The234U238U ratio in diatom oozes from South West Africa shelf is as high as 1.175±0.008 being slightly lower in enclosed phosphatic nodules - 1.163±0.005 and still lower in similar nodules from Chile shelf - 1.143±0.008. The absolute age calculated after these data is (24(±27)·103years for the South West African nodules and 55(±35)·103years for the Chilean nodules. © 1972.
Baturin, G. N., Merkulova, K. I., & Chalov, P. I. (1972). Radiometric evidence for recent formation of phosphatic nodules in marine shelf sediments. Marine Geology, 13(3), 37–41. https://doi.org/10.1016/0025-3227(72)90085-0