South of Glitrevatn (Lake Glitre), 40 km NNW from Oslo (formerly Kristiania), lies an important intrusive quartz-porphyry formation as part of the Drammen granite massif. In all the valley lowlands cutting out of this formation and leading to Glitrevatn, one finds important deposits of manganese rich bog ore. On the relief upstream side, these deposits are overlain by a moraine talus made of debris originated from the granitic formation. The deposit itself is two to three meters thick and made internally of an alternance of iron and manganese rich layers. The author has made the hypothesis that the granitic formation is the source of the metals.

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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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.