The origin of continental carbonates in Andean salars: A multi-tracer geochemical approach in Laguna Pastos Grandes (Bolivia)

Muller, Elodie; Gaucher, Éric C.; Durlet, Christophe; Moquet, Jean-Sébastien; Moreira, Manuel; Rouchon, Virgile; Louvat, Pascale; Bardoux, Gérard; Noirez, Sonia; Bougeault, Cédric; Vennin, Emmanuelle; Gérard, Emmanuelle; Chavez, Marco; Virgone, Aurélien; Ader, Magali

doi:10.1016/j.gca.2020.03.020

Cited by 9 publications

(26 citation statements)

References 76 publications

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“…The exceptional production of carbonates in this purely volcanic area could thus be explained by hypogean boosting of the sedimentary system. In fact, the CO 2 delivered by hydrothermal springs is from 60 to 389 mbar, equal to or higher than the amount at other Andean sites (see Reference [16]).…”

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 92%

“…The palustrine area is characterized by a carbonate-rich platform (approximately 40 km 2 , up to 30 cm thick), fragmented by frost action [12], which is the largest carbonate platform in the Altiplano, where carbonate deposits are rare and restricted to smaller areas. As recently demonstrated, it results from hydrothermal fluids that deliver large quantities of CO 2 and Ca ++ originating from the hydrothermal alteration of the volcanic basement in the presence of CO 2 [16]. Established models suggest that CO 2 comes exclusively from magmatism, deriving partly from the mantle (47%), indicating a deep origin for this gas.…”

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 92%

“…The carbon and oxygen isotope compositions of the carbonates (δ 18 O carb , δ 13 C carb , and 14 C) were acquired specifically for this study, while the data for water chemistry and stable isotopes (δ 13 C gas , δ 13 C DIC -dissolved inorganic carbon, and δ 18 O water ) from hydrothermal springs, piedmont sources, ephemeral streams, and the lake itself were taken from Muller et al [16]. As no data were available for the depositional environments where the pisolites, palmatoid concretions, and platystromatolites formed, additional physicochemical measurements from the pools (i.e., temperature, pH, and conductivity) were acquired in situ with a Hach HQ40D Multi-instrument (Hach Company, Loveland, CO, USA).…”

Section: Methodsmentioning

confidence: 99%

“…The recharge in chemical elements is thought to occur at 225 • C, based on geothermometers, corresponding to a depth of about 5 km [16], and may be triggered by the volcanic chamber under the laguna [22]. These hydrothermal fluids then rise to the surface through fractures [16]. The exceptional production of carbonates in this purely volcanic area could thus be explained by hypogean boosting of the sedimentary system.…”

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 98%

“…Established models suggest that CO 2 comes exclusively from magmatism, deriving partly from the mantle (47%), indicating a deep origin for this gas. The recharge in chemical elements is thought to occur at 225 • C, based on geothermometers, corresponding to a depth of about 5 km [16], and may be triggered by the volcanic chamber under the laguna [22]. These hydrothermal fluids then rise to the surface through fractures [16].…”

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 99%

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Variability of Carbonate Isotope Signatures in a Hydrothermally Influenced System: Insights from the Pastos Grandes Caldera (Bolivia)

et al. 2020

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Laguna Pastos Grandes (Bolivia), nesting in a volcanic caldera, is a large, palustrine-to-lacustrine system fed by meteoric and hydrothermal calco–carbonic fluids. These different fluid inputs favor a complex mosaic of depositional environments, including hydrothermal springs, pools, and an ephemeral lake, producing abundant present-day carbonates developing over a Holocene carbonate crust dated by U–Th. Present-day carbonates (muds, concretions, and microbialites) recorded a large range of isotope variations, reaching 13.9‰ in δ13C and 11.1‰ in δ18O. Sedimentological and geochemical data indicated that the main processes influencing the isotope record were: (i) rapid CO2 degassing and temperature decreases along hydrothermal discharges; (ii) strong evaporation favored by the arid high-altitude Andean climate, locally enhanced by capillary water rise within microbial mats or by wind-induced spray falling on vadose concretions. Unlike past or present perennial lake systems in Central Andes, the short residence time of brine waters in the ephemeral central lake prevents enrichment of lacustrine carbonates in 13C and 18O. The very low fraction modern F14C in these present-day carbonates demonstrates that incorporation of fossil magmatic carbon related to the volcanic context also prevents any radiocarbon dating. The use of isotopes for the interpretation of ancient continental series should always be accompanied by a thorough characterization of the environmental setting.

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Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 92%

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 98%

Section: Regional Background Volcanic Setting and Carbonate Facies Of The Pastos Grandes Areamentioning

confidence: 99%

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Variability of Carbonate Isotope Signatures in a Hydrothermally Influenced System: Insights from the Pastos Grandes Caldera (Bolivia)

et al. 2020

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Lithium enrichment in the Salar de Diablillos, Argentina, and the influence of Cenozoic volcanism in a basin dominated by Paleozoic basement

et al. 2023

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Salars with lithium-rich brines are a characteristic feature of the Central Andes, but knowledge about the main sources of lithium and the mobilization processes of lithium in the salar deposits is still incomplete. This work focuses especially on the Salar de Diablillos (southern Puna) as part of a larger area that includes the neighboring Salar Centenario and Salar de Ratones. Building on the ability of Li as a tracer of silicate weathering, we investigate the Li content and isotope composition of samples from the depocenter and catchment of the Diablillos basin (3-D) and conduct a surface reconnaissance in the Centenario and Ratones depocenters to identify the key metallogenic processes. Radiogenic Sr and Nd isotope compositions are also provided to discriminate the main local Li sources. The isotope data in all three depocenters show that most of the Li in the brines and evaporite deposits are derived from Cenozoic volcanic rocks, despite the dominance of the Paleozoic basement in the catchment. In the Centenario and Ratones depocenters, near-surface chemical weathering appears to be the dominant Li mobilization process. In contrast, hydrothermal mobilization of Li also plays a role in the Salar de Diablillos, possibly related to the presence of a fractured basement with pressure zones and artesian conditions in the aquifer at depth. These fluids also show a larger element contribution from the basement.

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Exploring the geochemical mechanism for the saturated permeability change of remolded loess

Zhang

Qian

et al. 2021

Engineering Geology

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The origin of continental carbonates in Andean salars: A multi-tracer geochemical approach in Laguna Pastos Grandes (Bolivia)

Cited by 9 publications

References 76 publications

Variability of Carbonate Isotope Signatures in a Hydrothermally Influenced System: Insights from the Pastos Grandes Caldera (Bolivia)

Variability of Carbonate Isotope Signatures in a Hydrothermally Influenced System: Insights from the Pastos Grandes Caldera (Bolivia)

Lithium enrichment in the Salar de Diablillos, Argentina, and the influence of Cenozoic volcanism in a basin dominated by Paleozoic basement

Exploring the geochemical mechanism for the saturated permeability change of remolded loess

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