Evolution and geochemical signatures in a Neogene forearc evaporitic basin: the Salar Grande (Central Andes of Chile)

Dı́az, Guillermo Chong; Mendoza, Mariángeles; Garcı́a-Veigas, Javier; Pueyo, Juan José; Turner, Peter

doi:10.1016/s0031-0182(99)00014-0

Cited by 50 publications

(33 citation statements)

References 13 publications

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“…Citing evidence given by Sáez et al (1999), Chong Díaz et al (1999), Gaupp et al (1999), and May et Hartley and Chong (2002) inferred that desiccation in the region from 19.75°S to 23ºS began before 3 Ma, but with much of it since that time (Fig. 6).…”

Section: South Americamentioning

confidence: 80%

Early Pliocene (pre–Ice Age) El Niño–like global climate: Which El Niño?

Molnár

Cane

2007

Geosphere

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Paleoceanographic data from sites near the equator in the eastern and western Pacifi c Ocean show that sea-surface temperatures, and apparently also the depth and temperature distribution in the thermocline, have changed markedly over the past ~4 m.y., from those resembling an El Niño state before ice sheets formed in the Northern Hemisphere to the present-day marked contrast between the eastern and western tropical Pacifi c. In addition, differences between late Miocene to early Pliocene (pre-Ice Age) paleoclimates and present-day average climates, particularly in the Western Hemisphere, resemble those associated with teleconnections from El Niño events, consistent with the image of a permanent El Niño state. Agreement is imperfect in that many differences between early Pliocene and present-day climates of parts of Africa, Asia, and Australia do not resemble the anomalies associated with canonical El Niño teleconnections. The teleconnections associated with the largest El Niño event in the past 100 yr, that in 1997-1998, do, however, reveal similar patterns of warming and the same sense, if not magnitude, of precipitation anomalies shown by differences between late Miocene-early Pliocene paleoclimates and present-day mean climates in these regions. If less consistent than those for the 1997-1998 event, temperature and precipitation anomalies correlated with the Pacifi c Decadal Oscillation also mimic many differences between early Pliocene and present-day climates. These similarities suggest that the sea-surface temperature distribution in the Pacifi c Ocean before Ice Age time resembled most that of the 1997-1998 El Niño, with the warmest region extending into the easternmost Pacifi c Ocean, not near the dateline as occurs in most El Niño events. This inference is consistent with equatorial Pacifi c proxy data indicating that at most a small east-west gradient in sea-surface temperature seems to have existed along the equator in late Miocene to early Pliocene time. Accordingly, such a difference in sea-surface temperatures may account for the large global differences in climate that characterized the earth before ice sheets became frequent visitors to the Northern Hemisphere.

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Section: South Americamentioning

confidence: 80%

Early Pliocene (pre–Ice Age) El Niño–like global climate: Which El Niño?

Molnár

Cane

2007

Geosphere

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“…The bounding regions of the Salar Grande (Cordillera de la Costa, regió n de Atacama, Chile) are characterized by saline subsoils associated with nitrate deposits that contain chlorides, sulfates, chlorates, chromates, iodates, and perchlorates. These salts are older and different from those of the more central region of the Salar Grande (Chong-Díaz et al, 1999).…”

Section: Introductionmentioning

confidence: 79%

“…Similar to events on Mars, harsh arid conditions promoted an extreme oversaturation of the ground and surface water solutions, which resulted in nearly exclusive precipitation of halite, the end member in evaporation from brines, with no other mineral phase (Chong-Díaz et al, 1999). The bounding regions of the Salar Grande (Cordillera de la Costa, regió n de Atacama, Chile) are characterized by saline subsoils associated with nitrate deposits that contain chlorides, sulfates, chlorates, chromates, iodates, and perchlorates.…”

Section: Introductionmentioning

confidence: 99%

A Microbial Oasis in the Hypersaline Atacama Subsurface Discovered by a Life Detector Chip: Implications for the Search for Life on Mars

et al. 2011

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The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5 m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2 m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5 g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260 g kg -1 ) and perchlorate (41.13 lg g -1 maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14 lg g -1 ) or formate (76.06 lg g -1 ) as electron donors, and sulfate (15875 lg g -1 ), nitrate (13490 lg g -1 ), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars.

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“…The 2005 campaign of the LITA experiment investigated life and its habitats at three sites in the Atacama (sites D, E, and F as illustrated in Figure 2). The Atacama Desert was selected for this rover field experiment because it bears several environmental and geological analogies to Mars: (1) arid, low temperature desert conditions, (2) magma‐water interactions and other hydrothermal activity, (3) evidence of tectonic processes, including fracturing, faulting, and basin formation, (4) presence of analogous materials, including igneous mineralogy and thick evaporite sequences, (5) structurally controlled basins and collapse‐related depressions, (6) landscape features related to aqueous processes such as sapping channels and alluvial fans, (7) landscape features related to climate‐driven aqueous processes such as flood‐carved terrain and dry lakebeds [e.g., Mouginis‐Mark , 1985, 1990; Baker et al , 1991; Scott et al , 1993, 1995; Tanaka et al , 1998, 2005; Chong Diaz et al , 1999; Dohm et al , 2001a, 2001b, 2001c, 2004; Cabrol et al , 2001b, 2007; Baker , 2001; Christensen et al , 2001; Fairén et al , 2003; Neukum et al , 2004; Márquez et al , 2004; Squyres et al , 2004; Gendrin et al , 2005; McSween et al , 2006; Warren‐Rhodes et al , 2007a, 2007b; Schultze‐Makuch et al , 2007]. The specific study sites within the Atacama were chosen to represent a spectrum of habitability, generally constrained by relative abundance of liquid water delivered to putative near‐surface habitats by fog, clouds, and potentially rain/snowfall.…”

Section: General Methodsmentioning

confidence: 99%

Life in the Atacama: A scoring system for habitability and the robotic exploration for life

et al. 2007

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[1] The science goals of the Life in the Atacama (LITA) robotic field experiment are to understand habitat and seek out life in the Atacama Desert, Chile, as an analog to future missions to Mars. To those ends, we present a new data analysis tool, the LITA Data Scoring System (DSS), which (1) integrates rover and orbital data relevant to environmental habitability and life detection, and (2) provides a standard metric, or ''score'' to evaluate (a) the potential habitability, and (b) the strength of evidence for life at all locales along the rover's traverse. Designed and tested during the 2005 field campaign, first results from the DSS indicate that the three selected sites in the Atacama Desert are generally inhospitable. The strength of evidence for life is positively correlated with potential habitability at two of the three sites. Using factor analysis, we find three factors explain 79.9% of the variance in biological observations and five factors explain 96.2% of the variance in potential habitability across all sites. These factors are used to focus a discussion of scoring variable definitions for future robotic missions in the Atacama and of instrument selection and strategy development for future robotic missions on Earth and Mars. Citation: Hock, A. N., et al. (2007), Life in the Atacama: A scoring system for habitability and the robotic exploration for life,

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Evolution and geochemical signatures in a Neogene forearc evaporitic basin: the Salar Grande (Central Andes of Chile)

Cited by 50 publications

References 13 publications

Early Pliocene (pre–Ice Age) El Niño–like global climate: Which El Niño?

Early Pliocene (pre–Ice Age) El Niño–like global climate: Which El Niño?

A Microbial Oasis in the Hypersaline Atacama Subsurface Discovered by a Life Detector Chip: Implications for the Search for Life on Mars

Life in the Atacama: A scoring system for habitability and the robotic exploration for life

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