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根据古地磁法,犹他州里斯本谷背斜二叠纪Cutler组红层内的铀矿床测得一近似年龄。这一结果与北美其它下二叠纪地层和科罗拉多高原处的Cutler组的结果极其相似。在未矿化砂岩中,稳定剩余磁化强度主要由沉积期后假象赤铁矿或碎屑成因引起;而对于矿化砂岩,稳定剩余磁化强度则主要由裂隙中一群含铀和含钠的自生镜赤铁矿引起,因此它可以表示矿化的时间。这些成果并结合里斯本谷区构造发育及附近三叠纪ChiMe组中铀矿床的资料,表明在晚白垩纪至早或中第三纪时期里斯本谷背斜的发育促使了Chinle组中矿体的氧化分解作用,导致其中的铀和铁进行再分配而进入Cutler组内。Chinle组中矿体硫化矿物在分解阶段生成的酸性溶液,可以说明Cutler主岩层中假象赤铁矿部分溶解以及大量铀和铁的同时迁移。这些溶液经过与主岩组分特别是方解石反应而被中和,使非晶质Fe_2O_3沉淀,经过吸附作用併入铀,并随着时间而形成镜赤铁矿。
According to the paleomagnetic method, an approximate age was measured for uranium deposits within the red beds of the Permian Cutler Formation in the Lisbon Valley anticline, Utah. This result is very similar to the results of the Cutler Formation at other Lower Permian formations and the Colorado Plateau in North America. In unmineralized sandstones, the stable residual magnetization is mainly caused by the artifact hematite or detritus after sedimentary period. For the mineralized sandstone, the stable residual magnetization is mainly composed of a group of uranium-bearing and sodium-containing automicroscopy in the fracture Hematite causes, so it can indicate mineralization time. These results, combined with the tectonic development of the Lisbon Valley and the uranium deposits in the Triassic ChiMe Formation in the vicinity, suggest that the development of the Lisbon valley anticline during the Late Cretaceous to early or middle Tertiary prompted the oxidation of ore bodies in the Chinle Formation Decomposition, which led to the redistribution of uranium and iron into the Cutler group. The acidic solution generated by the sulfide mineral in the Chinle Formation at the decomposition stage can explain the partial dissolution of artifact hematite and the simultaneous large amount of uranium and iron migration in the Cutler main rock. These solutions are neutralized by reaction with the host rock components, especially calcite, to precipitate amorphous Fe_2O_3, incorporate it into the uranium by adsorption, and form the hematite over time.