274 



UNITED STATES MINERAL RESOURCES 



mined at gold mines throughout the world (0.3-0.5 

 oz per ton, or 10-17 ppm). Is any appreciable per- 

 centage of the total gold in the accessible parts of 

 the earth's crust present in concentrations inter- 

 mediate between those of porphyry copper ore and 

 currently minable gold ore, say 1-5 ppm, or is there 

 a real gap in the concentration range between these 

 two grades of ore, rather than only an apparent one 

 created by mining economics? A corollary question 

 concerns the distribution of gold near deposits of 

 gold and other metals: is gold confined largely to 

 the deposits themselves or does it decrease gradually 

 away from the deposits ; that is, does a gold-enriched 

 halo or "assay wall" commonly bound a gold-bearing 

 deposit ? 



Other gaps in knowledge include the mode of oc- 

 currence of gold in minerals, especially those of 

 mafic rocks, and the distribution of gold in porphyry 

 copper deposits and their wallrocks. 



A final problem, for the most part not a geologic 

 one, concerns the lack of up-to-date information on 

 the gold resources of the U.S.S.R. Although Russia 

 has the second largest gold production in the world 

 and is believed to have substantial reserves and re- 

 sources, almost nothing has been published on its 

 production, reserves, resources, or economics since 

 the midthirties. If, as some analysts believe, indus- 

 trial demand for gold has already reached the cur- 

 rent level of production, or will do so in the near 

 future, then Russian output may play an important 

 role in determining both the price of gold and its 

 degree of utilization. 



REFERENCES CITED 



Ageton, R. W., 1970, Gold, in Mineral facts and problems: 

 U.S. Bur. Mines Bull. 650, p. 573-585. 



Antweiler, J. C, and Love, J. D., 1967, Gold-bearing sedi- 

 mentary rocks in northwest Wyoming — a preliminary re- 

 port: U.S. Geol. Survey Circ. 541, 12 p. 



Bateman, A. M., 1950, Economic mineral deposits [2d ed.] : 

 New York, John Wiley & Sons, Inc., 916 p. 



Bateman, J. D., 1958, Uranium-bearing auriferous reefs at 

 Jacobina, Brazil: Econ. Geology, v. 53, p. 417—425. 



Busschau, W. J., 1967, Future trends in world gold produc- 

 tion: Mining Survey, no. 61, Sept. 1967, p. 17-21. 



Butler, B. S., Loughlin, G. F., Heikes, V. C, and others, 

 1920, The ore deposits of Utah: U.S. Geol. Survey Prof. 

 Paper 111, 672 p. 



Canada Geological Survey, 1970, Geology and economic min- 

 erals of Canada [5th ed.], R. J. W. Douglas, ed. : Econ. 

 Geology Rept. 1, v. 1, 838 p.; v. 2. 



Canadian Institute of Mining and Metallurgy, 1948, Struc- 

 tural geology of Canadian ore deposits: Montreal, Mer- 

 cury Press, Ltd., 948 p. 



Chamber of Mines of South Africa, 1969, 80th annual re- 

 port, 1969: Johannesburg, South Africa, 64 p. 



Commonwealth Mining and Metallurgical Congress, 6th, 



Canada, 1957, Structural geology of Canadian ore de- 

 posits, 524 p. 



Commonwealth Mining and Metallurgical Congress, 8th, 

 Australia and New Zealand, 1965, Geology of Australian 

 ore deposits, v. 1 [2d ed.] : Melbourne, 547 p. 



Connolly, J. P., and O'Harra, C. C, 1929, The mineral wealth 

 of the Black Hills: South Dakota School Mines Bull. 

 16, 418 p. 



Cooke, H. C, 1946, Canadian lode gold areas (Summary ac- 

 count) : Canada Dept. Mines and Resources, Econ. 

 Geology Ser. no. 15, 86 p. 



DeKun, Nicolas, 1965, The mineral resources of Africa: 

 Amsterdam, Elsevier Pub. Co., 740 p. 



Emmons, W. H., 1937, Gold deposits of the world: New York, 

 McGraw-Hill Book Co., 562 p. 



Erickson, R. L., Marranzino, A. P., Oda, Uteana, and Janes, 

 W. W., 1964, Geochemical exploration near the Getchell 

 mine, Humboldt County, Nevada: U.S. Geol. Survey 

 Bull. 1198- A, 26 p. 



Gold Producers Committee, 1967 (?), The outlook for gold 

 mining — the role of the gold mining industry in the 

 future economy of South Africa: Gold Producer's Com- 

 mittee, Chamber of Mines, Transvaal and Orange Free 

 State, 63 p. 



Gottfried, David, Rowe, J. J., Tilling, R. L., 1972, Dis- 

 tribution of gold in igneous rocks: U.S. Geol. Survey 

 Prof. Paper 727, 42 p. 



Green, Timothy, 1968, The world of gold : New York, Walker 

 and Co., 242 p. 



Gross, W. H., 1968, Evidence for a modified placer origin for 

 auriferous conglomerates, Canavieiras mine, Jacobina, 

 Brazil: Econ. Geology, v. 63, p. 271-276. 



Hardie, B. S., 1966, Carlin gold mine, Lynn district, Nevada: 

 Nevada Bur. Mines Rept. 13, pt. A, p. 73-83. 



Hoyt, C. D., 1971, Gold, in U.S. Bur. Mines Minerals Year- 

 book 1969, V. 1-2, p. 521-538. 



International Geological Congress, 1930, The gold resources 

 of the world : Intemat. Geol. Cong., 15th, Pretoria, 1929, 

 457 p. 



Irving, J. D., 1904, Economic resources of the Black Hills, 

 with contributions by S. F. Emmons and T. A. Jaggar, 

 Jr.: U.S. Geol. Survey Prof. Paper 26, 222 p. 



Jones, R. S., 1968, Gold in meteorites and in the earth's 

 crust: U.S. Geol. Survey Circ. 603, 4 p. 



1969, Gold in igneous, sedimentary, and metamorphic 



rocks: U.S. Geol. Survey Circ. 610, 28 p. 



1970, Gold content of water, plants, and animals: 



U.S. Geol. Survey Circ. 625, 15 p. 



Jones, R. S., and Fleischer, Michael, 1969, Gold in minerals 

 and the composition of native gold: U.S. Geol. Survey 

 Circ. 612, 17 p. 



Kavanagh, P. M., 1968, Have 6,000 years of gold mining ex- 

 hausted the World's gold reserves?: Canadian Mining 

 and Metall. Bull., v. 61, no. 672, p. 553-558. 



Koschmann, A. H., and Bergendahl, M. H., 1968, Principal 

 gold-producing districts of the United States: U.S. 

 Geol. Survey Prof. Paper 610, 283 p. 



Krauskopf, K. B., 1967, Introduction to geochemistry: New 

 York, McGraw-Hill Book Co., 721 p. 



Lee, Tan, and Yao, Chi-Lung, 1970, Abundance of chemical 

 elements in the earth's crust and its major tectonic units: 

 Internat. Geology Rev., v. 12, no. 7, p. 778-786. 



Lindgren, Waldemar, 1933, Mineral deposits [4th ed.] : New 

 York, McGraw-Hill Book Co., 930 p. 



