74 • Marine Minerals: Exploring Our New Ocean Frontier 



Table 2-7.— Resource Potential of Cobalt, Nickel, 



Manganese, and Platinum in Crusts of U.S. Trust 



and Affiliated Territories 



Resource potential 



Nickel Platinum 



Territory Cobalt (txlO°) Manganese (ozxlO°) 



Belau/Palau 0.55 0.31 15.5 0.68 



Guam 0.55 0.31 15.5 0.68 



Howland-Baker 0.19 0.11 5.5 0.48 



Jarvis 0.06 0.03 1.6 0.15 



Johnston Island 1.38 0.69 41.6 3.50 



Kingman— Palmyra . 3.38 1.52 76.1 5.70 



Marshall Islands 10.55 5.49 281.3 21.50 



Micronesia 17.76 9.96 496.0 34.70 



Northern Mariana 



Islands 3.60 1.97 100.2 7.70 



Samoa 0.03 0.01 0.8 0.04 



Wake 0.98 0.51 26.8 2.00 



NOTE: The above are estimates of in-place resources and as such do not indicate 



either potential recoverability or mineable quantities. 

 SOURCE: Allen L. Clarl(, Peter Humphrey, Charles J. Johnson, and Dorothy K. 



Pak, Cobalt-Rich Manganese Crust Potential, OCS Study MMS 85-0006, 



1985, p. 20. 



trations would be most common in areas of low 

 sediment cover that have been within the geographi- 

 cally favorable equatorial zone for the majority of 

 their geologic history. 



The East-West Center's procedure was to use 

 detailed bathymetric maps to determine permissive 

 areas for each EEZ of the U.S. Trust and Affiliated 

 Territories in the Pacific. The permissive areas in- 

 cluded all the seafloor between the depths of 2,600 

 and 7,900 feet, making corrections for areas of sig- 

 nificant slopes. Then, based on published data, the 

 metal content and thickness of crust occurrences 

 for each area were averaged. Crust thicknesses were 

 also assigned on the basis of ages of the seamounts, 

 guyots, and island areas. Seamounts older than 40 

 million years were assigned a thickness of 1 inch. 

 Seamounts younger than 10 million years were as- 

 signed a thickness of one-half inch, and seamounts 

 younger than 2 to 5 million years were not included 

 in the resource calculations. These data are sum- 

 marized in table 2-7. 



According to table 2-7, the five territories of high- 

 est resource potential would be the Federated States 

 of Micronesia, Marshall Islands, Commonwealth 

 of the Northern Mariana Islands, Kingman- 

 Palmyra Islands, and Johnston Island. Further ge- 

 ologic inference suggests that the resource poten- 

 tial of the Federated States of Micronesia and the 

 Commonwealth of the Northern Mariana Islands 



could be reduced because of uncertainties in age 

 and degree of sediment cover. Thus, according to 

 their more qualitative assessment, the largest re- 

 source potential for cobalt crusts would likely be 

 in the Marshall Islands, followed by the Kingman- 

 Palmyra, Johnston, and Wake Islands (figure 2- 

 13). The territories of lesser resource potential 

 would include, in decreasing order, the Federated 

 States of Micronesia, Commonwealth of the North- 

 ern Mariana Islands (figure 2-14), Belau-Palau, 

 Guam, Howland-Baker, Jarvis, and Samoa. ^^ 



Another assessment of crust resource potential 

 using grade and permissive area cedculations with 

 geologic and oceanographic criteria factored in is 

 given in table 2-8.^° This assessment is also a qual- 

 itative ranking without attempting to quantify ton- 

 nages. In this regard, other factors that would have 

 to be considered to assess the economic potential 

 of any particular area include: nearness to port fa- 

 cilities and processing plants, and the cost of trans- 

 portation. In addition, factors highly critical to the 

 economics of a potential crust mining operation 

 would be the degree to which the crust can be sep- 

 arated from its substrate and the percentage of the 



"Ibid., p. 21. 



^'J.R. Hein, L.A. Morgenson, D.A. Glague, and R.A. Koski, 

 "Cobalt-Rich Ferromanganese Crusts From the Exclusive Economic 

 Zone of the United States and Nodules From the Oceanic Pacific," 

 D. Scholl, A. Grantz, and J. Vedder (eds.). Geology and Resource 

 Potential of the Continental Margins of Western North America and 

 Adjacent Ocean Basins, American Association of Petroleum Geolo- 

 gists, Memoir (in press), 1986. 



Table 2-8.— Estimated Resource Potential of Crusts 



Wittiin the EEZ of Hawaii and U.S. Trust 



and Affiliated Territories 



Relative 

 Pacific area banking Potential 



Marshall Islands 1 High 



Micronesia 2 High 



Johnston Island 3 High 



Kingman-Palmyra 4 High 



Hawaii-Midway 5 Medium 



Wake 6 Medium 



Howland-Baker 7 Medium 



Northern Mariana Islands 8 Low 



Jarvis 9 Low 



Samoa 10 Low 



Belau/Palau 11 Low 



Guam 12 Low 



SOURCE: Modified from J.R. Hein, F.T. Manheim, and W.C. Schwab, Cobalt-Rlctj 

 Ferromanganese Crusts From the Central Pacific, OTC 5234, Offshore 

 Technology Conference, May 1986, pp. 119-126. 



