UNITED STATES MINERAL RESOURCES 



COPPER 



By Dennis P. Cox, Robert G. Schmidt, James D. Vine, Harold Kirkemo, 

 Elizabeth B. Tourtelot, and Michael Fleischer 



CONTENTS 



Page 



Abstract of conclusions 163 



Properties, uses, and resources 164 



Exploitation 165 



Geologic environment 166 



Geochemistry and abundance 166 



Geochemical cycle 167 



Mineralogy 168 



Types of deposits 169 



Porphyry copper deposits and related types- 169 



Porphyry copper deposits 169 



Veins, pipes, and replacement deposits 171 



Strata-bound deposits in sedimentary rocks- 172 



The Kupferschiefer 173 



The African copper belt 173 



Precambrian sedimentary copper de- 

 posits in the United States 174 



Precambrian sedimentary copper de- 

 posits in the U.S.S.R. I75 



Red-bed copper deposits I75 



Modern sea floor nodules 17G 



Metal-rich sediments of the Red Sea 170 



Horizontal transport of secondary 



copper deposits 176 



Mobilized deposits of probably sedi- 

 mentary origin 177 



Environments of deposition 177 



Size and grade characteristics 178 



Massive sulfide deposits in volcanic rocks — 178 



Copper in nickel ores 179 



Native copper deposits of the Keweenaw type 179 



Miscellaneous types 180 



Resources 180 



Identified and hypothetical resources 180 



Speculative resources 181 



Subeconomic resources 183 



Prospecting techniques 185 



Problems for research 186 



Selected references 186 



FIGURES 



20. Graph showing U.S. supplies and uses of cop- 

 per, 1960-71 



Page 



165 



22. 



Graph showing U.S. primary copper produc- 

 tion, 1850-1970 



Graph showing size and grade characteristics 

 of selected copper ore bodies 



TABLES 



37. 

 38. 



39. 

 40. 

 41. 



abstract of conclusions 



166 



171 



Copper supply and demand data, 1950-71, and 



projections for the year 2000 165 



Copper content of various materials 167 



Minerals of copper; composition and environ- 

 ment of origin 168 



Identified and hypothetical copper resources _- 180 

 Summary of speculative resources of copper. _ 183 

 Partial list of subeconomic (conditional) re- 

 sources of copper 184 



About 70 percent of the world's identified copper resources 

 can be grouped in the following geologic-geographic cate- 

 gories, listed in order of decreasing importance: porphyry 

 copper deposits of Chile and Peru, porphyry copper deposits 

 of the Southwestern United States (19 percent of the world 

 total), sedimentary copper deposits of Zaire and Zambia, 

 and porphyry copper and sedimentary copper deposits of 

 the U.S.S.R. Other important groups of identified resources 

 include porphyry copper deposits in Oceania, in Mexico, and 

 in western Canada and porphyry copper and sedimentary 

 copper deposits in southeastern and central Europe, respec- 

 tively. These and the remaining identified resources amount 

 to 344 million tons of copper metal, sufficient to last for 50 

 years at present rates of mine production. 



Hypothetical resources, or those not now known but 

 suspected to be present near known deposits, will probably 

 provide another 400 million tons of copper. Important re- 

 resources of this category are most likely to occur in the 

 porphyry copper provinces of southeastern Arizona, western 

 Canada, Chile, and Peru. Large sedimentary deposits will 

 probably be found in Africa, the U.S.S.R., and the northern 

 Rocky Mountains of the United States. Additional resources 

 in sea-floor manganese nodules also will probably be dis- 

 covered. 



U.S. GEOL. SURVEY PROF. PAPER 820 



163 



