Sugisaki et al.(1991)による〔『Manganese carbonate bands as an indicator of hemipelagic sedimentary environments』(23p)から〕


Two contrasting patterns of Mn distribution emerged from geochemical examination of marine cores in several regions. Uniformly abundant Mn is contained in sediments from pelagic open oceans, while in hemipelagic regions, Mn is often concentrated in several specific horizons and is associated with CO2. Mn carbonate layers, designated as “manganese bands” in this paper, occur typically in hemipelagic sediments; carbon isotopic data show that the possible source of the carbonates is organic material supplied to hemipelagic regions from nearby lands. Ancient analogs of the present-day manganese bands were found to occur in shale and chert within the Paleozoic-Mesozoic Mino terrane of central Japan. Manganese bands, consisting largely of rhodochrosite, are characterized by higher contents of P, Ba, and some heavy metals and a lower ratio for Zn/Co, compared with the ambient rocks. This suggests that manganese bands formed under suboxic conditions where organic materials are oxidized to supply CO2 necessary for the carbonate formation. Some manganese bands, particularly those hosted by chert, are characterized by extremely light carbon isotopes; this may result from methane-derived CO2. Furthermore, manganiferous schists, such as piemontite-quartz schist in the Sambagawa terrane, can be correlated to the chert with manganese bands in the Mino terrane. On the basis of the several lines of evidence obtained here, forearc and back arc basins like the Sea of Japan and rifted continental margins with narrow basins such as the Gulf of California are possible tectonic settings that are modern analogs to the Paleozoic-Mesozoic complex in the Japanese Islands.』

Distribution patterns of Mn in marine sediments
Manganese bands on land

General characteristics of manganese
High phosphorus character of manganese bands
Trace element features
Genesis of manganese bands
Geological significance of manganese bands

Origin of chert
Depositional site of the Mino Terrane strata
Manganiferous schist vs. manganese band
Referenced cited