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| 西藏拉萨地块南缘晚白垩世镁铁质岩浆作用的年代学、地球化学及意义 | |
| 引用本文： | 管琪,朱弟成,赵志丹,董国臣,莫宣学,刘勇胜,胡兆初,袁洪林.西藏拉萨地块南缘晚白垩世镁铁质岩浆作用的年代学、地球化学及意义[J].岩石学报,2011,27(7):2083-2094. |
| 作者姓名： | 管琪 朱弟成 赵志丹 董国臣 莫宣学 刘勇胜 胡兆初 袁洪林 |
| 作者单位： | 1. 地质过程与矿产资源国家重点实验室,中国地质大学地球科学与资源学院,北京100083;石家庄经济学院资源学院,石家庄050031 2. 地质过程与矿产资源国家重点实验室,中国地质大学地球科学与资源学院,北京100083 3. 地质过程与矿产资源国家重点实验室,中国地质大学地球科学学院,武汉430074 4. 大陆动力学国家重点实验室,西北大学地质学系,西安710069 |
| 基金项目： | 本文受国家973项目(2011CB403102、2009CB421002)、国家自然科学基金项目(40830317、40973062、40973026)、中央高校基本科研业务费专项资金项目(2010ZD02)、教育部新世纪优秀人才项目(NCET-10-0711)和中国地质调查局工作项目(1212011121260, 1212011121066)联合资助. |
| 摘 要： | 镁铁质岩石所反映出的壳幔作用信息可以为地壳增生发生的时间和方式提供可靠的证据。本文报道了南部拉萨地块东段朗县至米林之间晚白垩世镁铁质岩石的岩石学、锆石U-Pb年代学、全岩地球化学以及锆石Hf同位素数据。锆石U-Pb定年结果表明,角闪辉长岩侵位于98~88Ma,高Al2O3(17.25%~19.46%),低MgO含量(3.89%~5.07%)及Mg#(44~50),与高铝玄武岩特征相似,属于中钾钙碱性岩石,富集大离子亲石元素(LILE)、亏损高场强元素(HFSE),铕异常不明显(δEu=0.82~1.06),(87Sr/86Sr)i值为0.70427,εNd(t)值为3.0,具有高且正的锆石εHf(t)值(+11.8~+17.2)。这些晚白垩世镁铁质岩石可能是来自俯冲板片的沉积物熔体交代地幔楔物质发生部分熔融并经历一定程度镁铁质矿物分离结晶作用产物。 |
| 关 键 词： | 晚白垩世 镁铁质岩石 地幔楔熔融 南部拉萨地块 西藏 |
| 收稿时间： | 4/2/2011 12:00:00 AM |
| 修稿时间： | 2011/5/18 0:00:00 |
Zircon U-Pb chronology, geochemistry of the Late Cretaceous mafic magmatism in the southern Lhasa Terrane and its implications |
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| GUAN Qi,ZHU DiCheng,ZHAO ZhiDan,DONG GuoChen,MO XuanXue,LIU YongSheng,HU ZhaoChu and YUAN HongLin.Zircon U-Pb chronology, geochemistry of the Late Cretaceous mafic magmatism in the southern Lhasa Terrane and its implications[J].Acta Petrologica Sinica,2011,27(7):2083-2094. | |
| Authors: | GUAN Qi ZHU DiCheng ZHAO ZhiDan DONG GuoChen MO XuanXue LIU YongSheng HU ZhaoChu and YUAN HongLin |
| Institution: | State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;College of Resources, Shijiazhuang University of Economics, Shijiazhuang 050031, China;State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China;State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, China |
| Abstract: | Implication for mass exchange between mantle and crust reflected by mafic rocks should provide reliable evidence for when and how the crustal growth happened. To explore this issue, we present zircon LA-ICPMS U-Pb data, geochemical and Hf isotopic data for the mafic rocks from the eastern segment of the southern Lhasa Terrane. These mafic rocks emplaced at 98~88Ma are of high Al2O3 (17.25%~19.46%), low MgO (3.89%~5.07%) and Mg# (44~50), similar to high-alumina basalt. They are enriched in LILE, depleted in ... |
| Keywords: | Late Cretaceous Mafic rocks Mantle wedge melting Southern Lhasa Terrane Tibet |
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