Metal content of ferromanganese seamount crusts from the Central Pacific taken during the research cruise Midpac 81

The ferromanganese crust samples studied have been taken from Central Pacific seamount areas during the research cruise Midpac 81. Two ferromanganese crust generations with different ages have been identified; in between a period of carbonate sedimentation and an episode of phosphorite formation have taken place. The older crust generation, therefore, is mostly impregnated by carbonate-apatite. The younger crust generation has started to accumulate around 10 Ma ago, the growth period of the older crust layer is most likely Middle Eocene to Early Oligocene. Metal concentration was determined by Atomic Absotption Spectrophometry. For Pt a chemical pre-enrichment step (e.g. enrichment by coprecipitation with tellurium) was necessary.