The Ložnica stream originates in the small settlement of Kot na Pohorju, which is geologically located in the area of Pohorje granodiorites. It flows through lithologies of gneisses and glisters and continues downstream through recent sediments. In the immediate vicinity east of the stream, there is the Slovenskobistriški ultramafic complex (SBUC), which consists of serpentinites with amphibolite and eclogite lenses. The Ložnica stream is therefore a potential deposit of heavy sands. Sediment samples were collected at three sampling points along the route and identified granulometrically, petrologically and geochemically. The magnetic fraction was separated from the non-magnetic one.
Data were obtained using SEM-EDS (scanning electron microscopy - energy dispersive spectroscopy) and ICP-MS (inductively coupled plasma mass spectrometry). By granulometric analysis, we proved that the minerals of the sample sites differ from each other due to the distance from the source rock and lithology. Downstream, the grain size decreases and minerals get sorted. The sediment was also subjected to moderate recycling and weathering.
As expected, we observed the presence of heavy minerals, dominated by garnets with a terminal pyrope link and the mineral ilmenite. Downstream, in the third sample site, we detected an instantaneous enrichment of chromium with chlorite secretions that underwent the serpentinization process characteristic of Slovenska Bistrica utramafic complex (SBUC). Based on the geochemical analysis of the sediment, garnets and monazites, we found that the sediment of the Ložnica stream originates from nearby metamorphic rocks of gneiss, glistening and SBUC rocks, while Pohorje granodiorite shows no effect. We also found rare earth elements (REE) and Ti, which from 2020 belong to the list of critical elements.
The enrichment factor (EF) showed smaller enrichments of the elements, which means that their content does not meet the condition of economic exploitation.
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