| 粤北大宝山志留纪次英安斑岩年代学、地球化学特征及其地质意义 |
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| 引用本文： | 瞿泓滢,毛景文,周淑敏,陈懋弘.粤北大宝山志留纪次英安斑岩年代学、地球化学特征及其地质意义[J].矿床地质,2019,38(2):331-354. |
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| 作者姓名： | 瞿泓滢 毛景文 周淑敏 陈懋弘 |
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| 作者单位： | 中国地质科学院矿产资源研究所 自然资源部成矿作用与资源评价重点实验室,北京,100037;青海大学地质工程系,青海西宁,8100161 |
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| 基金项目： | 国家自然科学基金项目（编号：41302056）资助 |
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| 摘 要： | 粤北大宝山Cu-Mo-W-Pb-Zn多金属矿床位于钦杭矽卡岩型Cu-Mo成矿带南部。对于该矿床成因目前存在志留纪海底喷流沉积成因和燕山期斑岩矽卡岩成因2种争议。文章以大宝山次英安斑岩为研究对象,通过矿区填图和钻孔编录,查明次英安斑岩与矿体矿化的空间关系;通过年代学、岩石地球化学研究,提示成岩成矿时代与背景;结合区域资料探讨次英安斑岩与金属成矿关系。野外地质填图提示,层状铜矿体赋存在志留系东岗岭下亚组碳酸盐岩中,但存在透闪石化、绿泥石化等与斑岩型矽卡岩型岩体有关蚀变,而且周围发育侏罗纪花岗闪长斑岩;采用LAICP-MS锆石U-Pb同位素精确定年方法,获得次英安斑岩年龄为(434.3±1.0)Ma(DB009)、(431.50±0.12)Ma(DB022)和(417.00±0.87)Ma(DB031)。岩石地球化学数据显示,次英安斑岩为高钾钙碱性系列岩石,具有富集Hf同位素特征和古老模式年龄,指示岩石成因主要源于古老地壳重熔,这种重熔有可能伴生有钨、锡、铌、铊等矿化,但不会产生海底喷流沉积型矿床。结合辉钼矿Re-Os等时线成矿年龄(166.0±3.0)Ma,笔者认为大宝山矿床成矿主要与侏罗纪花岗质岩浆侵位密切相关,与志留纪次火山岩无关。
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| 关 键 词： | 地球化学 辉钼矿Re-Os年龄 LA-ICP-MS锆石U-Pb定年 Hf同位素 大宝山次英安斑岩 |
| 收稿时间： | 2018/10/8 0:00:00 |
| 修稿时间： | 2019/2/10 0:00:00 |
Geochronology and geochemistry of Silurian dacite-porphyry in Daobaoshan deposit, northern Guangdong Province, and its geological significance |
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| QU HongYing,MAO JingWen,ZHOU ShuMin and CHEN MaoHong.Geochronology and geochemistry of Silurian dacite-porphyry in Daobaoshan deposit, northern Guangdong Province, and its geological significance[J].Mineral Deposits,2019,38(2):331-354. |
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| Authors: | QU HongYing MAO JingWen ZHOU ShuMin and CHEN MaoHong |
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| Institution: | MNR Key Laboratory of Metallogeny and MineralAssessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China,MNR Key Laboratory of Metallogeny and MineralAssessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China,Department of Geological Engineering, Qinghai University, Xining 810016, Qinghai, China and MNR Key Laboratory of Metallogeny and MineralAssessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | The Dabaoshan deposit in northern Guangdong Province is a Cu-Mo-W-Pb-Zn polymetallic deposit, located in the southern part of the Qin-Hang porphyry-skarn Cu-Mo ore belt. The genesis of the stratiform copper orebody in the Dabaoshan copper polymetallic deposit has long been a hot topic with two major models, namely, the Silurian submarine volcanic hydrothermal sedimentary model and the porphyry-skarn model. With the Dabaoshan dacite-porphyry rocks as the study object, the authors tried to find out the spatial relationship between the dacite-porphyry and orebody mineralization through mapping and drilling cataloging, bring insight into the epoch and background of magmatism and mineralization by using geochronology and geochemistry, and discuss the relationship between the dacite-porphyry and metallogenesis based on regional geological data. Field geological mapping shows that the stratiform copper orebody occurs in the carbonate strata of the Silurian Donggangling Subgroup with the alteration related to the porphyry-and skarn-type rock bodies, such as tremolite alternation and chloritization, and the development of the Jurassic granodiorite-porphyry around this orebody. LA-ICP-MS zircon U-Pb dating of dacite-porphyry from three samples yielded ages of(434.3±1.0) Ma (DB009),(431.50±0.12)Ma (DB022), and(417.00±0.87)Ma (DB031). The lithogeochemical data show that dacite-porphyry is the high potassium calc alkali rock with the Hf isotope enrichment and ancient model age, and the rock mainly came from the ancient crust remelting with the mineralization of tungsten, tin, niobium, and thallium without the submarine volcanic hydrothermal sedimentation. Combined with the molybdenite Re-Os data(166.0±3.0)Ma, the authors hold that the mineralization of the Dabaoshan deopsit had the relationship with the emplacement of the Jurassic granitic magma but had no relation with the Silurian subvolcanic rock. |
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| Keywords: | geochemistry molybdenite Re-Os data LA-ICP-MS zircon U-Pb dating Hf isotope Dabaoshan dacite-porphyry |
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