Coupled omega8O-omega3C studies are to be performed on suites of inclusion-bearing diamonds from Jwaneng (Botwana), Kimberley (RSA) and Argyle (Western Australia), locations for which the omega13C values and inclusion mineralogy have been well established. Inclusion omega8O are to be determined using new laser fluorination (LF) technology. omega13C values of diamond hosts will be determined using classical techniques. A detailed LF-omega18O study is to be carried out on a suite of rocks from the East Pacific Rise (17-190S), an ultrafast spreading centre, characterised by intense but localised hydrothermal alteration. The combined study will provide insights into the exchange sea water-oceanic crust and into the recycling of oceanic crust into the deep
sub-continental mantle. With the data we will be able to address the hypothesis that eclogitic xenoliths (and their host diamonds) in kimberlites are ancient recycled oceanic crust.