Identification of nanocrystalline goethite in reduced clay formations: Application to the Callovian-Oxfordian formation of Bure (France)

Kars, Myriam; Lerouge, Cathérine; Grangeon, Sylvain; Aubourg, Charles; Tournassat, Christophe; Madé, Benoı̂t; Claret, Francis

doi:10.2138/am-2015-5096

Cited by 14 publications

(10 citation statements)

References 40 publications

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“…Two mineralogically distinct phase assemblages are distinguished. The first and largest group of samples is described as colloids in amorphous clay (allophane) (Kars et al, 2015) clusters, surface coatings on particles, and interstitial soils, characterized here by an average Fe / Al ratio of 0.94 (range 0.41-3.78). The Fe and Al contents as well as the Fe / Al ratios are evidence of interstitial layers of iron (goethite) and aluminum (gibbsite), oxyhydroxides (Birkeland, 1999), and possibly the presence of nano-sized colloidal particles of oxides (hematite).…”

Section: Discussionmentioning

confidence: 99%

“…17) and the high correlation coefficient of 0.79 between Fe and Al (Table 1) point to a strong chemical interrelationship amongst the Fe-bearing clays, Fe-oxides (goethite, hematite, magnetite), and other silicates such as micas (biotite, muscovite) and chlorite. Recent studies (Reynolds et al, 2014a, b;Kars et al, 2015), applying a combination of Mössbauer spectroscopy, magnetic measurements, reflectance spectroscopy, and scanning electron microscopy (SEM), provide evidence of nanometer size (< 20 nm) particles of hematite, goethite, and magnetite associated with clay particles. Similarly, from magnetic measurements on the Callovian-Oxfordian claystones in the Paris Basin, Kars et al (2015) suggest nanoparticles of goethite to be dispersed in the clay-like matrix.…”

Section: Simentioning

confidence: 99%

“…Recent studies (Reynolds et al, 2014a, b;Kars et al, 2015), applying a combination of Mössbauer spectroscopy, magnetic measurements, reflectance spectroscopy, and scanning electron microscopy (SEM), provide evidence of nanometer size (< 20 nm) particles of hematite, goethite, and magnetite associated with clay particles. Similarly, from magnetic measurements on the Callovian-Oxfordian claystones in the Paris Basin, Kars et al (2015) suggest nanoparticles of goethite to be dispersed in the clay-like matrix. Fordham (1990), from investigations by electron microscopy and XRD, concluded that biotite underwent chemical weathering at particle edges and along cleavage plains to form finely divided interstratified flakes of illite and iron oxides in the clay-like matrix, which Borchard et al (1971) had identified as colloidal coatings of amorphous clay-like particles in volcanic ash in soils.…”

Section: Simentioning

confidence: 99%

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Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

et al. 2016

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Abstract. This paper promotes an understanding of the mineralogical, chemical, and physical interrelationships of re-suspended mineral dusts collected as grab samples from global dust sources. Surface soils were collected from arid regions, including the southwestern USA, Mali, Chad, Morocco, Canary Islands, Cabo Verde, Djibouti, Afghanistan, Iraq, Kuwait, Qatar, UAE, Serbia, China, Namibia, Botswana, Australia, and Chile. The <  38 µm sieved fraction of each sample was re-suspended in a chamber, from which the airborne mineral dust could be extracted, sampled, and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size analyzer, and a three-wavelength (405, 532, 781 nm) photoacoustic instrument with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sampling media included Teflon® membrane and quartz fiber filters for chemical analysis and Nuclepore® filters for individual particle analysis by scanning electron microscopy (SEM). The <  38 µm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the >  75, <  125 µm soil fractions were mineralogically assessed by optical microscopy. Presented here are results of the optical measurements, showing the interdependency of single-scattering albedos (SSA) at three different wavelengths and mineralogical content of the entrained dust samples. To explain the elevated concentrations of iron (Fe) and Fe ∕ Al ratios in the soil re-suspensions, we propose that dust particles are to a large extent composed of nano-sized particles of micas, clays, metal oxides, and ions of potassium (K+), calcium (Ca2+), and sodium (Na+) evenly dispersed as a colloid or adsorbed in amorphous clay-like material. Also shown are differences in SSA of the kaolinite/hematite/goethite samples from Mali and those from colloidal soils elsewhere. Results from this study can be integrated into a database of mineral dust properties, for applications in climate modeling, remote sensing, visibility, health (medical geology), ocean fertilization, and impact on equipment.

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Section: Discussionmentioning

confidence: 99%

Section: Simentioning

confidence: 99%

Section: Simentioning

confidence: 99%

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Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

et al. 2016

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“…Goethite has a characteristic large difference between the FC and ZFC LTSIRM data with much greater remanence acquired during the FC experiment as well as large decreases in remanence upon warming (Dekkers, ;Guyodo et al, ; Liu et al, ). Qualitative approximation of goethite abundance was performed using these experimental results (such as in Kars et al, ; Figure S19); however, several factors prevented us from performing absolute quantification. First, goethite has a large range of measured M s and M rs spanning an order of magnitude even at room temperature (Dekkers, ; Peters & Dekkers, ), which are much lower than other ferromagnetic phases making quantification in mixed phase natural samples difficult.…”

Section: Methodsmentioning

confidence: 99%

Unraveling the Mineralogical Complexity of Sediment Iron Speciation Using Sequential Extractions

Slotznick

Sperling

Tosca

et al. 2020

Geochem Geophys Geosyst

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Iron speciation is one of the most widely applied proxies used to reconstruct oxygen levels and redox conditions in past aqueous environments. The iron speciation proxy estimates proportions of different reactive iron species in fine‐grained sedimentary rocks, which are mapped to redox conditions based on empirical calibrations from modern sediments. It is based on a standardized extraction technique of sequentially applying acetate, hydroxlamine‐HCl, dithionite, and oxalate solutions to a powdered sample in order to dissolve iron phases and quantify the amount of iron carried by carbonates, “easily reducible” oxyhydroxides, ferric iron (oxyhydr)oxides, and magnetite, respectively. Although tested on pure minerals and mixtures, assessments of whether this sequential extraction process accurately dissolves the targeted minerals in natural sediments and sedimentary rocks are lacking. In our study, residues from each sequential extraction step were analyzed using rock magnetic and X‐ray diffraction experiments to identify and quantify the iron‐bearing minerals that were dissolved. The dithionite extraction robustly removes the targeted mineralogy as magnetic data show it to solubilize nearly all of the goethite. However, magnetic quantification of magnetite was orders of magnitude less than the iron measured in the oxalate extraction; X‐ray diffraction data suggest that dissolution of iron‐bearing clays, specifically berthierine/chamosite, could explain this disparity. Our data compilation shows higher values of iron from the oxalate extraction in Precambrian sedimentary rock samples, suggesting a significant temporal shift in iron cycling. Recognition of heterogeneity in chemical extraction efficiency and targeting is vital for holistic multiproxy interpretation of past oxygen levels and communication between disciplines.

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“…It cannot be excluded that a portion of the initially buried iron (oxyhydr)oxides have not been prone to sulphidisation during early diagenesis. Iron (oxyhydr)oxides have not yet been reported for Boom Clay, but nanocrystalline goethite has been identified in the reduced Callovian–Oxfordian clay formation of Bure, France (Kars et al, 2015). It is also possible that iron (oxyhydr)oxides have formed after burial upon the oxidation of pyrite.…”

Section: Resultsmentioning

confidence: 99%

First assessment of the pore water composition of Rupel Clay in the Netherlands and the characterisation of its reactive solids

Behrends

Veen

Hoving

et al. 2016

Netherlands Journal of Geosciences

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The Rupel Clay member in the Netherlands largely corresponds to the Boom Formation in Belgium, and this marine, clay-rich deposit is a potential candidate to host radioactive waste disposal facilities. Prediction of the speciation of radionuclides in Rupel Clay pore water and their retardation by interactions with Rupel Clay components requires knowledge about the composition of Rupel Clay pore water, the inventory of reactive solids and understanding of interactions between Rupel Clay and pore water. Here, we studied Rupel Clay material which was obtained from cores collected in the province of Zeeland, the Netherlands, and from drilling cuttings retrieved from a drilling in the province of Limburg, the Netherlands. Pore water was obtained by mechanical squeezing of Rupel Clay material from Zeeland. Additionally, anaerobic dilution experiments were performed in which the clay material was suspended with demineralised water or a 0.1 M NaHCO 3 solution. Solid-phase characterisation included determination of carbon, nitrogen and sulphur contents, measurement of cation exchange capacity (CEC) and sequential extraction of iron phases.In contrast to the pore water in Belgian Boom Clay, pore water collected from the location in Zeeland has a higher salinity, with chloride concentrations corresponding to 70-96% of those in seawater. The high chloride concentrations most likely result from the intrusion of ions from saline waters above the Rupel Clay in Zeeland. Cation exchange during salinisation might account for the observed deficit of marine cations (Na, K, Mg) and excess of Ca concentrations, in comparison with seawater. The measured CEC values at both locations in the Netherlands vary between 7 and 35 meq (100 g) −1 and are, for most samples, in the range reported for Boom Clay in Belgium (7-30 meq (100 g) −1 ).Pore water and solid-phase composition indicate that Rupel Clay from Zeeland has been affected by oxidation of pyrite or other Fe(II)-containing solids. When coupled to the dissolution of calcium carbonates, oxidation of pyrite can account for the elevated sulphate and calcium concentrations measured in some of the pore waters. The relatively low concentrations of pyrite, organic carbon and calcite in the Rupel Clay in Zeeland, in comparison to Limburg, might be an indicator for an oxidation event. Higher contents of dithionite-extractable Fe in Rupel Clay in Zeeland (0.7-2.6 mg Fe / g clay) than in Limburg (0.4-0.5 mg Fe / g clay) might also be a consequence of the oxidation of Fe(II) minerals. Oxidation in the past could have accompanied partial erosion of Rupel Clay in Zeeland before deposition of the Breda Formation. However, indications are given that oxidation occurred in some of the pore waters after sampling and that partial oxidation of the cores during storage cannot be excluded. Results from dilution experiments substantiate the influence of equilibration with calcium carbonates on pore water composition. Furthermore, removal of dissolved sulphate upon interaction with Rupel Clay has been...

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Identification of nanocrystalline goethite in reduced clay formations: Application to the Callovian-Oxfordian formation of Bure (France)

Cited by 14 publications

References 40 publications

Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

Unraveling the Mineralogical Complexity of Sediment Iron Speciation Using Sequential Extractions

First assessment of the pore water composition of Rupel Clay in the Netherlands and the characterisation of its reactive solids

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