Subsea Mineral Resources U.S. GEOLOGICAL SURVEY BULLETIN 1689-A Chapter A Subsea Mineral Resources By V. E. McKELVEY US. GEOLOGICAL SURVEY BULLETIN 1689 MINERAL AND PETROLEUM RESOURCES OF THE OCEAN DEPARTMENT OF THE INTERIOR DONALD PAUL MODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director UNITED STATES GOVERNMENT PRINTING OFFICE: 1986 For sale by the Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 Library of Congress Cataloging-in-Publication Data McKelvey, V. E. (Vincent Ellis), 1916- Subsea mineral resources. (U.S. Geological Survey bulletin ; 1689-A) Bibliography: p. 95 Supt. of Docs, no.: I 19.3:1689-A 1. Marine mineral resources. I. Title. II. Series. QE75.B9 no. 1689-A 557.3s 86-600199 [TN264] [553'.09162] CONTENTS Abstract 1 Introduction 2 Concepts of reserves and resources 3 Definitions 4 Classification 4 Summary 7 Geology of the continental margins and ocean basins 7 Continental margins 7 Deep-ocean basins 8 Plate tectonic processes in the origin of subsea geologic provinces 9 Subsea minerals in relation to the continent-ocean framework 9 Marine placers 9 Placer minerals 10 Geologic environments favorable for the formation of placers 10 Placers in the marine environment 11 World distribution of marine placer deposits 12 Guides to prospecting for offshore placers 13 Offshore sand, gravel, and calcium carbonate deposits 13 Sand and gravel 17 Shell 18 Other offshore sources of calcium carbonate 19 Precious coral 20 Phosphorite and guano 21 Mineralogy and goechemistry 22 Origin 22 Distribution 24 Guides to prospecting 27 Subsurface hard-mineral deposits of the continental margins 27 Metallic minerals 27 Coal 28 Other nonmetallic minerals 28 Manganese nodules and encrustations 29 Chemical composition 30 World and ocean averages 30 Relation to latitude 34 Relation to water depth 35 Metal-rich types of nodules 41 Mineralogy 55 Origin 56 Relation to water depth 57 Effects of direct precipitation from seawater in comparison with those from diagenetic precipitation 57 Relation to regional variation in sediment type, biologic productivity, and physiography 59 Distribution 61 The Clarion-Clipperton zone 62 Other areas containing nickel- and copper-rich nodules 67 Subsea Mineral Resources III Cobalt-rich encrustations 68 Manganese- and iron-rich encrustations 71 Feasibility of commercial recovery 72 Ferruginous and manganiferous sediments 73 Metallic sulfide deposits 78 Red Sea metalliferous sediments 78 Sulfide deposits on the mid-ocean ridges of the east Pacific 80 Sulfide deposits associated with volcanic seamounts 83 Analogs on land 83 Feasibility of commercial recovery 85 Jurisdiction over exploration and production 86 Red clays 86 Radiolarian ooze 88 Barite 88 Seawater 89 Energy in the oceans 89 The Law of the Sea 91 Ocean regimes established by the Convention 92 Provisions affecting mineral resources 92 Consequences for the United States 94 Acknowledgments 95 References cited 95 FIGURES 1. Tectonic map showing active oceanic ridge systems of the deep-ocean floor with which hydrothermal systems are likely to be associated and where sulfide min­ erals may have been deposited 3 2, 3. Diagrams showing: 2. Classification of mineral resources 5 3. Resource classification recommended by the UN group of experts 6 4. Idealized profile of a continental margin 8 5. Map showing world distribution of coastal placer deposits 12 6-8. Maps showing heavy-mineral distribution on the: 6. Washington-northern Oregon shelf 14 7. Central Oregon shelf 15 8. Southern Oregon-northern California shelf 16 9-12. Maps showing: 9. Distribution of gravel off the Northeastern United States 18 10. Gravel on the sea bottom off northern New Jersey 19 11. Sea-floor materials offshore Washington and northern Oregon 20 12. World distribution of precious coral 21 13. Diagram showing surface currents in an idealized ocean 23 14-16. Maps showing: 14. Distribution of subsea phosphorites 25 15. Distribution of phosphate deposits in the Southeastern United States 26 16. Manganese nodule stations in the Scripps Institution of Oceanogra­ phy's Sediment Data Bank as of March 1980 31 17-20. Plots showing relations between: 17. Manganese content in manganese nodules and their latitudes 36 18. Combined nickel and copper content in manganese nodules and their latitudes 37 IV Mineral and Petroleum Resources of the Ocean 19. Depth and combined nickel and copper content in manganese nodules 40 20. Depth and cobalt content in manganese nodules 41 21-23. Plots showing relations between depth and combined nickel and copper con­ tent in: 21. Pacific Ocean manganese nodules 42 22. Atlantic Ocean manganese nodules 43 23. Indian Ocean manganese nodules 44 24-26. Plots showing relations between depth and cobalt content in: 24. Pacific Ocean manganese nodules 45 25. Atlantic Ocean manganese nodules 47 26. Indian Ocean manganese nodules 48 27. Plot showing relation between depth and manganese content in manganese nodules 49 28-32. Maps showing distributions of: 28. Manganese nodules containing 1.8 percent Ni+Cu or more 50 29. Manganese nodules containing ^1.0 and <1.8 percent Ni+Cu 51 30. Manganese nodules containing 1.0 percent Co or more 52 31. Manganese nodules containing ^0.5 and <1.0 percent Co 54 32. Manganese nodules containing 35.0 percent Mn or more 55 33. Ternary plot of the principal mineral phases of manganese nodules at 107 stations for which all constituents have been analyzed 58 34. Map showing distribution of manganese nodules in the world ocean 62 35. Plot showing relation between depth and concentrations of manganese nod­ ules 63 36. Map showing areas in the northeastern equatorial Pacific Ocean in which man­ ganese nodules contain more than 1.8 percent Ni+Cu 64 37-39. Maps showing distributions of: 37. Manganese nodules having high metal contents in the Pacific Ocean 68 38. Manganese nodules having high metal contents in the South Atlantic Ocean 69 39. Manganese nodules having high metal contents in the Indian Ocean 70 40-42. Maps showing target areas for exploration for: 40. Manganese nodules rich in combined nickel and copper in the cen­ tral north equatorial Pacific Ocean 71 41. Manganese nodules rich in combined nickel and copper in the southeastern equatorial Pacific Ocean 72 42. Manganese nodules rich in combined nickel and copper in the cen­ tral south equatorial Indian Ocean 73 43. Plot showing distribution of dissolved manganese and iron in the Black Sea 76 44. Schematic cross section of the Nikopol bedded manganese deposits in the Soviet Union 77 45, 46. Maps showing: 45. Hot brine deeps in the Red Sea 79 46. Mid-ocean ridge sites where active hydrothermal circulation and as­ sociated massive sulfide deposits have been observed 80 47. Geologic sketch map of the southern Juan de Fuca rift valley 81 48. Map showing regions of the ocean expected to provide areas geologically suitable for subseabed waste disposal 87 TABLES 1. Areas of subsea physiographic provinces 8 Subsea Mineral Resources V 2. Placer minerals 11 3. Composition of phosphorites from various submarine localities 26 4. World metal contents, nodule concentrations, and depths of manganese nodules 32 5. Comparison of the world average metal contents of manganese nodules listed in table 4 with the values reported by Cronan (1980) 32 6. Principal metal contents, nodule concentrations, and depths of manganese nod­ ules in the Pacific, Atlantic, and Indian Oceans 32 7. Average principal metal contents of manganese nodules, by ocean 33 8. Other elements in manganese nodules of the world and of the Pacific, At­ lantic, and Indian Oceans 33 9, 10. Principal metal contents, nodule concentrations, depths, and metal ratios of manganese nodules, grouped by latitude, in: 9. The northern hemisphere 35 10. The southern hemisphere 35 11-13. Average and maximum principal metal contents of manganese nodules, cate­ gorized by latitude, in: 11. The Pacific Ocean 36 12. The Atlantic Ocean 37 13. The Indian Ocean 38 14. Means of other elements in manganese nodules of the world, grouped by latitude 39 15. Metal contents, nodule concentrations, and depths of metal ratios in manganese nodules in water depths of less than 2,000 and more than 4,000 m 40 16. Principal metal contents of manganese nodules in water depths above and below 3,000 m 43 17. Means of other elements in manganese nodules in water depths above and below 3,000 m 46 18-20. Metal contents, nodule concentrations, and depths of manganese nodules con­ taining: 18. 1.0 percent Ni+Cu or more 48 19. 1.0 percent Ni+Cu or more outside the Clarion-Clipperton zone 49 20. More than 0.5 percent Co and more than 35 percent Mn 50 21. Other elements in manganese nodules of the world, grouped by combined nickel and copper, manganese, and cobalt contents 53 22. World means and ocean maximums of several other elements in manganese nodules that have exceptionally high concentrations 56 23. Metal contents, nodule concentrations, and metal ratios of manganese nodules in the C-C' area at stations where information on both is available 65 24. Metal contents and metal ratios of manganese nodules in the C-C' area 65 25. Metal contents, nodule concentrations, and metal ratios of manganese nodules in the C-C' area at stations where the nodule concentration is 5 kg/m2 or more 66 26. Partial composition of metalliferous sediments (excluding sulfide facies) of the Red Sea 74 27. Ferruginous and manganiferous sediments at or near oceanic spreading centers 75 28. Chemical analyses of the sulfide facies of Red Sea sediments 80 29. Estimates of typical grades and values per ton of contained metals for sea- floor massive sulfide deposits, compared with typical ore from ophiolite mas­ sive sulfide deposits and deep-sea manganese nodules 82 30.