| 西北天山莱历斯高尔岩体年代学、地球化学及其成因 |
| |
| 引用本文： | 解洪晶,武广,朱明田,钟伟,刘军,糜梅.西北天山莱历斯高尔岩体年代学、地球化学及其成因[J].地质科学,2013,48(3):827-846. |
| |
| 作者姓名： | 解洪晶 武广 朱明田 钟伟 刘军 糜梅 |
| |
| 作者单位： | 1. 北京矿产地质研究院 北京 100012;
2. 中国科学院广州地球化学研究所矿物学与成矿学重点实验室 广州 510640;
3. 中国地质科学院矿产资源研究所 北京 100037;
4. 中国科学院地质 与地球物理研究所矿产资源研究重点实验室 北京 100029 |
| |
| 基金项目： | 国家科技支撑计划"十一五"项目，国家"973"项目，国家自然科学基金项目 |
| |
| 摘 要： | 西北天山莱历斯高尔岩体主要由花岗闪长斑岩和二长花岗斑岩组成,二者具有相似的地球化学特征,可能为同源岩浆分异演化的产物。锆石SHRIMP U-Pb年龄显示岩体形成于晚泥盆世(374±4 Ma)。莱历斯高尔岩体具有较高的SiO2(67.75% ～74.71%)含量和K2O/Na2O(1.24～2.20)比值,属于高钾钙碱性系列。稀土元素配分曲线为轻稀土富集型(La/Yb)N(5.25～10.57),具有中等-弱的Eu负异常δEu(0.55～0.92)。微量元素特征显示富集大离子亲石元素(LILE),而亏损高场强元素(HFSE),具有较低的Sr(122×10-6～356×10-6)含量、较高的Y(17.19×10-6～21.82×10-6)和Yb(1.78×10-6～2.57×10-6)含量。岩体的Sr-Nd同位素特征为ISr=0.707 867～0.709 654,εNd(t)=-2.79～-1.46。铅同位素特征为206Pb/204 Pb=18.423～19.915,207 Pb/204Pb=15.576～15.685,208 Pb/204Pb=38.344～39.305。元素和同位素地球化学特征表明,莱历斯高尔岩体岩浆源区主要为中元古代下地壳的部分熔融,并有部分地幔物质的加入。岩体形成于晚泥盆世准噶尔洋向伊犁-中天山微板块陡角度俯冲的大陆弧构造环境。
|
| 关 键 词： | 锆石SHRIMP U-Pb年龄 Sr-Nd-Pb同位素 莱历斯高尔岩体 大陆弧 西北天山 |
| 收稿时间： | 2012-12-15 |
| 修稿时间： | 2012-12-15; |
Geochronology, geochemistry and petrogenesis of the Lailisigaoer intrusion in northwestern Tien Shan, NW China |
| |
| Xie Hongjing
,
Wu Guang
,
Zhu Mingtian
,
Zhong Wei
,
Liu Jun
,
Mi Mei.Geochronology, geochemistry and petrogenesis of the Lailisigaoer intrusion in northwestern Tien Shan, NW China[J].Chinese Journal of Geology,2013,48(3):827-846. |
| |
| Authors: | Xie Hongjing Wu Guang Zhu Mingtian Zhong Wei Liu Jun Mi Mei |
| |
| Institution: | 1. Beijing Institute of Geology for Mineral Resources, Beijing 100012;
2. Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, the Chinese Academy of Sciences, Guangzhou 510640;
3. Institute of Mineral Resources, the Chinese Academy of Geological Sciences, Beijing 100037;
4. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, the Chinese Academy of Sciences, Beijing 100029 |
| |
| Abstract: | The Lailisigaoer intrusion,located in northwestern Tien Shan,mainly consists of granodiorite porphyry and monzogranite porphyry which share the similar geochemistry characteristics and may be derived from the same source.The zircon Sensitive High-Resolution Ion Microprobe (SHRIMP)U-Pb analyses of the granodiorite porphyry yielded a weighted mean age of 374±4 Ma,indicating that the intrusion emplaced during the Late Devonian.The Lailisigaoer intrusion has high SiO2 contents (67.75% ～74.71%)and K2O/Na2O ratios(1.24～2.20)and all the rocks show a high-K calc-alkaline trend.Chondrite-normalized REE patterns are moderately fractionated (La/Yb)N:(5.25～10.57).They display moderate to weak negative Eu anomalies δEu:(0.55～0.92),with enrichment of LILE and depletion of HFSE.The rocks show low Sr(122×10-6～356×10-6) contents and high Y(17.19×10-6～21.82×10-6)and Yb(1.78×10-6～2.57×10-6)contents.Initial Nd-Sr isotopic compositions for the rocks are ISr=0.707 867～0.709 654 and εNd(t)=-2.79～-1.46.The Pb isotopic ratios for the intrusion are206 Pb/204 Pb=18.423～19.915,207 Pb/204 Pb=15.576～15.685 and 208 Pb/204 Pb =38.344～39.305.All the geochemical data,in conjunction with the geodynamic evidence,suggest that the Lailisigaoer intrusion was most likely generated by partial melting of the Mesoproterozoic crust and the involvement of some mantle components.We propose that the Lailisigaoer intrusion was emplaced in a continental arc setting with southward steep subduction of the Junggar ocean to the Yili-central Tien Shan microplate during the Late Devonian. |
| |
| Keywords: | Zircon SHRIMP U-Pb age Sr-Nd-Pb isotopes Lailisigaoer intrusion Continental arc Northwestern Tianshan |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《地质科学》浏览原始摘要信息 |
| 点击此处可从《地质科学》下载免费的PDF全文 |
|
