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 Sr87 to Sr86 is about 0.702, that of K to U is 1.4 x 104, and of Th to U is 1.8. These amounts of K, Th, U, and radiogenic Sr87 are less than in other common igneous rocks. The ratios of Th to U and Sr87 to Sr86 suggest that the source region of the oceanic tholeiites was differentiated from the original mantle material some time in the geologic past.
|Title||Potassium, rubidium, strontium, thorium, uranium, and the ratio of strontium-87 to strontium-86 in oceanic tholeiitic basalt|
|Authors||M. Tatsumoto, C. E. Hedge, A.E.J. Engel|
|Publication Subtype||Journal Article|
|Record Source||USGS Publications Warehouse|