Smectite synthesis at low temperature and neutral pH in the presence of succinic acid

Bontognali, Tomaso R. R.; Ruiz, Francisca Martínez; McKenzie, Judith A.; Bahniuk, Anelize; Anjos, Sylvia; Vásconcelos, Crisógono

doi:10.1016/j.clay.2014.09.018

Cited by 21 publications

(13 citation statements)

References 24 publications

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“…Similarly, Bontognali et al (Bontognali et al, 2014) demonstrated that the presence of certain organic acids (e.g., succinic acid) enhanced the precipitation of smectite, but others (e.g., oxalic and citric acid) had no influence or inhibited nucleation. Succinic acid is a common product of the degradation of organic macromolecules by aerobic micro-organisms and thus can be found in EPS of natural mats (Krebs, 1970).…”

Section: Mg-si Phasementioning

confidence: 99%

Formation of stromatolite lamina at the interface of oxygenic–anoxygenic photosynthesis

et al. 2018

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In modern stromatolites, mineralization results from a complex interplay between microbial metabolisms, the organic matrix, and environmental parameters. Here, we combined biogeochemical, mineralogical, and microscopic analyses with measurements of metabolic activity to characterize the mineralization processes and products in an emergent (<18 months) hypersaline microbial mat. While the nucleation of Mg silicates is ubiquitous in the mat, the initial formation of a Ca-Mg carbonate lamina depends on (i) the creation of a high-pH interface combined with a major change in properties of the exopolymeric substances at the interface of the oxygenic and anoxygenic photoautotrophic layers and (ii) the synergy between two major players of sulfur cycle, purple sulfur bacteria, and sulfate-reducing bacteria. The repetition of this process over time combined with upward growth of the mat is a possible pathway leading to the formation of a stromatolite.

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Section: Mg-si Phasementioning

confidence: 99%

Formation of stromatolite lamina at the interface of oxygenic–anoxygenic photosynthesis

et al. 2018

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“…Besides acting as a nucleation site, the EPS matrix concentrates specific cations creating local microenvironments that favor supersaturation and precipitation of carbonate minerals (Dupraz et al, 2009). The early stage of mineral nucleation within EPS is often characterized by the formation of nanoglobules (Riding, 2000;Benzerara et al, 2006;Bontognali et al, 2008;Sánchez-Román et al, 2014) and by the presence of an amorphous Mg-silicate (Léveillé et al, 2000;Arp et al, 2003;Bontognali et al, 2010Bontognali et al, , 2014Burne et al, 2014;Zeyen et al, 2015). Both features are observable in the mushroom cap in combination with the partially mineralized EPS microstructures (Figure 3B), suggesting that the cap facies may have formed through a microbiallyinfluenced mineralization process similar to that occurring in many microbialite-producing microbial mats (Dupraz et al, 2009).…”

Section: Model For Mushroom Speleothem Formationmentioning

confidence: 99%

Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs

et al. 2016

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Unusual speleothems resembling giant mushrooms occur in Cueva Grande de Santa Catalina, Cuba. Although these mineral buildups are considered a natural heritage, their composition and formation mechanism remain poorly understood. Here we characterize their morphology and mineralogy and present a model for their genesis. We propose that the mushrooms, which are mainly comprised of calcite and aragonite, formed during four different phases within an evolving cave environment. The stipe of the mushroom is an assemblage of three well-known speleothems: a stalagmite surrounded by calcite rafts that were subsequently encrusted by cave clouds (mammillaries). More peculiar is the cap of the mushroom, which is morphologically similar to cerebroid stromatolites and thrombolites of microbial origin occurring in marine environments. Scanning electron microscopy (SEM) investigations of this last unit revealed the presence of fossilized extracellular polymeric substances (EPS)-the constituents of biofilms and microbial mats. These organic microstructures are mineralized with Ca-carbonate, suggesting that the mushroom cap formed through a microbially-influenced mineralization process. The existence of cerebroid Ca-carbonate buildups forming in dark caves (i.e., in the absence of phototrophs) has interesting implications for the study of fossil microbialites preserved in ancient rocks, which are today considered as one of the earliest evidence for life on Earth.

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“…Petrographic observations indicated that EPS influenced both dolomite and clay authigenesis at the study site (Figures 6E-6H). However, Bontognali et al (2014b) demonstrated microbial mineralization of smectite in laboratory experiments, while others (e.g. The presence of Mg-clays connecting and replacing with EPS structures surrounding the dolomite suggests the clay formation was also promoted by EPS and was closely related to dolomite precipitation.…”

Section: Origin Of Dolomitementioning

confidence: 96%

“…Microbial influence upon clay authigenesis has not been as fully explored. However, Bontognali et al (2014b) demonstrated microbial mineralization of smectite in laboratory experiments, while others (e.g. Casado et al, 2014;Wanas and Sallam, 2016) have suggested that incipient Mg-clay formation may be important for dolomite precipitation, with early viscous clay material further promoting nucleation.…”

Section: Origin Of Dolomitementioning

confidence: 97%

Geomorphic and hydrological controls on groundwater dolocrete formation in the semi‐arid Hamersley Basin, northwest Australia

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Dogramaci

et al. 2019

Earth Surf Processes Landf

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Groundwater dolocretes may exert an important geomorphic control on landscape evolution within sub‐humid to arid regions. However, the geomorphic and hydrogeological settings of dolocrete remain poorly described. The hydrochemical conditions of dolomite precipitation in groundwater environments are also not well known. Classic models of dolocrete formation explain dolomite precipitation from highly evolved groundwaters at the terminus of major drainage but do not explain dolocrete distributed in regionally elevated landscapes, upgradient of major drainage. This study investigated the mineralogy, micromorphology and stable carbon and oxygen isotope compositions of three dolocrete profiles within a regionally elevated sub‐basin of the Hamersley Ranges in the Pilbara region of northwest Australia. We sought to establish the environmental and hydrochemical conditions and present a model for dolocrete formation. We found that dolocrete formed within zones of emerging groundwater under saline‐evaporitic conditions within internally draining sub‐basins, most likely during the Late Miocene and Pliocene. Saline‐evaporitic conditions were indicated by: (i) the mineralogy, dominated by dolomite, palygorskite and smectite; (ii) desiccation features and the presence of phreatic and vadose cements, indicative of a shallow fluctuating water table, and; (iii) dolomite δ18O values (median = –5.88 ‰). Dolomite precipitation was promoted by evaporation and carbon dioxide degassing from shallow magnesium (Mg)‐rich groundwater. These factors appear to have been the major drivers of dolocrete development without a requirement for significant down‐dip hydrochemical modification. Primary dolomite precipitation was possible due to the presence of microbial extracellular polymeric substances (EPS). EPS provided negatively charged nucleation sites, which bound Mg2+, overcoming kinetic effects. High microbial activity within groundwater systems suggest these processes may be important for dolocrete formation worldwide and that groundwater dolocretes may be more pervasive in landscapes than currently recognized. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.

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Smectite synthesis at low temperature and neutral pH in the presence of succinic acid

Cited by 21 publications

References 24 publications

Formation of stromatolite lamina at the interface of oxygenic–anoxygenic photosynthesis

Formation of stromatolite lamina at the interface of oxygenic–anoxygenic photosynthesis

Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs

Geomorphic and hydrological controls on groundwater dolocrete formation in the semi‐arid Hamersley Basin, northwest Australia

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