The regional patterns in distribution and composition of deep-sea mineral deposits are characterized in relation to geological setting in the NW Pacific, based on compilation of geological and geochemical data for ferromanganese crusts and nodules, massive polymetallic sulfide, and phosphorite. The mapping and simple statistics singled out some regions of possible economic interest; high Co-Ni-Pt crust/nodule deposits on seamounts of the Pacific plate and less-grade similar type deposits over the remnant arcs of the Philippine Sea plate. Some of massive polymetallic deposits located in plate boundaries show high-precious metal contents, which await more detailed investigations in earth science and economic evaluation. This study emphasizes Importance of geological consideration in exploitation and mining technology.
Discoveries of marine metallic ore deposits during the last two decades have motivated geoscientific investigations and economic explorations in the central and eastern Pacific (Fewks et aI., 1980; Halbach et aI., 1988; Kohpina and Usui, in press). The manganese nodule (referred to as MnN) provinces of the northeast equatorial Pacific have been well documented in the aspects of economical evaluation and geology. Secondly, cobalt-rich manganese crusts (referred to as MnC) were first reported in the central Pacific seamount areas by the German and U.S.A. geologists group in the early 1980" s (Halbach et aI., 1982). The third type is the recent active massive polymetallic sulfide (referred to as MPS) deposits which was first observed by a French submersible in the spreading centers along the East Pacific Rise (e.g., Ballard et at, 1981), and similar types are being found also in the south Pacific and Atlantic Oceans (Rona and Scott, 1993). In the northwest Pacific region little has been known of general distribution patterns of these types of deposits, since few systematic research cruises on marine minerals have been undertaken.
