Marine manganese deposits / Морские месторождения марганца

One of the earliest records, if not the earliest, of iron-manganese concretions relates to the form of soil nodules appropriately known as “buckshot gravel” and is given by Liechhardt (1847; quoted in Bryan, 1952) in his book “Overland Expedition from Morton Bay to Port Essington”. “Swarms of whistling ducks occupied large ponds in the creek, but our shot was all used, and the small iron-pebbles which we used as a substitute were not heavy enough to kill even a duck.” Such are the beginnings of science. The discovery of marine manganese nodules begins with the voyage of the H.M.S. Challenger, 1872-1876. Deep-sea nodules were recovered for the first time on 18 February 1873 approximately 300 km southwest of the island of Ferro in the Canary Group (Murray and Renard, 1891). The results of this cruise were unique in as much as they were to dominate thinking on manganese nodules for over 80 years. Large quantities of nodules displaying a wide range of morphologies and internal structure; were recovered from the Atlantic, Indian and Pacific oceans (Fig. 1-1)T. he nodules were shown to consist of concentric bands of ferromanganese oxides around such diverse nuclei as pumice, coral, phosphorite nodules, volcanic ash, palagonite, sharks’ teeth and glacial erratics. A slow growth rate for the nodules was established and some of the nodules were shown to have broken in situ and subsequently accreted manganese around the broken surfaces. Great diversity in appearance in the nodules was noted but generally nodules from a single site were similar in appearance and differed in size, form and internal appearance from those at another station; “so much so that now, after a detailed study of the collections, it is usually possible for us to state at sight from which Challenger station any particular nodule had been produced”. In many cases, the external form of the nodule depended on the shape of the nucleus and was often complicated by the incorporation of multiple nuclei into the nodule. The complexity of formation of the nodules is well illustrated by reference to samples from Station 281 (22” 21’s 150” 17’W, 4,360 m) in the South Pacific. Here, an ash shower fall appears to have covered nodules growing in red clay. The resultant slabs have subsequently been covered on the upper surface by further manganese oxides to give a complex depositional history (Fig. 1-2). <...>