Role of thermal waters in the formation of lithium deposits: a case study from Laguna Verde, Region of Atacama, Chile
Abstract
Laguna Verde (LV), a hypersaline lake within a salt flat, is located near San Francisco mountain pass between Chile and Argentina in the Andean Cordillera in the administrative Region of Atacama (Chile), 193 km east of the regional capital Copiapó. The study area was selected based on the presence of certain observations relevant to the formation of lithium deposits during the preliminary survey to assess geothermal potential of the area: (i) the presence of an active geothermal system with manifestation surface (thermal spring), (ii) presence of a hypersaline lake (LV) fed by rivers and springs, (iii) outcrop of likely source rocks of lithium at the border of LV, among others. Because lithium brines occur in similar conditions in other places as well, modeling the behavior of lithium at LV will serve as an excellent guide for exploration of lithium deposits formed in similar conditions. At LV, the main occurrence of lithium is within the hypersaline lake that has very high concentrations of lithium (~ 200 mg/l) and potassium (~ 5000 mg/l). The lake is fed by active springs that seem to be the main transporter of lithium, potassium, and other metal salts. Although the presence of a geothermal system is not an exclusive requirement for the formation of lithium brine, geothermal fluids can release lithium with greater efficiency, through accelerated dissolution of acidic volcanic rocks rich in lithium, dissolving this element selectively. West of LV, rhyolitic-dacitic pyroclastic flow deposits are composed of at least four units with intercalation of at least two levels of pyroclastic surge collations. Flow units correspond to tuffs with varying proportions of young pumice fragments (medium to pump lapilli-sized) and subrounded to angular lithic fragments of andesites and dacites immersed in a fine matrix, white to pink in color and lightly to heavily compacted. Wavy units correspond to tuffs with cross-lamination, dunes and lenses of different particle size. These formations are interesting, as rhyolite and dacites are potential sources of lithium. The results of the modeling of physicochemical processes that control the release of lithium from the rocks sources by geothermal fluids will be presented during meeting.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPA41C1136A
- Keywords:
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- 0215 Economic geology;
- GEOHEALTH;
- 3665 Mineral occurrences and deposits;
- MINERALOGY AND PETROLOGY;
- 6324 Legislation and regulations;
- POLICY SCIENCES;
- 6314 Demand estimation;
- POLICY SCIENCES & PUBLIC ISSUES