Paper No. 135-9
Presentation Time: 4:10 PM
WEATHERING OF GLAUCONITE IN SOILS OF TEMPERATE CLIMATE
SKONECZNA, Magdalena1, SKIBA, Michal1, SZYMANSKI, Wojciech2, MAJ-SZELIGA, Katarzyna1, KISIEL, Marta1 and BLACHOWSKI, Artur3, (1)Institute of Geological Sciences, Department of Mineralogy, Petrology and Geochemistry, Jagiellonian University, Gronostajowa 3A, Krakow, 30-387, Poland, (2)Institute of Geography and Spatial Management, Department of Pedology and Soil Geography, Jagiellonian University, Gronostajowa 7, Krakow, 30-387, Poland, (3)Institute of Physics, Mossbauer Spectroscopy Laboratory, Pedagogical University, Podchorazych 2, Krakow, 30-084, Poland
The aim of the present research was to investigate the processes of glauconite weathering in soils of temperate climate. Five soil profiles from eastern Poland, each developed on glauconite-bearing sediments of Oligocene to Miocene age, were sampled. Basic physical and chemical properties of bulk soil samples (<2 mm) were analyzed, such as color, texture, pH, carbonates and soil organic carbon contents. Clay fractions (<2 µm and <0.2 µm) were separated using centrifuge after application of Na-acetate buffer treatment to remove carbonates and divalent exchangeable cations. Obtained clays were analyzed using X-ray diffractometry (XRD) and Fourier-transform infrared spectroscopy. Glauconite pellets were separated magnetically and analyzed using XRD. Selected clays and pellets were also analyzed using Mössbauer spectroscopy and energy-dispersive spectroscopy. Thin sections were prepared from undisturbed soil material from selected horizons, and observed under optical microscope.
The pH conditions of the studied soils varied from 4.3 to 8.6. Three of the soils were acidic and two of them were alkaline. Chemical composition of parent glauconite pellets did not vary significantly between the profiles; however, Fe(II) constituted from 4% to 13% of total Fe in primary glauconite. Glauconite weathering products were observed mostly in clay fractions, which contained, except for glauconite, also rich in smectite glauconite-smectite mixed layered minerals, kaolinite, and goethite or lepidocrocite. At least in three cases the weathering products were also present in the pellets. They were glauconite-smectite, kaolinite, goethite and/or lepidocrocite. Fe-oxy/hydroxides likely occurred also in XRD-amorphous phases (nano-phases). No major differences in the weathering effects were observed between soils having different pH conditions. Content of Fe(II) in primary glauconite did not seem to influence the weathering processes either.
Acknowledgements:
This study was financed by the National Science Centre, Poland [grant number: UMO-2016/23/B/ST10/02000]
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