Measurements of K, Rb, U, Sr and Pb in diamonds containing inclusions

KNOWLEDGE of the Pb and Sr isotopic compositions of syngenetic inclusions in diamonds is important for several reasons. As diamonds probably crystallised at depths of more than 100 km, the isotopic data may provide constraints on the mode of the geochemical evolution of the Earth. It may also be possible to test assumed U/Pb ratios (U/Pb=μ) for the mantle and to estimate the age of particular diamonds. Diamonds are particularly appropriate for these studies because, in contrast to kimberlites and their associated nodules, any contamination by crustal material can be overcome by washing in acid.