Geochemistry at DSDP Holes 68-501 and 70-504B

There are also systematic deviations from the mean for some of the oxides analyzed by the laboratories (Table 7). The deviations from the mean do not represent deviations from "correct" values, since the calculated mean is based on only 8 analyses. However, they make it clear that care must be taken when data from one laboratory are compared with data from another.

Furthermore, they indicate that these data, which were produced as routine analyses, must be considered to have a larger uncertainty than previous data on standard shipboard samples. Differences between different laboratories of 1.5% in SiO2, 1% in Al2O3, 1% in FeO*, 0.6% in CaO, 0.5% in MgO and 0.5% in Na2O are larger than satisfactory, in our opinion, even for routine analyses.