(Table 2, page 607) Composition of manganese nodules in cores from Leg 16, Deep Sea Drilling Project

Buried manganese nodules or encrustations were encountered at five drill sites of Leg 16. Surface nodules were also sampled at two sites. With few exceptions, nodules within any one drill hole are fairly uniform in composition and are similar in composition to samples obtained previously from the eastern equatorial Pacific. Geochemical and paleontological evidence suggests that at least one of the buried samples was in situ when found and that at least one other was not. The remaining nodules may have fallen from the sediment surface to the positions in which they were found during the drilling process.

Chemical composition of manganese nodules and a ferromanganese crust using different methods

In the 1960s and 1970s, the Kennecott Corporation conducted a number of activities in the evaluation of manganese nodule deposits as well as in their possible hydrometallurgy.

Analysis of manganese nodules in lakes of Scotland

During the "Challenger" Deep-Sea Exploring Expedition a great many peculiar-looking manganese nodules or concretions were dredged from the floor of the ocean at great depths, chiefly in the Red Clay areas of the Pacific. In the present paper we propose to point out the distribution of the oxides of manganese in the geological series of rocks, in fresh and sea water, and in marine deposits, with special reference to our explorations in the lochs of the west of Scotland; to give an account of investigations undertaken to ascertain the source of the manganese present in marine deposits in the form of the higher oxides, and thereafter to discuss the various views that have been advanced to explain the formation and distribution of manganese concretions in marine deposits in general.

Description of manganese nodules and crust collected from the Hakurei Maru Cruise GH76-2, March-May, 1976, in Northwestern Pacific Ocean

The cores and dredges described in this report were taken on the GH76-2 Expedition in March-May, 1976 by the Geological Survey of Japan from the R/V Hakurei Maru. A total of 47 cores and dredges sites have been visited. The survey covered the whole of the Pacific side of the Tohoku Arc, the southern part of the Kurile Arc and the northern margin of the Izu-Ogasawara (Bonin) Arc. The surveyed area covered the continental shelves, slopes, trenches and Pacific basin along the trenches.

(Table XIII-2, Page 166) Physical characteristics of manganese nodules collected in the Pacific Ocean during cruise GH77-1 of R/V Hakurei Maru

In the GH77-1 cruise, manganese nodules were obtained from 31 stations among 37 total ones. Here are reported the preliminary results of the observation mainly done on-board. Special attention was paid to confirming the applicability of the nodule type classification tentatively established in the previous GH76-1 cruise and to delineating the pattern of the nodule distribution and clarifying its relation to the geological factors, such as topography, surface sediment types, and substrate stratigraphy. In addition, a short description of the obtained rock samples from a few stations is included in this chapter.

(Table II, page 668-669) Distribution of elements between minerals soluble in 1M Hydroxylamine hydrochloride (Reducible); in 1m HCL (Acid-soluble) and in the insoluble residue of manganese nodules

Attempts to classify pelagic sediments have been based either on appearance and composition, or on the ultimate origin of the components. In particular it appears feasible to distinguish minerals which crystallized in sea-water from those which formed in magmas, in hydrothermal solution, or by weathering under acidic conditions. It is the case of iron and manganese oxide mineral aggregates which constitute one of the major types of rock encountered on the ocean floor; according to Menard (unpublished) about 10% of the pelagic area of the Pacific is covered by such nodules. The nodules consist of intimately intergrown crystallites of different minerals among those identified, besides detrital minerals and organic matter, are opal, goethite, rutile, anatase, barite, nontronite, and at least three manganese oxide minerals of major importance. Arrhenius and Korkisch (1959) have attempted to separate from each other the different minerals constituting the nodules, in order to establish the details of their structure and the localization of the heavy metal ions. The results demonstrate (Table II) that copper and nickel are concentrated in the manganese oxide phases concentrated in the reducible fraction. Cobalt, part of the nickel and most of the chromium are distributed between these and the acid-soluble group of the non-manganese minerals, dominated by goethite and disordered FeOOH.

(Table 1, page 119) 10Be and 9Be concentrations in manganese nodules of the Pacific Ocean

The usefulness of cosmogenic beryllium-10 (half life = 2.5 Ma) for studying the rates of accumulation of ferromanganese nodules is reported based on its measured depth distribution in the top 20 mm of these deposits. Accumulation rates have been obtained in the range of 1 to 4 mm/Ma, which are in good agreement with rates determined using the 230Th method on the same nodules. The use of 10Be offers promise in extending the dating to the outer few cm of the nodules. This contrasts with conventional methods using 230Th and 231Pa isotopes which, due to their comparatively short half lives, are limited to a few mm at the surface of the nodules. Detailed studies of 10Be in the manganese deposits coupled with other trace element analyses should prove valuable in understanding the processes of formation of these deposits and the chronology of events recorded by them.

Description and analyses of manganese nodules from the South-Western Pacific

Manganese nodules from the Campbell Plateau and Macquarie Ridge have been chemically analysed and their compositions compared with other Pacific nodules. No significant differences in composition are apparent. Foraminifera from nodule nucleii are late Tertiary or Quaternary, indicating the late geological formation of manganese nodules in this region. Nodule formation may be related to late Tertiary or Quaternary submarine volcanism.

(Table 12-4, page 360) Percentage loss of water from manganese nodules (on a wet basis) at different temperatures

This chapter discusses the formation and distribution of some metals in ocean-floor manganese nodules in the light of the observed data in the literature and thermodynamic and kinetic considerations of the oxidation of metal ions in the oceanic environment. There are, in general, two major schools of thought on the mechanism of incorporation of the minor elements such as nickel, copper, and cobalt with the major elements such as manganese and iron. One is the lattice substitution mechanism and the other the adsorption mechanism. If the mechanism is lattice substitution, extraction of the metal ions is not possible unless the lattice of the major elements is first broken and exchanged with other ions from the bulk solution. Consequently, the leaching behavior of minor elements should display a very close relationship with that of major elements.