| 内蒙古索伦山地区三叠纪侵入岩锆石U-Pb年龄、岩石地球化学特征及地质意义 |
| |
| 引用本文： | 连琛芹,李钢柱,于洋,姚佛军,张思源,王丕军,崔舜铫.内蒙古索伦山地区三叠纪侵入岩锆石U-Pb年龄、岩石地球化学特征及地质意义[J].地球科学,2021,46(1):87-100. |
| |
| 作者姓名： | 连琛芹 李钢柱 于洋 姚佛军 张思源 王丕军 崔舜铫 |
| |
| 作者单位： | 1.中国地质大学地球科学与资源学院, 北京 100083 |
| |
| 基金项目： | 中央级公益性科研院所基本科研业务费专项资金资助项目;中国地质调查局地质调查项目;中国地质调查局基本科研业务费项目 |
| |
| 摘 要： | 内蒙古索伦山地区朱恩道欧恩呼尔新识别出一套早中生代侵入岩，主要由角闪二长岩和二长闪长岩组成.通过LA-ICP-MS锆石U-Pb定年确定，角闪二长岩的结晶年龄为248±1 Ma(MSWD=1.1)，表明该岩体形成于早三叠世.它们的SiO2含量介于51.82%~60.17%之间，具有高镁(Mg#=53.17~59.03)、富碱(K2O+Na2O=7.36%~9.83%)、富钠(K2O/Na2O=0.25~0.53)特征，属于准铝质碱性岩.样品稀土总量变化范围为117.52×10-6~160.89×10-6，表现出一致的稀土元素和微量元素配分型式，即呈现出轻稀土元素相对于重稀土元素富集((La/Yb)N=9.57~15.42)的右倾曲线，且无明显Eu异常(δEu=0.76~1.00)，并富集Ba、Sr等大离子亲石元素，亏损Nb、Ta、Ti、Y等高场强元素，高Sr、低Y、高Sr/Y比值，具有高镁埃达克质闪长岩的地球化学特征.综合岩石地球化学特征及区域构造背景，朱恩道欧恩呼尔早中生代高镁埃达克质闪长岩类是由残余俯冲洋壳部分熔融形成的熔体与地幔橄榄岩相互作用而形成.朱恩道欧恩呼尔富碱侵入岩的形成与华北板块与西伯利亚板块碰撞后的伸展作用有关，这些新的年龄和岩石地球化学数据表明古亚洲洋闭合早于248 Ma.
|
| 关 键 词： | 后碰撞 早三叠世 LA-ICP-MS U-Pb年龄 索伦山 地球化学 |
| 收稿时间： | 2019-01-28 |
LA-ICP-MS Zircon U-Pb Age and Whole-Rock Geochemistry of the Triassic Intrusive Rocks in the Solon Obo Area,Inner Mongolia and Its Geological Significance |
| |
| Lian Chenqin,Li Gangzhu,Yu Yang,Yao Fojun,Zhang Siyuan,Wang Pijun,Cui Shunyao.LA-ICP-MS Zircon U-Pb Age and Whole-Rock Geochemistry of the Triassic Intrusive Rocks in the Solon Obo Area,Inner Mongolia and Its Geological Significance[J].Earth Science-Journal of China University of Geosciences,2021,46(1):87-100. |
| |
| Authors: | Lian Chenqin Li Gangzhu Yu Yang Yao Fojun Zhang Siyuan Wang Pijun Cui Shunyao |
| |
| Institution: | (School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Hohhot Natural Resources Comprehensive Survey Center,China Geological Survey,Huhhot 010010,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Institution of Geological Survey,China University of Geosciences,Wuhan 430074,China) |
| |
| Abstract: | The Early Mesozoic Zhuendaoouenhuer intrusion is located in Solon Obo area,Inner Mongolia. It mainly consists of hornblende monzonite and monzodiorite.LA-ICP-MS zircon U-Pb dating yields the Early-Triassic age of 248±1 Ma for the hornblende monzonite. Both the hornblende monzonite and monzodiorite are rich in silica (SiO2=51.82%-60.17%),MgO(Mg#=53.17-59.03),alkali (K2O+Na2O=7.36%-9.83%) and Na(K2O/Na2O=0.25-0.53),suggesting a typical alkaline series with the metaluminous feature (A/CNK=0.53-0.75).The rocks are poor in rare earth elements(ΣREE=117.52×10-6-160.89×10-6),enriched in LREE(La/Yb)N=9.57-15.42] and LILEs (Ba、Sr),and depleted in HFSE,especially Nb,Ta,Ti,Y,and insignificant Eu anomalies(δEu=0.76-1.00),and had high Sr,low Y,high Sr/Y ratio,suggesting geochemical characteristics of high-Mg adakite diorite. The combination of geological setting and geochemical characteristics of the Zhuendaoouenhuer high-Mg adakitic rocks were most probably derived from partial melting of the remnant Paleo-Asian oceanicsubducted slabs and subsequently hybridized by mantle peridotite. The formation of the Zhuendaoouenhueradakitic intrusive rocks is related to the extension of the collision between the North China plate and the Siberian plate. These new age and rock geochemical data indicate that the ancient Asian Ocean closed earlier than 248 Ma. |
| |
| Keywords: | post collision Early Ttriassic epoch LA?ICP?MS U?Pb dating Solon Obo geochemistry |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
| 点击此处可从《地球科学》下载免费的PDF全文 |
|
