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巴伐利亚东北部基岩中所有铀矿化点的上部几乎大部分都呈现有表生再沉积现象。对在再沉积作用中形成的次生铀矿物(硅钙铀矿、铜铀云母、钙铀云母、钡铀云母及镁磷铀云母)用铀-铅法和锾-铀法进行了年龄测定。所有样品都得出不一致的铀-铅年龄。在~(207)Pb/~(206)Pb对~(238)U/~(200)Pb图式中不一致线与一致曲线的上交点仅在某些情况下可看作是原生沥青铀矿的形成年龄,而在所有情况下其下交点都给出了次生铀矿化的年龄。曾获得了0.110±0.006 Ma(用锾-铀法测定)到8.6 Ma的一系列年龄值;这些年龄值可以划分为3组:Ⅰ组包括所有~(330)Th/~(234)U放射性比值低于1的矿物。假定在矿物形成时不存在~(230)Th,则对3个铜铀云母矿化点计算的年龄为1.110—0.164 Ma。Ⅱ组包括那些处于放射平衡状态下(即老于0.4 Ma)的铀矿物,其铀-铅年龄为0—3 Ma。由于下交点精度限制,故得不到更准确的年龄。Ⅲ组包括最老的次生铀矿物,它们的年龄能很好地确定为5.6—8.4 Ma。
Nearly all of the upper part of all uranium mineralization in bedrock of northeastern Bavaria shows the phenomenon of surface redeposition. Age determination of uranium-lead and uranium-bearing uranium for secondary uranium minerals (silicate-uranium ore, copper uranium mica, calcium uranium mica, barium uranium mica and magnesium phosphate uranium mica) formed during redeposition. All samples gave inconsistent uranium-lead ages. The intersection of the inconsistent line with the consistent curve in the ~ (207) Pb / ~ (206) Pb versus ~ (238) U / ~ (200) Pb pattern can only be considered in some cases as a primary pit uranium deposit Age is formed, and in all cases its next intersection gives the age of secondary uranium mineralization. A series of age values of 0.110 ± 0.006 Ma (as measured by the uranium-bearing method) to 8.6 Ma have been obtained; these age values can be divided into three groups: Group Ⅰ includes all radioactive ratios of 330 Th / 234 U Minerals below 1. Assuming that ~ (230) Th does not exist at the time of mineral formation, the age of the three copper uranium mica mineralization sites is calculated to be 1.110-0.164 Ma. Group II includes those uranium minerals that are in a state of equilibrium (ie, older than 0.4 Ma) with uranium-lead ages of 0-3 Ma. Due to the accuracy of the intersection point, there is no more accurate age. Group III includes the oldest secondary uranium minerals, and their ages are well established as 5.6-8.4 Ma.