On the origin of saline compounds in acidic salt flats (Central Andean Altiplano)

Pueyo, Juan José; Demergasso, Cecilia; Escudero, Lorena; Chong, Guillermo; Cortéz-Rivera, Paulina; Sanjurjo-Sánchez, Jorge; Carmona, V.; Giralt, Santiago

doi:10.1016/j.chemgeo.2021.120155

Cited by 5 publications

(10 citation statements)

References 153 publications

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“…The hydrological progression from active lagoons to exposed salt paleoterraces forms a natural climate-transition experiment, where each salar surface represents a different stage of evolution in the wet-to-dry transitions during (micro-)cycles of climate change over geological time scales. The climate transition exemplified at Salar de Pajonales partly mirrors that postulated for early Mars (Kite, 2019;Wordsworth et al, 2021), thus making it a unique terrestrial analog for early climate change on that planet (Cabrol et al, 2009;Cabrol, 2018;Farías and Acuña, 2020;Pueyo et al, 2021).…”

Section: Introductionmentioning

confidence: 81%

“…Lake levels in the Altiplano reached their maximum between 10.8 and 9.2 ka and disappeared sometime between 8.4 and 8.0 ka (Geyh et al, 1999). Since then, the climate has been extremely arid except for brief wetter periods, the most recent being probably from the same time (1.39+/− 0.10 ka) as that of the Gorbea and Ignorado salt flats located ∼40 km south of Salar de Pajonales and at higher elevation (Figure 1; ∼4000 m asl (Pueyo et al, 2021). Other climate records, found in fossilized rodent middens, wetland deposits, and archeological sites also reflect wetter time periods within the last 90 ka (Chepstow-Lusty et al, 2005;Maldonado et al, 2005;Díaz et al, 2012;Pfeiffer et al, 2021).…”

Section: Climatementioning

confidence: 97%

“…Salar de Pajonales is a hydrologically active evaporitic system. Brines that fill the remaining active lagoons in the lower elevation portions of Salar de Pajonales are formed by a combination of atmospheric aerosol input, volcanic emissions, chemical weathering of country rock, and high rates of evaporation relative to precipitation (Risacher et al, 2003;Chong Diaz et al, 2020;Otalora et al, 2020;Pueyo et al, 2021). During the transition to the more arid climate of today, episodic evaporation of the brines and inundation of the basin left an evaporite package several meters thick (Figure 2; see below).…”

Section: Site Overviewmentioning

confidence: 99%

“…During the transition to the more arid climate of today, episodic evaporation of the brines and inundation of the basin left an evaporite package several meters thick (Figure 2; see below). At present, the basin receives recharge from both surface water (Risacher et al, 2003) and, by inference from other endorheic basins, groundwater, which originates from the volcanic arc of the Andes to the east (Urrutia et al, 2018;Chong Diaz et al, 2020;Pueyo et al, 2021).…”

Section: Site Overviewmentioning

confidence: 99%

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Surface Morphologies in a Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile

Hinman

Hofmann

Warren-Rhodes

et al. 2022

Front. Astron. Space Sci.

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Salar de Pajonales, a Ca-sulfate salt flat in the Chilean High Andes, showcases the type of polyextreme environment recognized as one of the best terrestrial analogs for early Mars because of its aridity, high solar irradiance, salinity, and oxidation. The surface of the salar represents a natural climate-transition experiment where contemporary lagoons transition into infrequently inundated areas, salt crusts, and lastly dry exposed paleoterraces. These surface features represent different evolutionary stages in the transition from previously wetter climatic conditions to much drier conditions today. These same stages closely mirror the climate transition on Mars from a wetter early Noachian to the Noachian/Hesperian. Salar de Pajonales thus provides a unique window into what the last near-surface oases for microbial life on Mars could have been like in hypersaline environments as the climate changed and water disappeared from the surface. Here we open that climatological window by evaluating the narrative recorded in the salar surface morphology and microenvironments and extrapolating to similar paleosettings on Mars. Our observations suggest a strong inter-dependence between small and large scale features that we interpret to be controlled by extrabasinal changes in environmental conditions, such as precipitation-evaporation-balance changes and thermal cycles, and most importantly, by internal processes, such as hydration/dehydration, efflorescence/deliquescence, and recrystallization brought about by physical and chemical processes related to changes in groundwater recharge and volcanic processes. Surface structures and textures record a history of hydrological changes that impact the mineralogy and volume of Ca-sulfate layers comprising most of the salar surface. Similar surface features on Mars, interpreted as products of freeze-thaw cycles, could, instead, be products of water-driven, volume changes in salt deposits. On Mars, surface manifestations of such salt-related processes would point to potential water sources. Because hygroscopic salts have been invoked as sources of localized, transient water sufficient to support terrestrial life, such structures might be good targets for biosignature exploration on Mars.

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Section: Introductionmentioning

confidence: 81%

Section: Climatementioning

confidence: 97%

Section: Site Overviewmentioning

confidence: 99%

Section: Site Overviewmentioning

confidence: 99%

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Surface Morphologies in a Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile

Hinman

Hofmann

Warren-Rhodes

et al. 2022

Front. Astron. Space Sci.

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“…Additional sulphate minerals (jarosite, alunite and minor amounts of anhydrite) have been observed in other nearby salars (Salar de Gorbea: Bennison, 2019;Pueyo et al, 2021), but neither jarosite nor alunite has been observed in the linings and tumuli at SdP, suggesting that the originally low pH of the volcanic gases (due to the oxidation and dissolution of SO 2 and the dissolution of CO 2 ) was at least partially neutralized prior to entering the tumuli chamber. This buffering process might have started during early degassing in reactions with brines or saline groundwaters (e.g.…”

Section: Breached Tumulimentioning

confidence: 98%

Gypsum‐lined degassing holes in tumuli

Hofmann,

Hinman,

Phillips

et al. 2023

Earth Surf Processes Landf

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Small, circular holes, lined with a thin gypsum veneer, and closely associated with gypsum tumuli (domes), occur at Salar de Pajonales, a salt flat in the northern Andes, Chile. We propose a model in which the formation of the gypsum‐lined holes, and less commonly the formation of the tumuli itself, is controlled by the unique juxtaposition of physiographic, geologic and hydrologic conditions. On a regional scale, Salar de Pajonales is unusual compared to other salars, as it is located close to a large magmatic inflation centre (Lazufre), lies along strike of major regional structural trends, is a large ephemeral lake and contains high salt concentrations. On a basin scale, the lined holes are only present along strike of lineaments that are directly linked to the local stress regime. In turn, these lineaments control the location of degassing and subsequently the formation of the lined holes in the gypsum tumuli and, in part, the tumuli themselves.

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Physical, chemical, and microbial feedbacks controlling brine geochemistry and lake morphology in polyextreme salar environments

Oehlert

Suosaari

Kong

et al. 2022

Science of The Total Environment

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On the origin of saline compounds in acidic salt flats (Central Andean Altiplano)

Cited by 5 publications

References 153 publications

Surface Morphologies in a Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile

Surface Morphologies in a Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile

Gypsum‐lined degassing holes in tumuli

Physical, chemical, and microbial feedbacks controlling brine geochemistry and lake morphology in polyextreme salar environments

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