370 



UNITED STATES MINERAL RESOURCES 



dian Shield, largely covered by glacial drift, it seems 

 unlikely that more than a modest fraction of the 

 existing lithium pegmatites have been found. 



SOUTH AMERICA 



Pegmatites in northeastern Brazil have been 

 mined for both spodumene and amblygonite. The 

 production, though small, is enough to encourage 

 hope that more can be found. 



Argentina is the only other South American 

 country that has been a source of lithium, but 

 whether its pegmatites have a significant potential 

 is questionable. 



Lithium pegmatites have been found in so many 

 parts of Africa that only the outstanding localities 

 can be mentioned here. The Bikita pegmatite in 

 Rhodesia is preeminent. Cooper (1964) and Martin 

 (1964) described this as a well-zoned pegmatite, 

 5,400 feet long, that contains abundant lepidolite 

 and petalite and lesser quantities of spodumene, 

 amblygonite, and eucryptite. The only other locali- 

 ties with a notable record of production are the 

 Karibib and Warmbad districts, South West Africa, 

 which contain zoned pegmatites described by Cam- 

 eron (1955) that have been sources of lepidolite, 

 petalite, and amblygonite. The Manono tin deposits, 

 Republic of the Congo (Zaire) , have attracted inter- 

 est as potential sources of lithium. These deposits 

 are in two pegmatites, each said to be 3.5 miles long 

 and 150-2,500 feet wide and to contain 10-25 per- 

 cent spodumene (Kesler, 1960, p. 527). 



Lithium pegmatites are known in many parts of 

 Europe and Asia, but none of the deposits have a 

 record of large production nor is there published 

 evidence for large reserves. The chief localities are 

 in Czechoslovakia, France, East Germany, Portugal, 

 Spain, Sweden, Soviet Union, India, and Korea. The 

 best known of the western European deposits is the 

 Varutrask pegmatite in northern Sweden, which 

 contains lepidolite, petalite, spodumene, and am- 

 blygonite (Quensel, 1952, p. 53-55). France and 

 Portugal have each produced more than 4,000 tons 

 of lepidolite (Schreck, 1961, table 9). In the U.S.S.R., 

 deposits on Kola Peninsula and in the Altai Moun- 

 tains may be important, but available published data 

 are not adequate for evaluating them. 



AUSTRALIA 



Several pegmatite districts in Australia are known 

 to have lithium minerals, and the very small pro- 



duction may not be an accurate measure of the 

 potential. Western Australia contains most of the 

 known occurrences. Spodumene, amblygonite, lepi- 

 dolite, and petalite have all been reported (Noakes, 

 1946, p. 9-12). 



LITHIUM IN BRINES 



Lithium has been obtained since 1938 from sub- 

 surface brine at Searles Lake, Calif., and since 1966 

 from another dry lake at Silver Peak, Nev. The 

 Silver Peak deposit has become a very large sup- 

 plier of lithium, probably the world's largest, but 

 production figures are unpublished. 



At Searles Lake the lithium is from an operation 

 in which potassium chloride and sodium carbonate, 

 sulfate, and borate are the main products. The brine 

 contains about 0.015 percent LiaO (Ryan, 1951, 

 table 1), or 70 ppm lithium, which is extracted as 

 dilithium sodium phosphate that contains about 21 

 percent LizO. 



At Silver Peak, according to Barrett and O'Neill 

 (1970), the brine contains 300 ppm lithium and 

 10-15 percent other dissolved constituents, of which 

 chlorine and sodium are by far the most abundant. 

 Lithium is the sole product. The well field from 

 which the brine is obtained extends over an area of 

 about 2 square miles, but the entire playa covers 

 about 32 square miles. Clays, silts, sands, and 

 evaporites are saturated with brine to a depth of 

 at least 600 feet and possibly to 1,500 feet. I. A. 

 Kunasz, in a 1970 Pennsylvania University doctorate 

 thesis, "Geology and Geochemistry of the Lithium 

 Deposit in Clayton Valley, Esmeralda County, Ne- 

 vada," showed that the playa sediments have abun- 

 dant hectorite obtained by erosion from nearby tuff. 

 The hectorite was probably formed originally by 

 hydrothermal alteration along a fault. Lithium of 

 the brine, according to Kunasz, was leached from the 

 tuff, and additional lithium may have been con- 

 tributed by hot springs at the periphery of the 

 basin. 



The development of the Silver Peak locality has, 

 by putting substance into what previously was only 

 a promise, greatly increased interest in lithium of 

 brines. Earlier analyses of saline deposits either 

 indicated no more than teasing amounts of lithium, 

 which implied that nothing better than byproduct 

 lithium, as at Searles Lake, would ever be found, 

 or were themselves of dubious validity (Norton and 

 Schlegel, 1955, p. 340). An additional source of pro- 

 duction has now been developed at Great Salt Lake 

 (Indus. Minerals, Dec. 1971, p. 37), which contains 

 about 60 ppm lithium that is extracted together 

 with magnesium. The Salton Sea geothermal brine 



