(Appendix A3) Geochemistry of ODP Hole 207-1260A

Sediment depth is given in mbsf. The enrichment factors (EF) are calculated as following: EFx = (X/Al)sample : (X/Al)average shale, where X and Al stand for the weight concentration of elements X and Al, respectively. Average shale values are from Taylor and McLennan (1985). Excess SiO2 is calculated as follows: we may consider the fraction of the SiO2 content of the sediment that is in \"excess\" relative to the normative terrigenous content, basing Al values: SiO2xs = SiO2sample - Al2O3sample * SiO2/Al2O3average shale. The excess SiO2 is attributed to biogenic silica. Excess barium is calculated in the same way. The CaCO3 content is calculated from the Ca abundance assuming all the Ca present is under the form of calcite. The samples of the present study are complemented with data from Hetzel et al. (2006).