FLUORINE 



233 



associated with fluorine deposits. Friedrich and 

 Pliiger (1971) found that lead, zinc, and mercury 

 contents of soils were useful guides in exploring for 

 fluorite in Spain and that mercury was useful in the 

 Wolsendorf district, Germany. If fluorite contains 

 uranium minerals, as in the Thomas Range, Utah, 

 and Jamestown, Colo., scintillation counters or 

 Geiger counters might be helpful in prospecting for 

 fluorspar. 



Recent work in western North America has shown 

 that fluorite deposits can effectively be sought by 

 geochemical and heavy-mineral techniques. Fluorite 

 persists for long distances during transport in the 

 sediment of streams and can be concentrated there- 

 from with the gold pan. A systematic heavy-mineral 

 survey near Winston, N. Mex., during 1970, by H. V. 

 Alminas and K. C. Watts (oral commun., 1971), 

 showed that fluorite is plentiful in sediment near two 

 major subparallel north-trending faults, near the 

 intersection of which an independent operator re- 

 cently found a large fluorspar deposit. 



Geochemical exploration investigations in the 

 Browns Canyon district, Colorado, by Van Alstine 

 (1965) showed that fluorine is found in abnormal 

 concentrations in residual soil directly above and 

 downslope from the principal vein and in alluvium 

 downstream from the vein. The abundance of fluo- 

 rine in those places may be due in part to the semi- 

 arid climate of the area. Van Alstine also pointed out 

 that abundant biotite and hornblende increase fluo- 

 rine values over that attributed to fluorite because of 

 the fluorine content of the dark minerals. This prob- 

 lem is avoided by determining content of fluorite 

 instead of fluorine. 



Neither heavy-mineral nor geochemical prospect- 

 ing methods for fluorite and fluorine have been well 

 developed for fluorspar districts in humid regions. 

 Geochemical studies of stream sediment and soils 

 were found to be useful in prospecting for fluorine in 

 the Hwanggangri region, Korea (Sang Kyu Yun and 

 others, 1970). 



Geophysical techniques have been utilized to some 

 degree in evaluating mineralized areas that have 

 fluorine potential. Electrical methods have been suc- 

 cessful in outlining faults, some of which contain 

 fluorspar (Hubbert, 1944), and alteration zones as- 

 sociated with fluorspar veins (Johnson, 1971). The 

 refraction seismic method has been used as an in- 

 direct means of exploring for fluorspar in southern 

 Illinois (Johnson, 1957). In general, it seems im- 

 practicable or impossible to detect minable bodies 

 directly by methods of geophysical prospecting. The 

 value of geophysical techniques is in finding locally 

 mineralized faults, dikes, and altered zones, which 



then require geologic evaluation to determine fluo- 

 rine potential. 



PROBLEMS FOR RESEARCH 



The distribution of fluorine in nature is only part- 

 ly understood, and more research is needed on the 

 geology and geochemical cycle of fluorine, especially 

 on the partitioning of fluorine in geologic processes. 

 Our present knowledge is not advanced enough even 

 to adequately estimate crustal abundance, much less 

 to accurately estimate resources. The fluorine con- 

 tent of igneous rocks serves as an excellent guide to 

 potential fluorine deposits in the vicinity of such 

 rocks ; and yet, fluorine is commonly not determined 

 in igneous rock analyses. Fluorine determinations 

 should be made routinely in all chemical analyses of 

 igneous rocks. 



New techniques are needed to explore for and to 

 evaluate fluorine deposits. Geochemical investiga- 

 tions of the fluorine content of rocks, soils, plants, 

 and waters hold some promise as an exploration 

 technique. However, for geochemical exploration to 

 be useful, a quick, reliable, and inexpensive method 

 of testing for fluorine needs to be developed. 



Utilization of potential low-grade multicommodity 

 ores as fluorine resources will require refinement and 

 improvement of mining and processing techniques. 

 Many of these low-grade deposits are very fine 

 grained, and the fluorine minerals are intimately 

 intergrown with other minerals, such as chalcedonic 

 quartz, so that separation of the fluorine minerals is 

 diificult. 



REFERENCES CITED 



Abramovich, Yu. A., and Nechayev, Yu. A., 1960, Authigenic 

 fluorite in Kung-urian deposits of the Permian Preurals : 

 Doklady Akad. Nauk SSSR, v. 130, p. 1288-1289. 



Abreu, S. F., 1960, Recursos minerais de Brasil: Rio de 

 Janeiro, Inst. Nac. de Technologia, v. 1, 471 p. 



Bakr, M. A., 1965, Fluorspar deposits of Pakistan: Pakistan 

 Geol. Survey Rec, v. 16, pt. 2, 5 p. 



Barth, T. F. W., 1947, On the geochemical cycle of fluorine: 

 Jour. Geology, v. 55, no. 5, p. 420-426. 



Blake, H. E., Jr., Thomas, W. S., Moser, K. W., Reuss, J. L., 

 and Dolezal, H., 1971, Utilization of waste fluosilicic 

 acid: U.S. Bur. Mines Rept. Inv. 7502, 60 p. 



Chermette, A., 1960, Les resources de la France en spath 

 flour: Bur. Recherches Geol. et Minieres, no. 1, 56 p. 

 1968, Le marche du spath-fluor dans le monde: Ex- 



trait des Mines et Metallurgie, Paris, Mai a Decembre, 



14 p. 

 Davidson, C. F., 1966, Some genetic relationships between 



ore deposits and evaporites : Inst. Mining and Metallurgy 



Trans., sec. B, v. 75, Bull. 717, p. B216-B225. 

 Deans, T., 1966, Economic mineralogy of African carbona- 



tites, in Tuttle, 0. F., and Gittins, J., eds., Carbonatities : 



New York, Intersci. Publishers (John Wiley & Sons), 



p. 385-416. 



