陕西汉南毕机沟钒钛磁铁矿锆石U-Pb年代学及其意义

发布时间：2018-03-10 05:37

本文选题：毕机沟　切入点：汉南基性-超基性杂岩体　出处：《地球学报》2017年04期 　论文类型：期刊论文

【摘要】：毕机沟钒钛磁铁矿位于扬子板块北缘汉南杂岩的西北部,是基性-超基性杂岩体分异演化的产物。矿区范围出露的岩石主要包括橄长岩、辉长岩、辉长闪长岩和闪长岩,具有明显岩相分带和韵律旋回特征。目前,已发现的多个钒钛磁铁矿体均位于基性岩-超基性杂岩体的辉长岩相带内。本次研究对毕机沟矿区的含矿辉长岩和穿切含矿辉长岩的花岗岩脉进行了原位微区LA-MC-ICPMS锆石U-Pb定年,获得两者的侵位时间分别为(783±4)Ma(MSWD=0.09)和(759±4)Ma(MSWD=1.50),结果表明毕机沟钒钛磁铁矿的成矿时代大约为783 Ma,但不晚于759 Ma。结合前人区域成果资料,毕机沟含钒钛磁铁矿的基性-超基性杂岩体与该区新元古代大规模具岛弧性质的基性-超基性杂岩体的形成时代相近,我们认为毕机沟钒-钛磁铁矿可能形成于活动型大陆边缘环境。
[Abstract]:Bijigou vanadium titanomagnetite is located in the northwest of the Hannan complex on the northern margin of the Yangtze plate and is the product of the differentiation and evolution of the basic-ultrabasic complex. The rocks exposed in the mining area mainly include olivine, gabbro, pyrodiorite and diorite. Has obvious lithofacies zonation and rhythmic cycle characteristics. At present, Many vanadium titanomagnetite bodies have been found in the gabbro facies belt of the basic rock-ultrabasic complex. In this study, LA-MC-ICPMS zircon U-Pb dating was carried out in situ for the xenoliths and granite veins in the Bijingou ore area. The emplacement time of them is 783 卤4 Ma-MSWD0.09) and 759 卤4m Ma-MSWDU 1.50, respectively. The results show that the metallogenic age of Bijigou vanadium titanomagnetite is about 783 Ma, but no later than 759 Ma. The basic-ultrabasic complex of Bijigou vanadium-bearing titanomagnetite is close to the formation age of the Neoproterozoic large-scale basic-ultrabasic complex with island arc properties in this area. We believe that Bijigou vanadium-titanomagnetite may have been formed in the active continental margin environment.
【作者单位】：中国地质科学院地质力学研究所;北京大学地球科学与空间学院;陕西省地质矿产勘查开发总公司第二分公司;陕西省矿产资源勘查与综合利用重点实验室;
【基金】：中国地质科学院地质力学研究所基本科研费项目(编号:DZLXJK201302) 中国地质调查局地质调查项目“钦杭结合带及邻区深部地质调查”(编号:121201103000150017) 陕西省矿产资源勘查与综合利用重点实验室基金(编号:地合字(2013)第01号)联合资助~~
【分类号】：P597.3;P618.2

【相似文献】