. The Earth beneath the sea : History . Fig. 11. 42° 50'S, 125° 32'W. Depth 4560 m. Pacific Basin. Area of picture 2h by 2| m. ( Navy Electronics Laboratory photo by C. J. Shipek.) Large and small manganese nodulea or thickly encrusted rocks resting on a cal- careous ooze. Note complete absence of sediment cover. and more recently in the western Atlantic (Elmendorf and Heezen, 1957; Heezen, Tharp and Ewing, 1959) (Fig. 12), and in the Scotia Sea. In the Pacific they occur in sufficient quantities to constitute a potentially economic source for manganese, copper, cobalt and nickel. Som
. The Earth beneath the sea : History . Fig. 11. 42° 50'S, 125° 32'W. Depth 4560 m. Pacific Basin. Area of picture 2h by 2| m. ( Navy Electronics Laboratory photo by C. J. Shipek.) Large and small manganese nodulea or thickly encrusted rocks resting on a cal- careous ooze. Note complete absence of sediment cover. and more recently in the western Atlantic (Elmendorf and Heezen, 1957; Heezen, Tharp and Ewing, 1959) (Fig. 12), and in the Scotia Sea. In the Pacific they occur in sufficient quantities to constitute a potentially economic source for manganese, copper, cobalt and nickel. Sometimes they are extremely well rounded (in the Scotia Sea) and at other times they are moderately angular. They vary in size from microscopic up to half a metre or more in diameter and can be recognized in photographs from their uniform distribution over the bottom and from the fact that they are found in areas where clastic and erratic boulders are very rare. Nodules of phosphorite (Fig. 13) have been photo- graphed, dredged and described by Emery and Dietz (1950). In high latitudes, the proportion of erratic rocks caused by melting icebergs becomes appreciable and it is necessary to distinguish them from those locally derived. Although it may be possible to do this solely on the proportions of
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
