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Speleothems in sandstone crevice and boulder caves of the Elbe River Canyon, Czech Republic
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SYSNO ASEP 0561806 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Speleothems in sandstone crevice and boulder caves of the Elbe River Canyon, Czech Republic Author(s) Adamovič, Jiří (GLU-S) RID, SAI, ORCID
Kukla, J. (CZ)
Filippi, Michal (GLU-S) RID, SAI, ORCID
Skála, Roman (GLU-S) RID, SAI, ORCID
Mészárosová, Noemi (GLU-S) ORCID, RID, SAISource Title International Journal of Speleology. - : Societa Speleologica Italiana - ISSN 0392-6672
Roč. 51, č. 2 (2022), s. 141-162Number of pages 22 s. Publication form Print - P Language eng - English Country IT - Italy Keywords speleothems ; silica ; coralloids ; sandstone caves ; Elbe sandstones OECD category Mineralogy R&D Projects GA19-14082S GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support GLU-S - RVO:67985831 UT WOS 000862894800001 EID SCOPUS 85138508434 DOI 10.5038/1827-806X.51.2.2427 Annotation A variety of speleothems are present in crevice and boulder caves developed in Cretaceous sandstones of the Elbe River canyon in northern Czech Republic. A set of complementary instrumental mineralogical methods was applied to characterize the speleothems and cave dripwaters, including X-ray powder diffraction, scanning electron microscopy and microanalysis, Raman spectroscopy and optical emission spectrometry. Four morphological types were distinguished and characterized in terms of their mineral and chemical composition: 1, rusty brown mud-dominated coatings with micro-gours, composed of a mixture of clay minerals, 2, white “chalky” coatings (moonmilk) composed of calcite with minor gypsum, 3, cauliflower-shaped coralloids composed of calcite and silica in a layered structure, with gypsum layers in apical parts, 4, knob coralloids, dark gray-brown with smooth surfaces and distinctly layered structures, composed of silica (quartz, opal-A) and Si–Al phases (kaolinite) and including phosphate-rich laminae (sasaite, vashegyite, taranakite). Only modest microbial mediation of silica precipitation was observed in cauliflower-shaped coralloids while no clear signs are present in knob coralloids despite organic enrichment in the topmost layer. White “chalky” coatings and cauliflower-shaped coralloids precipitated from weakly acidic Ca-, Mgand sulphate-rich deeper sandstone percolates. These forms are probably still active, much like the micro-gours, produced by particulate clay deposition. Formation of knob coralloids combined clay deposition and the dominant silica precipitation from pore waters similar to the present shallow acidic percolates under changing climatic conditions, probably in the Pleistocene. It was favored by specific rock lithology (quartzose sandstone with kaolinite admixture), which explains the scarcity of similar forms in sandstone caves. Concentration of knob coralloids along protruding vertical edges and the presence of wind-guided forms suggests that silica precipitation was driven by evaporation under a constant air flow. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2023 Electronic address https://digitalcommons.usf.edu/ijs/vol51/iss2/6/
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