Natural SciencesEarth SciencesGeologyGeochemistryGeomagnetismSedimentologyMineral GeochemistryRock MagnetismSediment CompositionSedimentary GeochemistryAbundance ChangesAeolian DepositionGamma-ray SpectrometryGeological Sample AnalysisImpuritiesMagnetic MineralsMagnetic Susceptibility LoggingMineral Magnetic Properties
This paper deals with the variations in non-carbonate impurities trapped in the Lower Devonian limestone beds in the Prague Synform.Different assemblages are encountered for the Lochkovian, lower Emsian and Pragian. The Lochkovian is characterized by pyrite–pyrrhotite assemblages with lower abundance of iron oxides-oxyhydroxides,the Pragian shows relatively abundant iron oxides-oxyhydroxides.Major changes in magnetic susceptibility (MS) and gamma-ray spectrometric logs also coincide with the Lochkovian/Pragian boundary. Maximum values of MS and relatively high Th, K concentrations above the boundary correspond to the elevated amounts of barite and Ba concentrations.This level is interpreted as a significant interval with elevated delivery of impurities of aeolian origin, deceleration of sedimentation rate together with decreased carbonate productivity.REE distributions are indicative of the aeolian origin of trapped impurities.