| 大陆岩石圈伸展与斑岩铜矿成矿作用 |
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| 引用本文： | 李晓峰,华仁民,马东升,徐净,张龙,齐有强,武丽艳,朱艺婷.大陆岩石圈伸展与斑岩铜矿成矿作用[J].岩石学报,2019,35(1):76-88. |
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| 作者姓名： | 李晓峰 华仁民 马东升 徐净 张龙 齐有强 武丽艳 朱艺婷 |
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| 作者单位： | 中国科学院矿产资源研究重点实验室中国科学院地质与地球物理研究所;中国科学院地球科学研究院;中国科学院大学地球与行星科学学院;南京大学地球科学与工程学院;中国科学院地球化学研究所 |
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| 基金项目： | 本文受国家自然科学基金项目（41472080、41272112）资助. |
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| 摘 要： | 华南地区自古生代以来一直属于陆内构造演化环境。华南陆内伸展型斑岩铜矿主要形成于早侏罗世、晚侏罗世和早白垩世3个时期,其中晚侏罗世成矿期与华南中生代大规模钨锡成矿作用的形成基本属于一个时期。这些斑岩型矿床的时空分布与同时期的俯冲带在时间上和空间上具有明显不协调的关系,且与俯冲有关的、后俯冲伸展背景以及陆陆碰撞有关的斑岩铜矿的线性分布特点明显不同,尤其是早白垩世斑岩铜矿的分布明显呈面状分布,与华南中生代地壳明显减薄的区域基本一致。虽然这3个时期的斑岩型铜矿在地球化学上显示出弧岩浆岩的特点,但是地质事实证明在这3个时期,华南岩石圈发生了明显的伸展作用,尽管每个时期华南不同地区岩石圈伸展的程度可能不同。因此,我们把华南这种类型的斑岩铜矿归称之为"陆内伸展型"斑岩铜矿。陆内伸展型斑岩铜矿的成矿机制可能是岩石圈伸展背景下软流圈上涌导致陆下岩石圈地幔或者下地壳被改造有关。
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| 关 键 词： | 岩石圈伸展 软流圈上涌 岩石圈地幔 斑岩成矿 华南 |
| 收稿时间： | 2018/9/1 0:00:00 |
| 修稿时间： | 2018/11/15 0:00:00 |
Mesozoic sub-continental lithospheric mantle extension and related porphyry copper mineralization in South China |
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| LI XiaoFeng,HUA RenMin,MA DongSheng,XU Jing,ZHANG Long,QI YouQiang,WU LiYan and ZHU YiTing.Mesozoic sub-continental lithospheric mantle extension and related porphyry copper mineralization in South China[J].Acta Petrologica Sinica,2019,35(1):76-88. |
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| Authors: | LI XiaoFeng HUA RenMin MA DongSheng XU Jing ZHANG Long QI YouQiang WU LiYan and ZHU YiTing |
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| Institution: | Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China;College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China,School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China,School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China,Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China,Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China;College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China,Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China,Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China and Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China;College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Most of the large porphyry copper deposits occurred in arc setting, which are closely related to oceanic crust subduction, especially to partial melting of mantle materials caused by dehydration of subducted plates. Recent studies have shown that porphyry copper deposits can occur in non-subduction setting, such as intra-continental and continental collision setting. The formation of porphyry copper deposits in continental collision setting is related to the partial melting of lithosphere modified by subduction. The fertilized magma emplaced in the shallow part of the crust through the crystallization differentiation and crustal contamination. However, the spatial and temporal distribution of porphyry copper deposits in the intra-continents setting are incompatible with the structures of the contemporary subduction zones, its genesis mechanism and dynamic process are not very clear. It has been a long intra-continental tectonic setting since the Paleozoic in South China. Three episodes porphyry copper systems (Early Jurassic, Late Jurassic and Early Cretaceous) occurred in Mesozoic, which related to the intra-continental tectonic setting. The Late Jurassic porphyry copper system was concurrent with the large-scale W-Sn mineralization in South China. The spatial and temporal distributions of these porphyry deposits are obviously inconsistent with those of the subduction-related porphyry copper system in southwestern USA and Cordilleran orogenic belt. The characteristics of sub-continental lithospheric mantle extension-related porphyry copper deposits is quite different from those occurred as linear formed in subduction, post-subduction extension, and continental collision setting. Especially, the porphyry copper deposits in the Early Cretaceous porphyry copper deposits which distributed as planar, which basically consistent with Mesozoic crustal thinning area in South China. Although the porphyry copper deposits of these three periods show arc magma affinity in geochemistry, the Nd-Sr isotope of the porphyries indicate the contribution of mantle to mineralization vary from the regions and the metallogenic types. The geological facts prove that the lithosphere of South China has undergone obvious extension during these three periods. The extent of lithospheric extension may vary in different regions of South China in each period. Therefore, we called the porphyry copper deposit from these three episodes as "intra-continental extensional porphyry copper deposit". The metallogenic mechanism of the Mesozoic intra-continental extensional porphyry copper deposits may be related to the upwelling of asthenosphere under the lithospheric extension background, which resulting in the transformation of the subcontinental lithospheric mantle or lower crust. |
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| Keywords: | Sub-continental lithosphere extension Asthenosphere upwelling Lithosphere mantle Porphyry copper South China |
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