| 广东省河台金矿区糜棱岩锆石LA-ICP-MS U-Pb年龄及其地质意义 |
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| 引用本文： | 焦骞骞,许德如,陈根文,陈延生,张建岭,高亦文,于亮亮,邹少浩.广东省河台金矿区糜棱岩锆石LA-ICP-MS U-Pb年龄及其地质意义[J].岩石学报,2017,33(6):1755-1774. |
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| 作者姓名： | 焦骞骞 许德如 陈根文 陈延生 张建岭 高亦文 于亮亮 邹少浩 |
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| 作者单位： | 中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640;中国科学院大学, 北京 100049;中南大学有色金属成矿预测教育部重点实验室, 长沙 410083,中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640,中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640,广东省地质局第五地质大队, 肇庆 526600,中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640;中国科学院大学, 北京 100049,广东省地质局第五地质大队, 肇庆 526600,中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640;中国科学院大学, 北京 100049,中国科学院广州地球化学研究所, 中国科学院矿物学与成矿学重点实验室, 广州 510640;中国科学院大学, 北京 100049 |
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| 基金项目： | 本文受国家重点研发计划重点专项（2016YFC0600401）、中南大学有色金属成矿预测教育部重点实验室开放基金项目（2016YSJS003）和中国地质调查局项目（12120114052801）联合资助. |
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| 摘 要： | 河台金矿区位于广东省高要市境内,普遍认为其是典型的韧性剪切带型金矿。本次对采自韧性剪切带中的糜棱岩和初糜棱岩样品进行了LA-ICP-MS锆石U-Pb定年,以约束剪切带的活动时代,并为金矿化事件提供依据。利用糜棱岩中的热液锆石约束韧性剪切带的变质变形时间,获得两组年龄:糜棱岩中热液锆石增生边加权平均年龄约为240Ma,代表左旋运动的年龄;初糜棱岩中热液锆石加权平均年龄约为204Ma,代表右旋运动的年龄。因此,矿区在印支期可能经历过两期剪切变形,并且这两期变形事件在整个华南都是普遍存在的。结合前人对矿化时间的研究,河台金矿的成矿时间(燕山期)要晚于韧性剪切带的形成时间(印支期)。样品中继承性锆石(糜棱岩中核部锆石)年龄显示云开群最晚沉积时间为早古生代早期,而并非前寒武地层。另外,本次研究还测试了锆石的Lu-Hf同位素,实验表明,可以根据热液锆石与继承性锆石的Lu-Hf同位素关系,判定热液锆石的形成条件。云开群的成岩物质主要来自1.8Ga地壳增生事件所形成的地壳物质发生重熔而产生的岩浆岩。
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| 关 键 词： | 糜棱岩 热液锆石 LA-ICP-MS锆石U-Pb定年 Lu-Hf同位素 河台金矿 广东 |
| 收稿时间： | 2016/1/2 0:00:00 |
| 修稿时间： | 2016/11/20 0:00:00 |
Zircon LA-ICP-MS U-Pb age of mylonite in the Hetai goldfield, Guangdong Province of South China and the geological implication |
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| JIAO QianQian,XU DeRu,CHEN GenWen,CHEN YanSheng,ZHANG JianLing,GAO YiWen,YU LiangLiang and ZOU ShaoHao.Zircon LA-ICP-MS U-Pb age of mylonite in the Hetai goldfield, Guangdong Province of South China and the geological implication[J].Acta Petrologica Sinica,2017,33(6):1755-1774. |
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| Authors: | JIAO QianQian XU DeRu CHEN GenWen CHEN YanSheng ZHANG JianLing GAO YiWen YU LiangLiang and ZOU ShaoHao |
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| Institution: | CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;University of Chinese Academy of Sciences, Beijing 100049, China;MOE Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Central South University, Changsha 410083, China,CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China,CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China,The 5th Brigade of Guangdong Geological Bureau, Zhaoqing 526600, China,CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;University of Chinese Academy of Sciences, Beijing 100049, China,The 5th Brigade of Guangdong Geological Bureau, Zhaoqing 526600, China,CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;University of Chinese Academy of Sciences, Beijing 100049, China and CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | The Hetai goldfield, located in Gaoyao area of Guangdong Province of South China, is a typical ductile shear related gold deposit. LA-ICP-MS U-Pb zircon dating on hydrothermal origin zircons from mylonite and protomylonite were carried out to constrain the metamorphism and deformation times of ductile shear zones, further to reveal the role of mylonitization in gold mineralization. Two weighted mean ages were obtained: an early sinistral ductile shearing at ca.240Ma suggested by the hydrothermal zircon rims from mylonite; and a late dextral ductile-brittle shearing at ca.204Ma suggested by the hydrothermal zircon grains from protomylonite. Therefore, the Hetai goldfield was subjected to two Indosinian shearing events that are also common in South China. Given the published geochronology data of the Hetai goldfield, the gold mineralization ages (Yanshanian) significantly postdate the ductile deformation. The inherited zircons (the zircon cores) from the mylonite suggest that the Yunkai Group formed in early stage of Early Paleozoic rather than Precambrian. Moreover, it may be possible to determine the forming mechanism of hydrothermal zircon based on the distinction of Lu-Hf isotope between the hydrothermal and inherited zircon. The compositions of the Yunkai Group are associated to the magmatite that may have been derived from the remelting of 1.8Ga earth crust. |
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| Keywords: | Mylonite Hydrothermal zircon LA-ICP-MS U-Pb zircon dating Lu-Hf isotope Hetai gold deposit Guangdong Province |
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