(Table 1, Page 518) Bulk chemical composition of a ferromanganese crusts from the South-West Pacific

Little is known about the abundance, distribution and origin of the precious metals in marine ferromanganese materials, although it has long been recognized that elements such as silver and gold are frequently enriched in ferromanganese nodules when compared with average crustal abundance. Relative to crustal abundance, silver is enriched in nodules by a factor of between 50 and 100, and for gold enrichment factors of between 100 and 1,000 have been found. The authors report an unusual occurrence of silver and gold in ferromanganese crusts from a back-arc setting in the south-west Pacific; to their knowledge, the first report of material of this kind.