Controls of eustasy and diagenesis on the 238U/235U of carbonates and evolution of the seawater (234U/238U) during the last 1.4 Myr

Using a leaching protocol designed for the study of U isotopes in recent carbonates, we measured the U isotope composition, both 238U/235U and 234U/238U, of modern and ancient corals (n = 6), a limestone and a dolostone, as well as 43 shallow-water carbonate sediments from the ODP Leg 166 Site 1009 drill core, on the slope of the Bahamas platform. Although bulk corals record the seawater δ238U value within ±0.02‰, differences of up to 0.30‰ in...