赣南岐山岩体深熔-幕式岩浆活动:来自锆石U-Pb精细年代学研究

发布时间：2018-04-30 20:00

本文选题：岐山岩体 + 加里东运动　；参考：《地质学报》2017年04期

【摘要】：武夷山地区加里东期深熔混合岩化-岩浆作用普遍,且两者时代一致或相近,但是加里东期深熔作用的启动时间尚不明确。赣南寻乌县岐山岩体位于武夷山构造带南部,该岩体形成时代缺乏精确的年代学依据。基于锆石LA-ICP-MS U-Pb测年手段,在该岩体中发现两期锆石,早期锆石为深熔成因,晚期为岩浆成因。本次研究获得的晚期锆石形成时代为445~440Ma,具有从外向内年龄渐新的规律,表明该岩体形成于晚奥陶世晚期-早志留世,可能是从源区上升的不同批次岩浆就位的结果,即该岩体为加里东期深熔-幕式、多期次岩浆活动的结果。边缘部位与岩体中心部位分别获得早期深熔锆石加权平均年龄值(458±4Ma)与岩浆锆石加权平均年龄值(460±4Ma),两者在误差范围内一致。表明武夷山地区在加里东早期,大约460Ma左右发生了一期深熔-岩浆活动,为武夷山构造带加里东运动深熔作用的启动时代提供了制约。
[Abstract]:The Caledonian melting-magmatism is common in Wuyishan area, and the two ages are the same or similar, but the starting time of Caledonian deep melting is not clear. The Qishan rock body in Xunwu County is located in the south of Wuyishan structural belt. Based on the zircon LA-ICP-MS U-Pb dating method, two phases of zircon have been found in the body. The early zircon is of deep melting origin and the late stage is magmatic origin. The late zircon age obtained in this study is 445,440Ma. it has a new age from outer to inner, which indicates that the body was formed in late Ordovician and early Silurian, which may be the result of different batches of magma rising from the source area. It is the result of the Caledonian deep-melt-curtain-type and multi-stage magmatism. The weighted mean age of early melting-zircon (458 卤4MaA) and magmatic zircon (460 卤4MaA) were obtained at the edge and the center of the rock body, respectively, which are consistent with each other in the error range. It is suggested that a period of deep melt magmatic activity occurred around 460Ma in the early period of Caledonian movement in Wuyishan area, which restricted the initiation of the Caledonian movement in the Wuyishan tectonic belt.
【作者单位】：中国地质科学院矿产资源研究所;江西省地质调查研究院;
【基金】：中国地质调查局地质调查项目(编号:12120113071600)资助的成果
【分类号】：P597.3;P588.11

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