Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

The characteristic of the granite grus in the northwestern part of the Jizerské hory Mts.: representative geological profiles and potassium distribution


Tomáš Štor, Karel Martínek

Geoscience Research Reports 46, 2013 (GRR for 2012), pages 168–172

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During geological mapping in the northwestern part of the Jizerské hory Mts. in 2009-2012 we recognized that weathering residues occur mainly on flat plateaus and gently inclined slopes up to 5°. Their thicknesses reach up to a few metres. We documented 26 sites in weathered granite layer of the Jizera and Liberec granite types. Based on data from airborne gamma-ray spectrometry we compared the concentrations of potassium in fresh rocks and their corresponding residuum layer. According to preliminary results, potassium in weathering residues is relatively depleted by 22.4 % and 7.1 % compared to unweathered rock in the Jizera and Liberec granites, respectively. In case field gamma-ray measurements will confirm this hypothesis, potassium depletion can be used as an indicator of eluvium for, e.g., geological mapping.