Environment & Energy

the full text of the paper, which is from 2000, so it's not AI, to see what's going on. Probably a misprint. I may not have time until I return from a business trip to a conference, so if I forget, remind me. (I'm writing during a brief sleep interruption.)

There is some isotope fractionation - obviously not on a scale to justify these numbers - in the oceans, because the ²³⁴Th, (t_1/2 = 24.1 days) is completely insoluble in water, as are U(IV) compounds. If this were not true, thorium was not insoluble, thorium might be as sustainable as uranium is. The latter is the reason that there were no reactors like the OKlo natural reactors until oxygen appeared in Earth's atmosphere. Many people believe - they're wrong - that thorium is more sustainable than uranium. There is, however, no water driven geochemical thorium cycle, although terrestrial thorium is more available than terrestrial uranium.

In general, in rock, the secular equilibrium between sup]234U/sup]238U is on the order of 10^-6. Displacement from secular equilibrium can be utilized in recording the geological history of a uranium source.

There are actually a lot of these riverine uranium content tables in a lot of papers, but I had this one in a file format that was convenient to post.