Based on chemical, spectrographic and X-ray analyses, 34 samples from the experimental Mohole consist of variable proportions of calcite (0-60 percent), biogenic opal (0-50 percent), and normal lithogenous matter (14-97 percent) with an average of 20, 32, and 48 percent, respectively. Contamination with trachytic ash, rhyolitic ash, and saponite and dolomite occurring as alteration products of basaltic material affects the composition of a few samples. Magnesium, manganese, and phosphorus seem to have been derived from basaltic material also. The amounts of barium in the samples seems to be inversely related to sedimentation rates.

From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.

Supplement to: Murata, K J; Erd, R C (1964): Composition of sediments from the experimental Mohole Project (Guadalupe Site). Journal of Sedimentary Research, 34(3), 633-655