Micropaleontological Investigations of Pacific Manganese Nodules

Abstract

Micropaleontologic methods have been applied to the study of external and internal structures of Pacific manganese nodules from a few locations. Acid treatment extracted various types of microfossils from the nodules. Direct observations by scanning electron microscope (SEM) confirmed the universal occurrence of microfossils inside of nodule layers, which enabled the biostratigraphic dating of nodules. The SEM observation of nodules and their acid insoluble residues revealed two distinct textures in nodule layers: One was a laminated and appeared to have resulted from the direct precipitation of ferromanganese oxides from sea water, and the other had a massive and chaotic texture in which conspicuous biologic activity was involved.