论文部分内容阅读
从新墨西哥州西北部晚侏罗纪莫里森组和白垩纪的达科他、曼科斯组中采集了近200个砂岩和页岩的样品,用仪器分析和缓发中子活化分析方法,对这些样品进行了全岩和粘土粒级部分的稀土总量、铀和钍的含量测定。各组中元素的总分布趋势表明稀土和钍的含量,随着地质年代变新而逐渐增加。在列
Nearly 200 sandstone and shale samples were collected from the Late Jurassic Morrison Formation in the northwestern New Mexico and the Dakota and the Mankesh Formation in the Cretaceous. Instrumental analysis and delayed neutron activation analysis were performed on these samples The whole rock and clay fractions of the total rare earth, uranium and thorium content determination. The trend of the total distribution of elements in each group shows that the contents of rare earth and thorium increase gradually with the change of geological age. In the column