Aleš Šoster

Karst landforms provide insights into landscape evolution and paleoclimate but are inherently challenging to date. An ancient interval of particularly intense weathering of Western Australian Pleistocene aeolianites is recorded in a spectacular pinnacle karst landscape with associated ferricrete nodules. (U-Th)/He dating of the ferricrete nodules revealed an age of 102.8 + 10.6/−11.4 thousand years, corresponding to marine isotope stage 5c. The (U-Th)/He age thus directly dates the wettest interglacial period in the region over the last 500 thousand years, which was responsible for the dissolution that formed the pinnacles. The reliability of the ferricrete (U-Th)/He age is supported by bounding optically stimulated luminescence and U-Th dates on associated aeolianites and carbonate precipitates, respectively. A (U-Th)/He approach is globally applicable to aeolianites with associated ferricretes, allowing more accurate dating of the environmental changes affecting these lithologies, and temporally constraining rapid Pleistocene climatic oscillations to better contextualize the associated evolution of the biosphere.

A quantitative analysis of the morphology, as well as an analysis of the distribution of components and surface/interfacial properties in poly(lactic acid)(PLA) InegoTM 3251D, poly(ε-caprolactone) (PCL) Capa 6800 and nano-silica (SiO2) Aerosil®200 blends, was conducted in this research. The study aimed to improve the understanding of how PLA, PCL, and nano-SiO2 interact, resulting in the specific morphology and surface properties of the blends. Samples were produced by varying the concentration of all three components. They were analyzed using SEM, EDS mapping, water contact angle measurements, surface free energy calculation, adhesion parameter measurements, and FTIR-ATR spectroscopy. The results showed that the addition of SiO2 nanoparticles led to an increase in the contact angle of water, making the surface more hydrophobic. SEM images of the blends showed that increasing the PCL content reduced the size of spherical PCL elements in the blends. FTIR-ATR analysis showed that SiO2 nanoparticles influenced the structure ordering of PLA in the blend with equal portions of PLA and PCL. In the samples with a higher PCL content, the spherical elements present in the samples with a higher PLA/PCL ratio have been reduced, indicating better interactions at the interface between PLA, PCL, and SiO2. SEM-EDS mapping of the PLA/PCL 100/0 blend surfaces revealed the presence of SiO2 clusters and the silicon (Si) concentration reaching up to ten times higher than the nominal concentration of SiO2. However, with the addition of 3% SiO2 to the blend containing PCL, the structure became more granular. Specifically, Si protrusions in the sample PLA/PCL 90/10 with 3% SiO2 displayed 29.25% of Si, and the sample PLA/PCL 70/30 with 3% SiO2 displayed an average of 10.61% of Si at the protrusion locations. The results confirmed the affinity of SiO2 to be encapsulated by PCL. A better understanding of the interactions between the materials in the presented blends and the quantitative analysis of their morphology could improve the understanding of their properties and allow the optimization of their application for different purposes.

The Carboniferous-Permian organic-rich shale in the Karavanke/Karawanken tunnel exhibits extensive pyrite mineralization in the form of veins and impregnations. Significant thermal alteration, induced by the overlying Mesozoic rock sequences, led to the decomposition of organic matter into methane, which subsequently acted as a sulfate-reducing agent. The primary source of sulfate were the evaporitic layers hosted within the Paleozoic strata. Reduced sulfur species necessary for pyrite formation were produced through methane-mediated thermochemical sulfate reduction, catalyzed by specific cations (Ni ²⁺ , Fe ²⁺ ) and clay minerals (montmorillonite). The mineralizing fluids originated from the expulsion of interstitial water and possibly from dehydration reactions related to the gypsum-to-anhydrite phase transition. The geochemical data indicate that the metals originated from the surrounding sedimentary rocks. These mineralizing fluids were characterized by low temperatures (< 300–350 °C), moderate reducing conditions, and low chlorinity. The low permeability of Carboniferous-Permian rocks, combined with the low trace element content of the investigated pyrite, mitigates the potential risk of environmental pollution.

Late Oligocene decapod crustaceans from the Trbovlje Formation of Slovenia, with a description of two new species of hymenosomatid crabs