A sediment core obtained from the northeastern Philippine Sea Basin was analyzed for 232Th, 230Th, 226Ra and 210Pb. Three sheets of Ferro-manganese oxide in a matrix of red clay were included in the 73 m core. Although the concentration of 232Th of land origin is normal as compared with that of the usual red clay or of the sediment obtained at the neighboring station, the concentration of radiogenic 230Th is extremely low and does not decrease with increasing depth. The radioactivity of rather soluble 226Ra at the station is not less than that of 230Th in the surface sediment, showing a tendency different from that observed in usual cores. Some enrichment in the comparatively short-lived 210Pb activity relative to 226Ra activity was found in the top sediment and in the first ferro-manganese sheet at the station. If the excess 210Pb in the ferro-manganese sheet is not due to contamination of the surface sediment, lead should migrate through the sheet. These facts suggest that the core has not been accumulating during the past few hundred thousand years or more.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Tsunogai, Shizuo; Yamada, M (1980): A radiochemically studied sediment core from the Philippine Sea Basin indicating no accumulation during the past few hundred thousand years. Geochemical Journal, 14(1), 19-26