| 江西九瑞矿集区硅质断裂磨砾岩带的厘定及其成岩成矿意义 |
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| 引用本文： | 蒋少涌,徐耀明,周巍,朱志勇,孔凡斌,孙岩.江西九瑞矿集区硅质断裂磨砾岩带的厘定及其成岩成矿意义[J].岩石学报,2012,28(10):3076-3086. |
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| 作者姓名： | 蒋少涌 徐耀明 周巍 朱志勇 孔凡斌 孙岩 |
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| 作者单位： | 1. 内生金属矿床成矿机制研究国家重点实验室,南京大学地球科学与工程学院,南京210093
2. 内生金属矿床成矿机制研究国家重点实验室,南京大学地球科学与工程学院,南京210093;江西地质矿产勘查开发局赣西北大队,九江332000 |
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| 基金项目： | 本文受科技部973项目(2012CB416706);"十二五"国家科技支撑计划(2011BAB04B03)和国家自然科学基金面上项目(41072055)联合资助 |
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| 摘 要： | 在九瑞矿集区研究叠合断裂和叠加成矿作用的基础上,我们进一步详细研究了出露在洋鸡山-丁家山-望夫山一线的硅质角砾岩,指出它们不是原先认为的石炭系沉积硅质岩,而应属于一种断裂磨砾岩,并深入探究其形成过程及与成矿之关系.断裂磨砾岩是断裂分带结构成熟的标志之一,多在剪切作用和热液作用下,断裂岩石经硅化-破裂-碎裂-粉碎-研磨,形成具有一定圆度和球度,大小差异较大的磨砾或磨粒,且又会反复的集结-破碎,不断拓宽断裂构造形成磨砾-角砾岩带.本文研究的断裂磨砾岩,呈北东向展布,延长达十几千米.成分上以硅化角砾岩为主,SiO2含量一般大于90％,石英颗粒由隐晶到显晶.一些角砾岩中含Fe2O3较高,有可能是原先的硫化物经氧化形成的褐铁矿.本区洋鸡山-丁家山-望夫山一线产出的断裂磨砾-角砾岩带,很可能是燕山期构造-岩浆-成矿事件的产物.在城门山和武山铜矿,我们之前的工作己发现存在产于泥盆系五通组和石炭系黄龙组层滑构造体系中的黄铁矿角砾岩,则有可能属于海西期同生断裂活动的产物.因此,这些不同的角砾岩具有多阶段活动和叠加成矿的特征.本文还进一步指出,九瑞地区其他层位(如泥盆系与志留系之间、志留系与奥陶系之间)发育的层滑构造体系和断裂角砾岩及热液蚀变岩,也很可能是成矿有利部位,值得今后找矿工作的关注.
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| 关 键 词： | 磨砾 层滑系统 断层结构分带 燕山期构造-岩浆-成矿事件 九瑞矿集区 |
| 收稿时间： | 6/4/2012 12:00:00 AM |
| 修稿时间： | 2012/8/22 0:00:00 |
Discovery of fault-grinding siliceous breccia rock in the Jiurui ore district, Jiangxi Province, and its formation mechanism and mineralization significance |
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| JIANG ShaoYong,XU YaoMing,ZHOU Wei,ZHU ZhiYong,KONG FanBin and SUN Yan.Discovery of fault-grinding siliceous breccia rock in the Jiurui ore district, Jiangxi Province, and its formation mechanism and mineralization significance[J].Acta Petrologica Sinica,2012,28(10):3076-3086. |
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| Authors: | JIANG ShaoYong XU YaoMing ZHOU Wei ZHU ZhiYong KONG FanBin and SUN Yan |
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| Institution: | State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China;Northwestern Jiangxi Geological Team, Bureau of Exploration and Development of Geology and Mineral Researches of Jiangxi Province, Jiujiang 332000, China;State Key Laboratory for Mineral Deposits Research, School of Earth Science and Engineering, Nanjing University, Nanjing 210093, China |
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| Abstract: | Following our previous study on reiterative fault systems and superimposed mineralization in the Jiurui ore district (Jiang et al. , 2010), in this study we conducted a thoroughly investigation on a tectonic-hydrothermal siliceous breccia rock which occurs along the NE trending Yangjishan gold mine-Dingjiashan gold mine-Wangfushan belt. Our study indicates that these siliceous breccia rocks are not sedimentary siliceous rocks in Carboniferous strata as previously thought, but belong to a fault-grinding breccia rock. The rock-forming mechanism of the breccia rocks and their relation to mineralization are also discussed in detail in this paper. Generally speaking, the fault-grinding gravel (grain) include all kinds of boudinage, grinding gravel and cataclastic flow grinding gravel, and it is an indication for maturity of fault zoning texture. Under shearing, the faulted rock may have passed stages of rupturing-fracturing-comminution-grinding and to form a great variety of grinding gravels or grains in different size with appropriate roundness and sphericity. These breccia rocks could have been repeatedly aggregated and fractured, and continuously developed to form a grinding gravel and breccia zone. In the Jiurui ore district, we found that these fault-grinding breccia rocks developed along the main NE-trending structure line of the district and extended tens kilometers long. The breccias are highly silicified with SiO2 contents >90%. The quartz includes both cryptocrystalline and crystalline grains. Some of the breccias contain high Fe2O3 contents, which may indicate presence of primary sulfide ore breccias which have been oxidized to goethite later on. It is likely that these fault rocks were products of Yanshanian tectonic-magmatic-hydrothermal events. In the Chengmenshan and Wushan deposits, we also found various types of pyrite breccias occurring within the Devonian/Carboniferous strata and layer slip fault zone, which may have formed during the Hercynian syn-sedimentary faulting stage. All these different types of breccias composed the ore complex in the district, which show a multiple stage developing feature and superimposed mineralization characteristics. It is also suggested in this paper that the layer slip fault gravel-breccia zones in other sedimentary strata such as the Devonian/Silurian and Silurian/Ordovician at depths are potential mineralization targets that need to pay more attention in future exploration. |
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| Keywords: | Grinding gravel Layer slip system Fault texture zoning Yanshanian tectonic-magmatic-hydrothermal event Jiurui ore district |
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