山—吕梁山前寒武纪变质杂岩 电子探针独居石定年 Th-U-Pb 华北克拉通中部带 |
| 文章编号： | 1005-2321（2007）01-0064-11 |
| 收稿时间： | 2006-10-22 |
| 修稿时间： | 2006年10月22 |
EPMA Th-U-Pb dating of monazite for Zhongtiao and Lüliang Precambrian metamorphic complexes |
| |
| Liu Shuwen,Zhang Chen,Liu Chaohui,Li Qiugen,Lü Yongjun,Yu Shengqiang,Tian Wei,Feng Yonggang.EPMA Th-U-Pb dating of monazite for Zhongtiao and Lüliang Precambrian metamorphic complexes[J].Earth Science Frontiers,2007,14(1):64-74. |
| |
| Authors: | Liu Shuwen Zhang Chen Liu Chaohui Li Qiugen Lü Yongjun Yu Shengqiang Tian Wei Feng Yonggang |
| |
| Institution: | The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, China ;School of Earth and Space Sciences, Peking University, Beijing 100871, China |
| |
| Abstract: | Zhongtiao and Lüliang Precambrian metamorphic complexes are essential components of the southern segment of Central Tectonic Zone (CTZ), the North China Craton (NCC). Their metamorphism and related granitic magmatism enable us to correctly understand the nature and evolution of the CTZ in the NCC, with very important scientific significance. EPMA Th-U-Pb dating of monazite for two samples of mozogranitic rocks from Yongji and Henglingguan intrusions in the Zhongtiao Precambrian complex reveal two peak age ranges of 1 884.7-1 849.9 Ma and 1 743.5-1 738.8 Ma. The first is interpreted as mainly metamorphic ages and the last as fluid-activation events. Total five samples from the Lüliang Precambrian metamorphic complex were dated using EPMA Th-U-Pb dating of monazite. Of which the garnet two mica schist and the granitoid gneiss record three age peaks or range of >1 902 Ma, 1 883.3-1 865.6 Ma and 1 731.3 Ma, corresponding to early magmatic and anatectic events, main metamorphism and late fluid-activation, respectively. The two samples of garnet granites yield 1 882.8-1 850.9 Ma, corresponding to anatectic granitic magmatism, which occurred in the simultaneity with the main metamorphism. The unmetamorphosed granite vein yield 1 742.6 Ma, interpreted as forming age of granite vein. Together with the age of 1 731.3 Ma shown by the garnet two mica schist, these young ages may imply important fluid-magmatic activation events. Summary on above these EPMA Th-U-Pb dating results, reveals that the main metamorphism occurred during 1 885-1 849 Ma in the Zhongtiao and the Lüliang Precambrian metamorphic complexes, with the homochronous S-type granitic magmatism. This major metamorphic and cogenetic S-type granitic magmatism are consistent to the metamorphic and deformation events in the Hengshan-Wutai-Fuping complexes, further proving that the amalgamation between the Western and the Eastern blocks in the NCC occurred at late Paleoproterozoic. |
| |
| Keywords: | Zhongtiao and Lueliang Precambrian complexes EPMA dating of monazite Th-U-Pb the CTZ in the NCC |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地学前缘》浏览原始摘要信息 |
| 点击此处可从《地学前缘》下载免费的PDF全文 |
|
