粤北大宝山矿区船肚岩体和大宝山花岗斑岩锆石LA-ICP-MS U-Pb年龄及多阶段成矿分析

发布时间：2018-09-10 09:25

【摘要】：粤北大宝山矿床矿区出露船肚和大宝山矿化岩体。本文分析了两个岩体矿物组成特征和锆石LA-ICP-MS U-Pb年龄。船肚岩体为似斑状结构,块状构造,主要由似斑状花岗岩、似斑状二长花岗岩及似斑状花岗闪长岩等组成,和云英岩型及矽卡岩型Mo-W矿化紧密共生。大宝山岩体为斑状结构,块状构造,主要由碱长花岗斑岩、普通花岗斑岩、二长花岗斑岩及花岗闪长斑岩组成,矿物组成和船肚岩体的基本相同,和细脉浸染状Mo-W矿化紧密共生。船肚似斑状二长花岗岩和大宝山二长花岗斑岩锆石LA-ICP-MS U-Pb年龄分别为162.1±1.6 Ma,MSWD=2.72和165.8±2.0 Ma,MSWD=1.38。据船肚和大宝山岩体矿物组成基本相同、岩石结构不同及两者锆石Th/U比值不同和U-Pb年龄存在约4 Ma左右时差,提出大宝山矿区在燕山期发生了两阶段岩浆成矿事件,第一阶段岩浆成矿事件发生在166 Ma左右,形成大宝山斑岩型矿床,第二阶段岩浆成矿的形成时间约为162 Ma左右,形成船肚似斑状二长花岗岩及与岩体紧密共生的矽卡岩型和云英岩型矿化;大宝山斑岩体和船肚似斑状岩体是同一岩浆房两次脉动侵入形成的。
[Abstract]:Dabaoshan ore deposit, northern Guangdong Province, the outcrop and the Dabaoshan mineralized rock mass. In this paper, the mineral composition and zircon LA-ICP-MS U-Pb age of the two intrusions are analyzed. The Chuangdu rock body is porphyry structure and block structure, which is mainly composed of porphyry granite, porphyry monzogranite and porphyry granodiorite, and is closely associated with the Mo-W mineralization of the quartzite and skarn types. The Dabaoshan rock body is porphyry structure, massive structure, mainly composed of alkali granitic porphyry, ordinary granitic porphyry, erchanggranitic porphyry and granodiorite porphyry. And vein-impregnated Mo-W mineralization is closely symbiotic. The zircon LA-ICP-MS U-Pb ages of the porphyry monzogranites and the Dabaoshan granitic porphyry are 162.1 卤1.6 Ma,MSWD=2.72 and 165.8 卤2.0 Ma,MSWD=1.38., respectively. According to the same mineral composition, different rock structure, different Th/U ratio of zircon and about 4 Ma time difference of U-Pb age, it is suggested that two stages of magmatic metallogenic events occurred in the Dabaoshan ore area during the Yanshanian period. The first stage magmatic metallogenic event occurred about 166 Ma, forming the Dabaoshan porphyry deposit, and the second stage magmatic metallogenic time was about 162 Ma. The porphyry monzonitic granite and the skarn and quartzite mineralized in close symbiosis with the rock mass, and the porphyry body and the porphyry rock body of Dabaoshan were formed by two pulsating intrusions in the same magma chamber.
【作者单位】：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;广西有色金属集团资源勘查有限公司;中国科学院大学;广西大学资源与冶金学院;广东大宝山矿业有限公司;
【基金】：国家自然科学基金项目(41172080,41372084) 国土资源部深部矿产资源立体探测技术及实验研究(Sino Probe-03-01)联合资助
【分类号】：P597.3;P611

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