Quantitative X-Ray Diffraction Analysis of Clay-Bearing Rocks From Random Preparations

Środoń, Jan

doi:10.1346/ccmn.2001.0490604

Cited by 415 publications

(92 citation statements)

References 28 publications

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“…Mineral quantification was carried out on powdered samples spiked with 10% ZnO. This mixture was homogenized in McCrone mill with methanol, dried and side loaded into a holder for random orientation (43). XRD patterns were measured between 2-65°2-theta.…”

Section: Mineral Quantification and Clay Mineral Analysismentioning

confidence: 99%

Mineralogical constraints on the paleoenvironments of the Ediacaran Doushantuo Formation

Bristow

Kennedy

Derkowski

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

110

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Assemblages of clay minerals are routinely used as proxies for paleoclimatic change and paleoenvironmental conditions in Phanerozoic rocks. However, this tool is rarely applied in older sedimentary units. In this paper, the clay mineralogy of the Doushantuo Formation in South China is documented, providing constraints on depositional conditions of the Ediacaran Yangtze platform that host the earliest animal fossils in the geological record. In multiple sections from the Yangtze Gorges area, trioctahedral smectite (saponite) and its diagenetic products (mixed-layer chlorite/smectite, corrensite, and chlorite) are the dominant clays through the lower 80 m of the formation and constitute up to 30 wt% of the bulk rock. Saponite is interpreted as an in situ early diagenetic phase that formed in alkaline conditions (pH > 9). The absence of saponite in stratigraphically equivalent basin sections, 200 -400 km to the south, indicates that alkaline conditions were localized in a nonmarine basin near the Yangtze Gorges region. This interpretation is consistent with crustal abundances of redox-sensitive trace elements in saponitic mudstones deposited under anoxic conditions, as well as a 10‰ difference in the carbon isotope record between Yangtze Gorges and basin sections. Our findings suggest that nonmarine environments may have been hospitable for the fauna preserved in the Yangtze Gorges, which includes the oldest examples of animal embryo fossils and acanthomorphic acritarchs.clays ͉ saponite ͉ Neoproterozoic ͉ nonmarine ͉ early animals

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Section: Mineral Quantification and Clay Mineral Analysismentioning

confidence: 99%

Mineralogical constraints on the paleoenvironments of the Ediacaran Doushantuo Formation

Bristow

Kennedy

Derkowski

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

110

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“…The X-ray diffraction (XRD) analysis: a corundumspike sample was milled in methanol using a McCrone Micronising Mill (Retsch, Germany), then dried and side loaded to a XRD holder (Eberl et al 1996;Eberl 2003;Środoň et al 2001). The XRD analysis was carried out in the 4-65° 2Θ range using a Philips Xray diffractometer model 1710 (Almelo, the Netherlands) equipped with Cu tube and Ni filter at 20 mA and 40 kV.…”

Section: Methodsmentioning

confidence: 99%

The use of Snyder synthetic hydrograph for simulation of overland flow in small ungauged and gauged catchments

Fedorova¹,

Kovář²,

Gregar³

et al. 2018

Soil & Water Res.

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Vlček V., Pospíšilová L., Uhlík P. (2018) Variations in mineralogical and elemental composition of Turbic Cryosol (King George Island and James Ross Island), Skeletic Cryosol (J. Ross Island, the Trinity Peninsula), Leptic Andosols (Deception Island), and Skeletic Andosols (Deception Island) were studied. Significant differences in mineralogical composition in size fraction, vertical and horizontal position were determined by X-ray diffraction quantitative analysis. The differences were attributed to a variable degree of chemical weathering process. As a product of weathering were defined montmorillonite, chlorite, microcrystalline polymorphous silica, Fe oxides, and oxyhydroxides. Their content was increased towards the surface and in a finer fraction. Crystal thickness and size distribution of montmorillonite was measured by the Bertaut-Warren-Averbach technique and the results confirmed higher intensity of chemical weathering in Turbic Cryosols (J. Ross Island and King George Island). Feldspars and volcanic glass were the main phases found in soil samples from Deception Island. They were determined as phases of parent rock and indicated low intensity of chemical weathering. Clinoptilolite was identified in soil samples from J. Ross Island and Deception Islad and its hydrothermal origin was supposed. Soil (sample AP) from Base General Bernardo O'Higgins Riquelme had significantly higher content of phosphate minerals, which was a result of ornithogenic activities. Macro elements content was consistent with mineralogical analyses. Turbic Cryosols were rich in iron, aluminium, magnesium, and manganese (> 2%). Skeletic Cryosols contained also iron, aluminium, magnesium, manganese, calcium, and sulphur (> 1%). Leptic Andosols were rich in iron and aluminium (> 2%). Soil properties and humic substances quality were evaluted. Results of chemical and physical analyses indicated that poorly developed soils of Antarctica varied in acidity, conductivity, humus content, and texture. Humic substances content and quality were low. Mainly mechanical (physical) and chemical weathering processes played major role in the soil development accompanied by low intensity of biological activity.

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“…Samples were mixed with an internal standard, ZnO, and wet milled for 5 min using a McCrone micronizing mill. To obtain optimal random orientation of the crystallites, powders were side-loaded into alumina measurement holders (after Środoń et al, 2001;Snellings et al, 2010). XRD measurements were executed on a Phillips PW1830 diffractometer with Bragg-Brentano setup equipped with Cu-Kα radiation, a graphite monochromator and gas proportional detector.…”

Section: Methodsmentioning

confidence: 99%

Halloysite occurrence at the karstified contact of Oligocene sands and Cretaceous calcarenites in Hinnisdael quarries, Vechmaal (NE of Belgium)

Adriaens¹,

Ronchi²,

Mertens³

et al. 2017

Geol. Belg.

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ABSTRACT. In Belgium, numerous karstified sand-carbonate contacts are known for their association with halloysite precipitation. In the Hinnisdael caves of Vechmaal, eastern of Belgium, a similar geological setting is observed in dolines of karstified calcarenite of the Cretaceous Maastricht Formation filled with sand of the Oligocene St. Huibrechts-Hern Formation. At the sand-calcarenite interface, a discontinuous succession occurs of white clay and oxidized rust almost perfectly segregated. These lithologies are authigenic precipitations of high purity consisting of only halloysite-allophane and goethite-ferrihydrite respectively. The Al, Si and Fe necessary for this precipitation were derived from the short-range distance dissolution of glauconite and other silicate minerals present in the overlying sand unit. The mobilization of these ions was realized by the progressive oxidation of pyrite to jarosite leading to a significant acidification of the percolating water. It is furthermore observed that seemingly small variations in local conditions in the Curfs quarry of Valkenburg, the Netherlands, result in alunite, gibbsite, halloysite, allophane precipitation instead of jarosite, halloysite-allophane and goethite-ferrihydrite.

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Quantitative X-Ray Diffraction Analysis of Clay-Bearing Rocks From Random Preparations

Cited by 415 publications

References 28 publications

Mineralogical constraints on the paleoenvironments of the Ediacaran Doushantuo Formation

Mineralogical constraints on the paleoenvironments of the Ediacaran Doushantuo Formation

The use of Snyder synthetic hydrograph for simulation of overland flow in small ungauged and gauged catchments

Halloysite occurrence at the karstified contact of Oligocene sands and Cretaceous calcarenites in Hinnisdael quarries, Vechmaal (NE of Belgium)

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