Alteration of Deep-Sea Manganese Nodules from the Northern Central Pacific Basin

Manganese nodules from the northern Central Pacific Basin are subjected to chemical and mineralogical analyses as well as mode of occurrence. Under the ore microscope, three different reflectivity zones (high, moderate and low on arbitrary scale) are intermingled in the single ferromanganese oxide layer around the margins of older nodule fragments. The fragments consist mainly of •Ý-MnO2 and amorphous Fe oxyhydroxides referred to as