Distribution of Elements in Metalliferous Pacific Sediments Collected during the Deep Sea Drilling Project

BASAL metalliferous sediments on the flanks of actively spreading mid-ocean ridges are thought to be the ancient analogues of modern ridge crest sediments which have moved to their present positions as a result of seafloor spreading1–3. Like ridge crest sediments, they contain high concentrations of several metals such as Mn, Fe, Ni, Cu, Pb and Zn by comparison with normal pelagic clays3. So far most studies on these sediments have included only bulk chemical analyses and little is known about how elements are distributed amongst their principal constituent mineral phases. Such information could be useful in determining both the origin of the deposits and the mechanisms by which elements are incorporated into them. To this end, twenty-three basal sediments collected during legs 5, 7, 8, 9 and 16 of the Deep Sea Drilling Project in the eastern Pacific have been selectively analysed for Mn, Fe, Ni, Co, Cu, Pb and Zn. Sample locations are shown in Fig. 1.