(Table 1, Pages 189-191) Physical characteristics of manganese nodules collected in the Atlantic Ocean during cruise RC15 (R/V Robert D. Conrad) in the vicinity of the Nares Abyssal Plain

Intensive surveys were made in an abyssal hill province in the North Atlantic at the northeast edge of the Nares Abyssal Plain, where the general conditions favorable for the formation of manganese nodules prevail, i.e., deep water (2600-3300 fm) and low rate of sediment accumulation. Typically, manganese nodules were observed to be abundant in one spot, and just a short distance away, under conditions which seemed to be the same, the ocean floor was completely devoid of nodules. Efforts to develop effective surveying techniques were very successful, particularly use of Kennecott grabbers and a new PINGERPROBE technique in conjunction with satellite navigation.