Strontium isotopic ratios in selected microfossils from ODP Holes 119-738C and 120-747A

These interpretations have very different paleoenvironmental implications, but discriminating between them has proved difficult.

To test the competing hypotheses, we measured the 87Sr/86Sr ratios of taxon-specific separates from a number of samples and compared these values both to each other and to expected seawater values at the time of deposition. Our results indicate extensive and pervasive reworking throughout Maastrichtian and lower Danian strata in ODP Hole 738C. We estimate that up to 30% of the mass of foraminifers in any sample can be contributed by individuals that have been reworked.