Determination of the lithium isotopic composition of planktic foraminifera and its application as a paleo-seawater proxy

The first measurements of seawater δ7Li from the Indian Ocean average 33.0 ± 1.2‰ (2σ) throughout the water column. This value is within error of values previously reported for the Atlantic and Pacific Oceans as is expected based on the long mean residence time of Li in the ocean. There is no evidence for a significant decrease in Li/Cl ratios, as reported by some workers, with Indian Ocean waters averaging 9.10 ± 0.11 μg/g.