安徽庐枞矿集区金鸡山岩体成岩年代学及其地质意义  

Chronology of the Jinjishan pluton in the Lu-Zong ore cluster,Anhui Province and its geological implications

作　　者：魏国辉[1] 张舒[1] 张赞赞[1] WEI Guo-hui;ZHANG Shu;ZHANG Zan-zan(Geological Survey of Anhui Province(Institute of Geological Sciences of Anhui Province),Hefei,Anhui 230001,China)

机构地区：[1]安徽省地质调查院(安徽省地质科学研究所),安徽合肥230001

出　　处：《安徽地质》2022年第2期97-100,共4页Geology of Anhui

基　　金：安徽省公益性地质工作项目“安徽省庐枞地区与碱性岩有关的铀(钍)矿调查评价”(编号:2016-g-1-7),“安徽省稀有、稀散元素矿产远景调查”(编号:2016-g-2-16)联合资助。

摘　　要：金鸡山岩体侵位于庐枞盆地东南缘的A型花岗岩带内。详细的岩相学工作显示,金鸡山岩体岩性为石英正长斑岩。LA-ICP-MS锆石U-Pb测年结果显示,金鸡山岩体形成于(129.8±0.6) Ma,属于长江中下游成矿带伸展构造体制下的岩浆活动产物。庐枞盆地东南缘的A型花岗岩主要由正长岩类与花岗岩类组成,正长岩类(131~126 Ma)的形成时代稍早于花岗岩类(128~124 Ma)。结合区域高钾钙碱性侵入岩和橄榄安粗质火山岩的研究成果,本文认为131~124 Ma广泛发育的A型花岗岩代表了长江中下游地区已进入伸展构造的高峰期。The Jinjishan pluton was emplaced in the A-type granite belt in the southeastern margin of the Lu-Zong Basin and has been confirmed as quartz syenite porphyry by detailed petrographic study. LA-ICP-MS zircon U-Pb dating indicates that the pluton was formed at(129.8 ± 0.6) Ma as a product of magmatic activity under the extensional tectonic regime along the middle-lower Yangtze metallogenic belt. The A-type granite belt is mainly composed of syenite and granite, and the syenite(131~126 Ma) is slightly older than the granite(128~124 Ma).According to the results of research into the regional highK calc-alkaline intrusive rocks and shoshonitic volcanic rocks, it is suggested that the A-type granite, widely developed in 131~124 Ma, represents the most active period of the extensional tectonics in the middle-lower reaches of the Yangtze River.

关 键 词：金鸡山岩体 A型花岗岩 锆石U-PB年龄 庐枞矿集区 

分 类 号：P597[天文地球—地球化学]