El salar de Río Grande (Salta) y su depósito de sodio.

LUCÍA, F.J.; ALONSO, R.N.; QUIROGA, A.G.; RUIZ, T. DEL V.

Río Cuarto, Córdoba

Congreso; X Congreso de Mineralogía y Metalogenia; 2010

Asociación Mineralógica Argentina y Universidad Nacional de Río Cuarto

The Rio Grande salt pan is an evaporitic environment situated in the southern Puna, Salta province, close to the borders of Catamarca province and Chile (25° 03’ S and 68° 12’ W, 3670 m.a.s.l.). It covers a surface of 165 km2. The main geological setting is composed by volcanic rocks and red-beds all Neogene in age. The interior of the salar is formed by calcium sulfate, sodium sulfate and sodium chloride evapofacies. The identified mineral species are halite, gypsum, thenardite, mirabilite, hidroglauberite, and eugsterite. Brines have interesting contents of lithium (400 ppm) and potassium (7400 ppm). We present here the results of 40 drill holes, some of them until 32 m deep. The holes, made in the depocenter of the salt pan, have identified mirabilite rich deposit of 5 m thick, 90% pure mineral. The origin of the sodium sulfate is directly related with the nearest native sulfur rich volcanoes. The sulfur was lixiviated to the closed basin of Rio Grande were had produced sodium and calcium sulfate. Likewise, thermal springs along faults in the border of the salt pan, were the source of another chemical elements. Rio Grande is the main sodium sulfate deposit of Argentina and South America.