论文部分内容阅读
从白云鄂博超大型稀土-铌-铁矿床的切割稀土矿化且与重晶石共生的晚期黄铁矿脉中,选取6个黄铁矿样品,对其进行了Re-Os定年,结果表明它们分别含有16~30ngRe和0.10~0.16ngOs,给出加里东期的439±86Ma等时线年龄.样品的高Re/Os比值和低含量高放射成因Os的组成特性支持这组黄铁矿样品为表壳构造成因.构造演化历史表明,华北地块北缘在早古生代属于被动大陆边缘,而不是具有大量火山岩浆活动的俯冲带.本次工作提供了一个新的证据,支持白云鄂博矿床在加里东期经历了地壳成因的热扰动事件,而使部分同位素体系记录了加里东期的扰动年龄,而不是主要成矿期的年龄.
Six pyrite samples were selected from the late pyrite mineralization of the rare earth-Niobium-ultramafic rare earth-niobium-iron deposits in Bayan Obo and reconstructed with barite, and the Re-Os dating of these pyrite samples was carried out. The results show that They contain 16 to 30 ng Re and 0.10 to 0.16 ngOs, respectively, giving an isochron age of 439 ± 86 Ma for the Caledonian period.The high Re / Os ratio of the sample and the low content of high radiogenic Os contribute to this group of pyrite samples The tectonic evolution history shows that the northern margin of the North China block belonged to the passive continental margin in the Early Paleozoic, rather than to a subduction zone with volcanic magma activity. This work provides a new evidence to support the Bayan Obo deposit in The Caledonian experienced thermal perturbations of the crustal genesis, leaving some isotope systems to record the disturbance age of the Caledonian, rather than the age of the major mineralization.