Northern Chile

Mineral Deposits. The only iodine obtained from minerals has been a by-product of the processing of nitrate ores in Chile. CaUche occurs in the Atacama desert of Northern Chile and west of the Andes mountains. The Atacama desert is known as the driest of the world s deserts, where measurable (>1 mm) rainfalls may be as infrequent as once every 5—29 years (58). The caUche deposits occur in an area averaging 700 km (north—south) by 30 km (east—west). The iodine may total over 5 x 10 t (59). 

G. E. Ericksen, Geology of the Salt Deposits and the Salt Industry of the Northern Chile, U.N. Special Fund Chile Mineral Survey Project, Washington,... 

Sa.Ia.rs and Lakes. Brines having high lithium concentration are found in salars of northern Chile, southwestern Bohvia, and northwestern Argentina. Brines of lower lithium concentration are found in salars in the western United States and the Tibetan Plateau. Brines pumped from beneath the surface of the Salar de Atacama (Chile) and Silver Peak (Clayton Valley, Nevada) are used for commercial production of lithium uti1i2ing solar evaporation (see Chemicals frombrines). The concentration of selected ions in brines from salars and lakes of potential commercial interest worldwide are shown in Table 1. 

Numerous theories exist as to how the Chilean deposits formed and survived. It has been postulated that the unique nitrate-rich caUche deposits of northern Chile owe their existence to an environment favorable to accumulation and preservation of the deposits, rather than to any unusual source of the saline materials (2). The essential conditions are an extremely arid climate similar to that of the Atacama desert in the 1990s, slow accumulation during the late Tertiary and Quaternary periods, and a paucity of nitrate-utilizing plants and soil microorganisms. 

SQM Nitratos (Chile) operates two sodium nitrate plants in northern Chile Pedro de Valdivia and Mama Elena, about 30 km distant from one another. The caUche is mined in open-pit areas. A solar evaporation plant, Coya Sur, Hes in between. A flow sheet of the processing operations for sodium nitrate production is shown in Figure 2. 

Robst AL, Lowenstein TK, Jordan TE, Godfrey LV, Ku T-L, Luo S (2001) A 106 ka paleoclimate record from drill core of the Salar de Atacama, northern Chile. Paleogeo Paleoclim Paleoecol 173 21-42 Rosholt JN (1957) Quantitative radiochemical methods for determination of the sources of natural radioactivity. Anal Chem 29 1398-1408... 

South America has two major areas, separated by the Andes Mountain ridges, where arid and semi-arid zones dominate. In the barren, coastal Atacama desert of Peru and northern Chile, precipitation is extremely limited and comes as winter mists or drizzles. In the rain shadow east of the Andes in Argentina, arid zones are widespread. South America apparently has only a slightly greater proportion of dry zones than North America. 

Cartmell, L.W., Aufderheide, A.C., Springfield, A., Weems, C. and Arriaza, B. (1991). The frequency and antiquity of Prehistoric coca-leaf-chewing practices in Northern Chile radioimmunoassay of cocaine metabolite in human mummy hair. Latin American Antiquity 2 260-268. 

Lee CE (2002) Evolutionary genetics of invasive species. Trends Ecol Evol 17 386-391 Leonardi PI, Miravalles AB, Faugeron S, Flores V, Beltran J, Correa JA (2006) Diversity, phenomenology and epidemiology of epiphytism in farmed Gracilaria chilensis (Rhodophyta) in northern Chile. Eur J Phycol 41 247-257... 

Phase behavior 1n concentrated aqueous electrolyte systems is of interest for a variety of applications such as separation processes for complex salts, hydrometal 1urgical extraction of metals, interpretation of geological data and development of high energy density batteries. Our interest in developing simple thermodynamic correlations for concentrated salt systems was motivated by the need to interpret the complex solid-liquid equilibria which occur in the extraction of sodium nitrate from complex salt mixtures which occur in Northern Chile (Chilean saltpeter). However, we believe the thermodynamic approach can also be applied to other areas of technological interest. 

Constantino M. Torres, David B. Repke, Kelvin Chan, Dennis McKenna, Augustin Llagostera, and Richard E. Schultes. "Botanical, chemical, and contextual analysis of archaeological snuff powders from San Pedro de Atacama, Northern Chile." Current Anthropology 32 (1992) 640-49. 

Soda niter or sodium nitrate (NaNO ) is the most abundant of the nitrate minerals. It is used for fertilizer, explosives, and preservatives. The natural deposits are located in northern Chile, which was the original source for many years. More recently, nitrogen fixation, which extracts nitrogen from air, has been used for producing sodium nitrate. This synthetic process has greatly increased the availability of this useful sodium salt by ehminating the need for the natural source. It is used to preserve and cure meats and is used in photography, in pharmaceuticals, and as a color fixative in fabrics. 

Surface geochemical anomalies in northern Chile product of the extended metallogenesis of buried copper deposits... 

Fig. 1. Distribution of copper deposits in northern Chile including those containing atacamite in the oxide zone. DFZ is the Domeyko Fault Zone and ACL is Antofagasta-Calama Lineament. The land between the High Andes and the coast is the hyper-arid central Atacama Desert.

Fig. 2. Geochronology of supergene processes for copper deposits in northern Chile (modified from Reich et al. 2009).

Arancibia, G., Matthews, S.J., Perez De Arce, C. 2006. K-Ar and °Ar Ar geochronology of supergene processes in the Atacama Desert, Northern Chile tectonic and climatic relations. Journal Geological Society London, 163, 107-118. 

Cameron, E.M., Leybourne, M.I., Palacios, C. 2007. Atacamite in the oxide zone of copper deposits in northern Chile Involvement of deep formation waters Mineralium Deposita, 42, 205-218. 

Palacios, C., Guerra, N., Townley, B., Lahsen, A. Parada, M. 2005. Copper geochemistry in salt from evaporate soils, Coastal Range of the Atacama Desert, northern Chile an exploration tool for blind Cu deposits. Geochemistry Exploration, Environment, Analysis, 5, 371-378. 

Sillitoe, R.H. Burrows. D.R. 2002. New field evidence bearing on the origin of the EL Laco magnetite deposit, northern Chile. Economic Geology, 97, 1101-1109. 

Petrographic characterization of propylitic alteration associated with porphyry Cu-Mo deposits in the Collahuasi District, Northern Chile implications for mineral exploration... 

Fig. 1. Location map of the Collahuasi district (outlined) and geographic distribution of the outcrops of main igneous units of the Collahuasi Group in northern Chile. Ages for granitoids from the region are also shown (from Munizaga et a/. 2008 and references therein).

Collahuasi district, regional low-grade metamorphism affected most parts of northern Chile. To the west of the Collahuasi district, in the Coastal... 

Masterman, G.J. 2003. Structural and geochemical evolution of the Rosario Cu-Mo porphyry deposit and related Cu-Ag veins, Coiiahuasi district, northern Chile. PhD thesis. University of Tasmania, Tasmania, Australia. 

Munizaga, F., Maksaev, V., Fanning, C.M., Giglio, S., Yaxley, G., Tassinari, C.C.G. 2008. Late Paleozoic-Early Triassic magmatism on the western margin of Gondwana Coiiahuasi area. Northern Chile. Gondwana Research, 13, 407-427. 

Oliveros, V., Feraud, G. Aguire, L., Fornari, M., Morata, D. 2006. The Early Andean Magmatic Province (EAMP) ArmAr dating on Mesozoic volcanic and plutonic rocks from the Coastal Cordillera, northern Chile. Journal of Volcanology and Geothermal Research, 157, 31-330. 

Studies of the host rocks to giant porphyry copper deposits in Central and Northern Chile have shown that there are recognizable changes in the geochemistry of the volcanic rocks prior to mineralizing events (Skewes Stern 1995 Kay et al. 1999 Hollings et al. 2005). These include abrupt increases in the LaA b ratios of volcanic rocks associated with... 

Lithogeochemistry of the Quebrada Blanca Porphyry Cu Deposit, Atacama Desert, Northern Chile... 

CALICHE (Nitrate). The gravel, rock. soil, or alluvium cemented with soluble salts of sodium in the nitrate deposits of the Atacama Desert of northern Chile and Peru. The material contains from 14 to 25% sodium nitrate, 2 to 3% potassium nitrate, and up to I i sodium iodaic. plus some sodium chloride, sulfate, and borate. At one time, this was an important natural fertilizer. 

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