Manganese nodules also called polymetallic nodules, are spherical rock concretions formed at the bottom of the sea. Due to their high polymetallic content, they are discussed as a natural resource.
Blake Plateau, Atlantic Ocean,31°02' N,78°22' W, depth 788 meters
Major components are MnO (24 %m/m), FeO (14.5 %m/m) and CaO (15 %m/m).
Transition metals are enriched (500-5000 µg/g).
Most trace elements and REEs are in the 10-500 µg/g range.
|original certificate of analysis||Link|