Manganese concretions from Kara Sea and Karelia

The determinations of the radioactivity of a series of ferro-manganese concretions of the seas and lakes of the U.S.S.R. (especially of the Kara Sea and lakes of Karelia) have brought out certain facts which make possible the determination of the age of the concretions by the content of radium in its different layers.

Annotated record of the detailed examination of Mn deposits from R/V Tokaidaigaku Maru II Cruise GDP-1 stations

The present paper, deals with the results of the bottom sampling. Sampling devices were a gravity corer for heat flow measurement and dredges of bucket type.

Annotated record of the detailed examination of Mn deposits from DSDP Site 156, Leg 16 (Core 16-156-1)

This site was accidentally spudded on a small basement pinnacle and was abandoned when hard rock was reached within a few meters from the surface. The section penetrated consisted of coarse winnowed calcareous sand over thin chalk ooze resting on a hard crust of ferromanganese oxide presumably covering basalt.

Annotated record of the detailed examination of Mn deposits from DSDP Hole 3-13 and Hole 3-15

The preliminary planning and approach to site 13 were taken from the JOIDES Atlantic Advisory Panel Report and from a previous detailed survey of the site by R/V Vema of the Lamont Geological Observatory. Several CSP profiles crossing the selected site in various directions show an uplifted portion of the sea floor roughly circular in shape of about 10 kilometers in diameter. In contrast to the smooth bottom of the surrounding abyssal plain, the topography of the small rise selected for the site has a small-scale roughness of amplitude of 40 to 80 meters. The work reported here is a biostratigraphic summary of available samples. Only the most important and biostratigraphically significant components of the faunas have been noted. No attempt has been made to give an exhaustive faunal analysis of the samples seen.

(Table 2, page 1376) Chemical analyses of manganese nodules and crusts from the South-western Pacific

Phosphate deposits which apparently formed during the Miocene climatic optimum are widespread on the Chatham Rise and Camp bell Plateau, and on seamounts in the north Tasman Sea. They formed under oxidising conditions by the phosphatisation of older or contemporaneous foraminiferal oozes (Campbell Plateau and Chatham Rise) and coral limestones (Tasman Sea). The phosphorites of the rise and plateau were formed where current activity was sufficiently strong to prevent normal sedimentation, and now form lag deposits. After the Miocene, phosphorite formation ceased and was followed by manganese oxide deposition where conditions were highly oxidising on the eastern Campbell Plateau and north Tasman seamounts, and by glauconite formation in the much less oxidising environments of the western Campbell Plateau and the Chat ham Rise. The manganese deposits are not volcanogenic, as was formerly thought, but formed by slow precipitation from well oxygenated sea water.

Annotated record of the detailed examination of Mn deposits from BLM Leg Alpha Cruise, R/V Kana Keoki off the south-western coastal area of the Gulf of Mexico off Texas

The BLM-OCS (Bureau of Land Management-Outer Continental Shelf) program was designed to establish chemical, biological, and geological baseline on the South Texas Continental Shelf. The focus for the geological program was to establish the nature and amount of the suspended sediment in the water column, of the Holocene sediments on the shelf, and to identify and locate regions of geology conditions which may be hazardous to OCS operations. To accomplish these goals three cruises were planned. The report constitutes results of the first cruise. The results of these cruises associated with the subsequent laboratory analysis, enabled to establish a detailed baseline in order to provide significant geologic and biologic data for environmental assessment. Dredges recovered are available at University of Texas (see: BLM/OCS South Texas Outer Continental Shelf (STOCS) Project Sediment Data http://www.ngdc.noaa.gov/docucomp/page?xml=NOAA/NESDIS/NGDC/MGG/Geology/iso/xml/G02888.xml&view=getDataView&header=none).

(Table 3, page 8) Chemical composition and physical cahracteristics of manganese nodules from the Pacific Ocean

This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values. The paper discloses in a detailed manner the physical and chemical characteristics of nodules, including porosity, surface area, water content and the effect of temperature on crystal structure of major constituents of nodules. In the extraction aspect of nodules, the paper reviews two different extraction schemes revealed in the literature, namely hydrometallurgical treatment and pyrometallurgical treatment. The hydrometallurgical treatments include acid leaching, ammonia leaching, leaching with reducing agents and leaching after high temperature pre-treatments such as in sulfating rousting, while the pyrometallurgical processes include smelting, chlorination-vaporization and segregation. The paper also covers metal recovery processes from leach liquor. An economic survey of processing nodules has been made in terms of problems associated with metal-marketing, and impact of metal production from nodules on mineral industries.

Annotated record of the detailed examination of Mn deposits from R/V Xiang Yang Hong 16 stations (1983) in the Pacific Ocean

Electron microprobe and X-ray diffraction data for north Pacific manganese nodules reveal that the transition metal distributions are controlled by the mineralogy. Microlayers rich in 10Å-manganates generally have high Mn/Fe ratios and positive correlations between Ni, Cu and Mn, and between Co and Fe. Microlayers rich in vernadite, on the other hand, show low Mn/Fe ratios, and Co, Ni and Cu all show positive correlations with Mn. The 10Å-manganates form mainly in porewaters with high Mn/Fe ratios. The Ni2+ and Cu2+ ions are post-depositionally incorporated into the interlayers of the manganates, whereas Co3+ is substituted for Fe3+ in ferric oxyhydroxides. In seawater with a low Mn/Fe ratio, on the other hand, the adsorption of positively charged ferric oxyhydroxides on negatively charged [MnO6] octahedral layers suppresses the growth of 10Å-manganates, enhancing the formation of vernadite. Positively charged hydroxides of Co3+, Ni2+ and Cu2+ are also adsorbed on the [MnO6] layers. These mechanisms of mineral formation and metal uptake are corroborated by data for other oceanic non-hydrothermal manganese nodules and crusts.

(Table 3, Page 417) Table 3. The concentrations of Zn, Cu, Pb, Cd, Ni, Co, Ag, Mn and Fe in a soluble in 1M HCl fraction of ferromanganese nodules of Slupsk Furrow in the southern Baltic sea

The concentration of Zn, Cu, Pb, Cd, Ni, Co, Ag, Mn, Fe, Ca, Mg, K and Na in molluscs Macoma balthica, Mya arenaria, Cardium glaucum, Mytilus edulis and Astarte borealis from the southern Baltic was determined. The surface sediments and ferromanganese concretions associated with the molluscs were also analysed for concentration of these metals. Species- and region-dependent differences in the metal levels of the organisms were observed. The properties of molluscs analysed which have a tendency toward elevated biological tolerance of selected trace metals were specified. The interelement relationship between metal concentrations in the soft tissue and the shell was estimated and was discussed.

Elemental composition of various manganese nodules

Manganese nodules have been observed over wide areas of both the Pacific and Atlantic Oceans, however, deposits in the Pacific Ocean are generally much richer in elements of economic interest such as nickel, copper and cobalt. In understanding the genesis and the geochemistry involved in their formation and growth, it is important to know the total chemical composition of these nodules and how they vary within a given deposit and between deposits in the oceans of the world. The concentrations of elements: nickel, copper, cobalt, iron, manganese, silicon, and calcium, in all of the manganese nodules which have been analyzed were recently summarized by Horn et al. (1972). These observations indicate certain correlations, both positive and negative, between Mn and the associated elements within the nodules. Their data suggest similarities in chemical composition for nodules from a given area; however, the analyses of Mn nodules, like that of the ocean water, itself, has large errors associated with some of the measurements. This is understandable, since many of these measurements were intended to provide an approximate indication of elemental content. Where one is interested in carefully preparing a description of Mn nodule chemical composition which can serve as a basis for formulating theories regarding their genesis and subsequent geochemical changes in the ocean environment, then very precise and accurate analyses are essential. The purpose of this study has been to measure the concentrations of 18 elements in Mn nodules with a high degree of accuracy and determine what correlations exist between element concentrations. The scope of this study was seriously limited and therefore was confined to one area of the Pacific Ocean at approximately 22 N latitude, 114 W longitude, at an ocean depth of approximately 11,000 feet.