ZINC 



709 



PROBLEMS FOR RESEARCH 



Although a high potential for zinc resources in 

 all categories seems apparent, research is needed 

 on zinc and zinc-bearing deposits in all fields of the 

 geosciences to improve search techniques. More 

 imaginative thinking is necessary in the search for 

 conventional types of deposits to develop new con- 

 cepts that can improve our understanding of geo- 

 logic features localizing ore bodies and districts and 

 also the sources of the mineralizing fluids. Most 

 conventional deposits are considered to form during 

 a single period of mineralization and then to re- 

 main isolated from later geologic processes until 

 discovery. It is not logical to believe that deposits 

 formed hundreds of millions of years ago have 

 remained unchanged by the various geologic en- 

 vironments through which they have passed. Many 

 ore deposits may be more ephemeral than their host 

 rocks and in some environments could have been 

 completely or partially resorbed by new migrating 

 brines. The metals were precipitated from these new 

 brines to form new ores or were dispersed into sur- 

 face waters eventually to reach the sea. Search for 

 evidence of such removal, particularly if only in part, 

 and the tracing of the path of the brine migration, 

 might well lead to the discovery of the later and 

 possibly more enriched ores. Such solution and re- 

 deposition concepts may be particularly fruitful in 

 exploration for Mississippi Valley-type ores. Fur- 

 thermore, the metal-bearing brines, regardless of 

 their source, may have moved laterally many miles 

 through ancient carbonate aquifers to be trapped 

 in large reservoirs where different geochemical con- 

 ditions precipitated the metal. 



Further studies of geophysical techniques are 

 needed in the search for zinc-bearing ores. The 

 application of magnetic and electromagnetic tech- 

 niques are reasonably well understood. On the other 

 hand, gravity and seismic techniques have not been 

 pursued to any great extent. This may be largely 

 because they have been tried with no immediate 

 success or because they have been considered and 

 discarded on theoretical grounds, with no extensive 

 experimental studies. Gravity surveys may be par- 

 ticularly useful in locating large breccia bodies of 

 the Mississippi Valley type when concealed under a 

 relatively shallow cover. Another application of 

 gravity studies could be in the search for extensions 

 of high-grade zinc laterites under cover of dense 

 tropical vegetation. 



A better understanding of zinc geochemistry and 

 the geochemistry of potential environments of depo- 

 sition is of prime importance. The amphoteric na- 



ture of zinc and its role in the formation of oxidized 

 zinc deposits need further consideration. The anoma- 

 lous amounts of zinc in certain evaporitic rocks need 

 explanation to determine if further enrichment in 

 evaporites is possible — also whether such enrich- 

 ment, if stripped from its host, might be a source of 

 metal in ore fluids. Further investigation of zinc 

 geochemistry as applied to exploration investigations 

 will also be valuable. Simplification of field analytical 

 methods would be helpful for exploration geochemi- 

 cal surveys in remote areas. 



SELECTED REFERENCES 



Anderson, C. A., 1969, Massive sulfide deposits and volcanism : 

 Econ. Geology, v. 64, no. 2, p. 129-146. 



Anderson, C. A., and Creasey, S. C, 1958, Geology and ore 

 deposits of the Jerome area, Yavapai County, Arizona: 

 U.S. Geol. Survey Prof. Paper 308, 185 p. 



Barnes, M. P., and Simos, J. G., 1968, Ore deposits of the 

 Park City district [Utah], with a contribution on the 

 Mayflower lode, in Ridge, J. D., ed.. Ore deposits of the 

 United States 1933-1967 — The Graton-Sales volume, v. 

 2: New York, Am. Inst. Mining, Metall., and Petroleum 

 Engineers, p. 1102-1126. 



Bachau, Christian, 1971, Essai de typologie quantitative des 

 gisements de plomb et de zinc avec la repartition de 

 I'argent: Bur. Recherches Geol. et Minieres Bull., 2d 

 ser., sec. 2, no. 3, p. 1-72; no. 4, p. 1-47. 



Bischoff, J. L., and Manheim, P. T., 1969, Economic poten- 

 tial of the Red Sea heavy metal deposits, in Degens, 

 E. T., and Ross, D. A., eds.. Hot brines and recent heavy 

 metal deposits in the Red Sea: New York, Springer- 

 Verlag, p. 535-549. 



Bishop, 0. M., 1960, Zinc, in Mineral facts and problems: 

 U.S. Bur. Mines Bull. 585, p. 975-994. 



Boyle, R. W., 1961, Native zinc at Keno Hill [Yukon] : Cana-. 

 dian Mineralogist, v. 6, pt. 5, p. 692-694. 



Borckie, D. C, Hare, E. H., Jr., and Dingess, P. R., 1968, 

 The geology and ore deposits of the Tri-State district 

 of Missouri, Kansas, and Oklahoma, in Ridge, J. D., ed.. 

 Ore deposits of the United States — The Graton-Sales 

 volume, V. 1 : New York, Am. Inst. Mining, Metall., and 

 Petroleum Engineers, p. 400-430. 



Brown, J. S., ed., 1967, Genesis of stratiform lead-zinc- 

 barite-fluorite deposits (Mississippi Valley-type de- 

 posits) — A symposium. New York, 1966: Econ. Geology 

 Mon. 3, 3,433 p. 



Bush, J. B., Cook, D. R., Lovering, T. S., and Morris, H. T., 

 1960, The Chief Oxide-Burgin area discoveries. East 

 Tintic district, Utah — a case history: Econ. Geology, v. 

 55, no. 7, p. 1116-1147, 1507-1540. 



Campbell, Neil, 1967, Tectonics, reefs, and stratiform lead- 

 zinc deposits of the Pine Point area, Canada, in Brown, 

 J. S., ed.. Genesis of stratiform lead-zinc-barite-fluorite 

 deposits (Mississippi Valley-type deposits) — A sympo- 

 sium, New York, 1966: Econ. Geology Mon. 3, p. 59-70. 



Carvalho, P., Guimaraes, Djalma, and Dequech, David, 1962, 

 Jazida plumbo-zincifera do Municipio de Vazante, Minas 

 Gerais [Brazil]: Brasil, Dept. Nac. Produgao Mineral, 

 Div. de Fomento, Bull. 110, 119 p. 



Dana, E. S., 1945, A textbook of mineralogy, 4th ed. (re- 



