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Palygorskite from cave sediments: case study from Wadi Haqil, United Arab Emirates
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SYSNO ASEP 0473049 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Palygorskite from cave sediments: case study from Wadi Haqil, United Arab Emirates Tvůrce(i) Zupan Hajna, N. (SI)
Skála, Roman (GLU-S) RID, SAI, ORCID
Al-Farraj, A. (AE)
Šťastný, Martin (GLU-S) RID, SAI
Bosák, Pavel (GLU-S) RID, SAIČíslo článku 689 Zdroj.dok. Arabian Journal of Geosciences. - : Springer - ISSN 1866-7511
Roč. 9, č. 17 (2016)Poč.str. 11 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. DE - Německo Klíč. slova palygorskite ; gypsum ; cave sediments ; X-ray powder diffraction ; scanning electron microscopy ; Ras Al-Khaimah Emirate Vědní obor RIV DB - Geologie a mineralogie Institucionální podpora GLU-S - RVO:67985831 UT WOS 000387152300007 EID SCOPUS 84994036026 DOI 10.1007/s12517-016-2721-2 Anotace The x-ray powder diffraction identification of clay minerals both in bulk samples and in separated clay fraction confirmed the presence of palygorskite in samples of cave sediments from Wadi Haqil (the western slopes of Musandam Mountains; Ras Al-Khaimah Emirate, UAE). Samples contain quartz, gypsum, smectite, kaolinite, calcite, and palygorskite, some of them chlorite, illite, feldspars, and goethite. Calcite dominates in most samples; smectite prevails in clay fraction. After heating, the 001 reflection of chlorite shifts to higher diffraction angles and its intensity decreases; these features indicate that the chlorite represent a Fedominant species. Unit-cell dimensions of major phases as refined by the Rietveld method are in agreement with literature data. Chemical composition of palygorskite was derived from unit-cell dimensions as follows: MgO content is 1114 wt% and Al2O3 10-13 wt%. Clay mineralogy is only hard to ascertain from the scanning electron microscope (SEM) images even after being combined with the energy-dispersive spectrometer data. The SEM was also used to characterize gypsum grains; they often display flow deformation features. Studied cave sediments represent palygorskite-bearing weathering products and desert soils re-deposited from the cave surroundings by slope processes and wind and/or surface runoff. The mixture with other clay minerals, quartz, feldspars, etc. supports this interpretation. Fine-grained quartz fraction is probably wind-blown. Gypsum and calcite are the precipitates (crusts and/or cements), although gypsum can also be re-deposited from omnipresent gypsum-cemented surface sediments. Pracoviště Geologický ústav Kontakt Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Rok sběru 2017
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