Tatsumoto M, Hedge C E, Engel A E
Science. 1965 Nov 12;150(3698):886-8. doi: 10.1126/science.150.3698.886.
The average concentrations of potassium, rubidium, strontium, thorium, and uranium in oceanic tholeiitic basalt are (in parts per million) K, 1400; Rb, 1.2; Sr, 120; Th, 0.2; and U, 0.1. The ratio Sr(87) to Sr(86) is about 0.702, that of K to U is 1.4 x 10(4), and of Th to U is 1.8. These amounts of K, Th, U, and radiogenic Sr(87) are less than in other common igneous rocks. The ratios of Th to U and Sr(87) to Sr(86) suggest that the source region of the oceanic tholeiites was differentiated from the original mantle material some time in the geologic past.
大洋拉斑玄武岩中钾、铷、锶、钍和铀的平均浓度(以百万分之一计)分别为:钾,1400;铷,1.2;锶,120;钍,0.2;铀,0.1。锶87与锶86的比率约为0.702,钾与铀的比率为1.4×10⁴,钍与铀的比率为1.8。这些钾、钍、铀以及放射性锶87的含量低于其他常见火成岩中的含量。钍与铀以及锶87与锶86的比率表明,大洋拉斑玄武岩的源区在地质历史时期的某个时候与原始地幔物质发生了分异。