[MZZ57-01] On-site experiment of hydrogenetic ferromanganese oxide precipitation and absorption for 12-15 years
Keywords:marine manganese minerals, manganese crusts, marine minerals
The on-site precipitation experiment and in-laboratory analysis of precipitation and absorption are those of the direct and simple methods to understand the processes and mechanism. Experiment and observation were carried out in terrestrial environments, soils, hot springs, dessert varnish, meadows, and described from VNS chimneys, though no experiments have been done on the deep-sea floors yet. Such an experiments must prove the morphology and composition of initial products, timing and environment of deposition, and accumulation of useful metallic elements.
The on-site absorption experiments were carried out at the same site for the same time, using artificial Na-buserite (phyllomanganate) chrystals within a membrane-filtered chamber, and variety of metallic elements were absorbed or ion-exchanged. This results indicated metal accumulation take place in a normal deep-sea water after long-time exposure of a Mn oxide mineral.
Considering the global geochemical cycles of Mn and Fe in oceans, the origin and paths of transportation, mechanism of oxidation, and deposition must be understood. The model suggests reconsideration on chemical forms of Mn and Fe in normal sea waters with varying redox potential at the depths. The results ascertained the proposed model of modern continuous precipitation when both Mn and Fe are supplied to ambient underlying waters. The particulate is thus the smallest unique constituent of ferromanganese crust and nodule deposit of the Neogene to modern age at full water depths of oxic deep-sea environments at all oceans. Hydrogenetic particulate, Fe-Mn oxide forms the piled ferromanganese crusts and nodules at a wide-range of depths including OMZ.