!? Sampling points Ordinary Kriging Prediction Map [Salar_border_new].[Li_concent] Contours Accessing the Genesis of -Rich Salt300 Pan Brines 400 by the Study of Chemical and Isotopic Compositions500 600 Nadja Schmidt, Broder Merkel 700 800 - TU Bergakademie Freiberg, Institute of Geology, Chair900 of Hydrogeology - 1.000 1.100 Ordinary Kriging Sampling points FilledLi [ppm Contours] !? Ordinary Kriging Introduction 200 - 300 ± Prediction Map 06-NOR 300 - 400 05-TAH pans are composed of layers, which can reach several 100 meters in thickness. [Salar_border_new].[Li_concent] 400 - 500 Pores in the salt crust are filled with a highly saline brine significantly enriched in lithium. The Contours 500 - 600 02-LLI 13-COR 01-COL 300 formation of salt pans with such characteristics is controlled by various processes including: 600 - 700 400 10-PES • Leaching of surrounding rocks and older underlying 700 - 800 08-CEN 500 • Rise of volcanic fluids 800 - 900 07-SAL 600 • Arid or semi arid climate 900 - 1.000 700 1.000 - 1.100 03-INC 04-YON800 1.100 - 1.200 900 1.000 09-RIO Investigations 0 3 6 12 18 24 1.100 Kilometers • Drillings to depths of <30 m performed at: Filled Contours Distribution200 - 300 of lithium in the interstitial brine of the  in the Bolivian upper 10 m (modeled by ArcGIS using Kriging) 300 - 400 Altiplano (high plateau between 400 - 500 Andean cordilleras) 500 - 600  Tuz Gölü, central Anatolia, Turkey 600 - 700 • Depth-dependant brine sampling 700 - 800 Sampling site (this study) • Determination of 800 - 900 Sampling site (Uygun & Sen 1978)  on-site parameters: pH, electrical 900 - 1.000 Left: Location of the Salar conductivity, O2, redox potential 1.000 - 1.100 de Uyuni in  main ions (IC), trace elements 1.100 - 1.200 (Fornari et al. 2001); (ICP-MS) Up: Satellite image of the 2 18 34 6 Tuz Gölü in Turkey (salt  stable isotopes: H, O, S, Li production plants in grey • Modeling of drainage basin by GIS scale) • Measurement of porosity (CT) and Analysis of on-site parameters in the field permeability (pumping tests, permeameter)

Results Mechanisms of enrichment 300 120 The brines are of NaCl type with mineralisations 250 100 The high lithium load in tributaries of the Salar de Uyuni of ~300 g/L (halite saturation). Lithium behaves conservative (concentration in solution points to the intensive weathering processes in Andean 200 80

rocks. Ion exchange processes in extensive floodplains increases with overall salinity).

lead to the release of lithium from clay minerals and the 150 60 Na [g/L] Na enrichment in the delta area of the Rio Grande. Wind [mg/L] Br Salar de Uyuni: Surrounding springs and transport contributes to the distribution of the enriched 100 40 tributaries are enriched in lithium, high brine on the surface. concentrations in the brine occur in the delta Br 50 20 18 The intensive solar insolation during the dry season Na area of main inflows. δD/δ O of interstitial leads to the evaporative concentration of the surface Linear (Na) brines plot on the local evaporation line. 0 0 , and thus, to the specific isotopic signature of 0 200 400 600 800 1.000 1.200 1.400 δD/δ18O in the brines. Li [mg/L] Tuz Gölü: A concentration gradient at the Concentration s of bromine and sodium in the Uyuni surface could not be observed, but content of brines in comparison to lithium contents -10 main ions increases with depth. Tributaries contribute only little to the enrichment of lithium -20 in the salt brine.

-30 Conclusions & Outlook Li [mg/L]

140 150 160 170 180 190 200 -40 The previous investigations show, that various mechanisms 0

-50 determine the enrichment and distribution of lithium in salt 2 [‰ SMOW] [‰

D D located at different climatic and geologic backgrounds.

δ -60 4

Uyuni brines Rio Grande -70 6

Altiplano lake [m] Depth Further investigations Li Linear (Uyuni brines) -80 8 LMWL include the precise Br LEL (Abbott et al. 2000) analysis of lithium 10 -90 -12 -10 -8 -6 -4 -2 0 2 4 6 isotopes and the δ18O [‰ SMOW] extension of sampling 12 Composition of δD/δ18O in the Salar de Uyuni 14 at the Tuz Gölü to a 600,00 650,00 700,00 750,00 800,00 brines compared to its tributary and Altiplano lake larger regional scale Br [mg/L] waters and the catchment Depth profile of lithium and bromine in the Tuz area. Gölü brines References View of the Salar de Uyuni from the island Abbott, M.B.; Wolfe, B.B.; Aravena, R. (2000) Holocene hydrological reconstructions of Incahuasi from stable isotopes and paleolimnology, Cordillera Real, Bolivia. Quaternary Science Reviews 19: 1801-1820

Fornari , M.; Risacher, F.; Féraud, G. (2001) Dating of paleolakes in the central Altiplano of Bolivia. Paleogeography, Paleoclimatology, Paleoecology 172: 269-282

Uygun, A.; Sen, E. (1978) The basin and natural resources I: Geochemistry Authors contacts: of the brine of the Salt Lake (Central Anatolia, Turkey). Bulletin of the Geological Dipl.-Geoökol. Nadja Schmidt ([email protected]) Society of Turkey 21: 113-120 Prof. Dr. Broder Merkel ([email protected])