Century scale rainfall in the absolute Atacama Desert: Landscape response and implications for past and future rainfall

Pfeiffer, Marco; Morgan, A. M.; Heimsath, Arjun M.; Jordan, Teresa E.; Howard, A. D.; Amundson, R.

doi:10.1016/j.quascirev.2021.106797

Cited by 59 publications

(42 citation statements)

References 75 publications

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“…This was the case in the most recent rain event previous to our sampling in March 2015 (Jordan et al, 2015;Bozkurt et al, 2016). Over 30 mm of total rain caused soil moistening over months, as well as surface overland run-off on hillslopes, subsurface flow, and change in soil mineralogy in our study region (Jordan et al 2020;Pfeiffer et al, 2021). This rain event was followed by a rain event with a similar magnitude in 2017, which is discussed as a consequence of global climate change (Azua-Bustos et al, 2018).…”

Section: Study Site Selection and Samplingmentioning

confidence: 56%

“…More recently, Voigt et al (2020) have shown in the Atacama Desert a correlation between the regional aridity and the occurrences of anhydrite and gypsum within surface-near soils (< 40 cm depth) located between 25°S and 19°S latitudes, where anhydrite dominated in the northern, most arid regions. Other studies have found a shift of hydration phases of near-surface calcium sulfates after the extreme rain event in 2015 (e.g., Schulze-Makuch et al, 2018;Pfeiffer et al, 2021). Considering the proposed dehydration of gypsum after a rain event by high surface temperatures reaching 60°C, Pfeiffer et al (2021) concluded that the uppermost chusca horizon is subject to rapid dehydration-hydration cycles.…”

Section: Gypsum Vs Anhydritementioning

confidence: 95%

“…The HD and TD soil profiles located on inactive alluvial fan deposits correspond well to the hyperarid soil type described by Ericksen (1981). Due to the gentle slope and porous chusca horizon surface, rainwater usually infiltrates entirely into the subsurface (Pfeiffer et al, 2021;Sager et al, 2021). As a result of minimal erosion, the accumulation of salts results in a net deposition (Ewing et al, 2006).…”

Section: Elevation-related Soil Attributesmentioning

confidence: 99%

“…These observations are consistent with a formation mechanism of the vesicular layer mediated through repetitive eolian input of clays and salts as well as little rainwater infiltration and evaporation; a formation process also proposed for the analogous carbonate-rich vesicular layer found in the arid soils of the Mojave Desert, North America (McFadden et al, 1998;Anderson et al, 2002). In the case of the hyperarid Atacama Desert the cooccurring salt dissolution and reprecipitation, as well as hydration and dehydration of sulfates can play an important role in the formation of vesicular structure (Pfeiffer et al, 2021).…”

Section: Elevation-related Soil Attributesmentioning

confidence: 99%

“…The porous and permeable chusca horizon is most frequently exposed to meteoric water and therefore is the most dynamic horizon, which could explain why measured isotopic fractionation is stronger than seen in the modeled data. This upper soil horizon is also affected by salt efflorescence after rain events and through artificial rain experiments (Sager et al, 2021, Pfeiffer et al, 2021, which indicates more complex water pathways at the surface than dominant downward migration, influencing potentially also the isotopic fractionation. Furthermore, rainwater infiltration is not homogeneous and is most intense along the sand wedges (Owen et al, 2013), presumably affecting the lateral isotope pattern.…”

Section: Water-soil Interactionsmentioning

confidence: 99%

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Geochemical proxies for water-soil interactions in the hyperarid Atacama Desert, Chile

Arens

Airo

Feige

et al. 2021

CATENA

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The Atacama Desert is the oldest and driest non-polar desert on Earth. Millions of years of hyperaridity enabled salt accumulations through atmospheric deposition. These salts can serve as proxies to decipher the interaction between water and soil as well as to understand the habitability with changing environmental settings. Therefore, we investigated four soil profiles regarding their mineralogy, salt abundance, and sulfate stable isotopic composition. The profiles were located along an elevation transect in the hyperarid region southeast of Antofagasta, Chile. The two lower sites situated on the distal parts of inactive alluvial fan deposits were subject to occasional fog occurrences. The upper steeper-sloped sites experienced no fog but are subject to minimal erosion. In all soil profiles, sulfates are the dominant salts showing a downward transition from gypsum to anhydrite that is accompanied by an increase of highly soluble salts and a decrease of sulfate δ 34 S and δ 18 O values. These trends are consistent with downward directed water infiltration during rare rain events causing salt dissolution followed by precipitation within the deeper soil column. This conclusion is also w supported by our Rayleigh fractionation model. We attribute the presence of anhydrite at > 40 cm depth to the cooccurrence of nitrate and chloride salts, which decreases water activity during sulfate precipitation and therefore drives anhydrite formation. Along the elevation transect, the total salt inventories of each profile show a trend for nitrates and chlorides concentration decreasing with elevation. This observation together with the sulfate stable isotopes indicates a fog-independent source and suggests remobilization of soluble salts through enhanced washout from hillslopes to alluvial fans. These findings are essential for assessing the longterm regional habitability of hyperarid environments and have also relevance for Mars.

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Section: Study Site Selection and Samplingmentioning

confidence: 56%

Section: Gypsum Vs Anhydritementioning

confidence: 95%

Section: Elevation-related Soil Attributesmentioning

confidence: 99%

Section: Elevation-related Soil Attributesmentioning

confidence: 99%

Section: Water-soil Interactionsmentioning

confidence: 99%

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Geochemical proxies for water-soil interactions in the hyperarid Atacama Desert, Chile

Arens

Airo

Feige

et al. 2021

CATENA

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Exceptional preservation in Quaternary Atacama Desert Tufas: Evidence for increased groundwater and surface water in the Calama Basin, Atacama, Chile

Wet

Driscoll

Wet

et al. 2023

The Depositional Record

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Exceptionally well‐preserved tufas located west of Calama, Atacama Desert, Chile, designated Santa Juana tufas, record episodic wetter conditions, relative to today, over the past 500,000 years. Globally, tufa architecture and depositional details are poorly understood as most described tufas have been degraded by weathering and erosion. In the hyperarid Atacama, post‐depositional alteration is negligible, therefore, the exceptional preservation of Santa Juana tufas documented in this study provides new information about tufa facies and their complex interactions. Santa Juana facies include microbial stromatolites, phytoherms, cascadestone, flowstone and porous limestone. Phytoherms, consisting of former plant stems coated with calcite, developed in channels, within pools, and along spring discharge aprons. Cascadestone, representing former waterfalls, preserves microbial filaments and delicate V‐shaped calcite crystals. Flowstone lines shallow subvertical to subhorizontal channels, representing sites of rapidly sluicing water flow. Porous limestone, containing sparse calcite and/or gypsum and anhydrite cement crystals, represents detrital accumulations. Stable isotope results, coupled with U/Th ages, show that by the Quaternary, relative to the Neogene, groundwater was less supercharged with volcanogenic CO2 so degassing was moderated. The δ18O ratios from Miocene–Pliocene palustrine and lacustrine freshwater carbonates that underlie Santa Juana tufas indicate significant evaporation, but the tufa δ18O signal indicates a less evaporative trend due to shorter atmosphere exposure time. Biological fractionation in δ13C is largely masked by the region's volcanogenic carbon footprint, although tufa petrography shows well‐preserved microbial filaments and laminations. The range of tufa ages in this study shows that there were wetter time periods within the drainage basin headwater area in the Quaternary, but that by the late Pleistocene to early Holocene, aridity to hyperaridity became established. The lack of diagenesis or alteration within the Santa Juana tufas indicates that there has been minimal rainfall since their deposition.

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Crop Improvement in the Desert

Shehzadi,

Ishfaq,

Mahmood

et al. 2023

Climate-Resilient Agriculture, Vol 1

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Century scale rainfall in the absolute Atacama Desert: Landscape response and implications for past and future rainfall

Cited by 59 publications

References 75 publications

Geochemical proxies for water-soil interactions in the hyperarid Atacama Desert, Chile

Geochemical proxies for water-soil interactions in the hyperarid Atacama Desert, Chile

Exceptional preservation in Quaternary Atacama Desert Tufas: Evidence for increased groundwater and surface water in the Calama Basin, Atacama, Chile

Crop Improvement in the Desert

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