Uher P.,Katedra mineralogie a petrologie |
Ferenc S.,Katedra geografie |
Spisiak J.,Katedra geografie
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2013
Unique chromian-nickeloan muscovite occurs in magnesite-dolomite-quartz listvenite rock (carbonatized and silicified serpentinite) from Muránska Zdychava near Revúca (Veporic Superunit, Slovenské rudohorie Mts., central Slovakia). Muscovite forms anhedral aggregates and veinlets in quartz and carbonate groundmass, up to 20 μm across. It shows emerald-green colour, electron-microprobe analyses revealed 9.5 to 12 wt. % Cr2O3 (0.52 - 0.67 apfu) and 2.1 to 4.5 wt. % NiO (0.11 - 0.25 apfu). The average crystallochemical formula of the Cr,Ni-rich muscovite is close to K0.65(Al1.13Cr0.59Ni0.19Mg0.16Fe0.05)Σ2.12(Si3.33A l0.67)Σ4.00(OH)1.90F0.10. The Ni contents belong to the highest concentrations of this element ever obtained on a mineral of mica group. The Cr-Ni muscovite is associated with accessory chromite, pyrite, and Ni-sulphide minerals (pentlandite, violarite, ullmannite and millerite). The Cr,Ni-rich muscovite and associated minerals of listvenite originated by hydrothermal-metasomatic overprint on primary, Lower Paleozoic metaultrabasic rocks during Alpine (Cretaceous) orogenesis.
Bonova K.,Ustav Geografie |
Bella P.,Katedra Geografie |
Kovacik M.,Statny Geologicky Ustav D. Stura RC Kosice |
Bona J.,Kpt. Jarosa 13 |
And 3 more authors.
Acta Geologica Slovaca | Year: 2014
A combination of sedimentological and mineralogical methods with emphasis on heavy mineral assemblage research applied to allochthonous sediments in the Liskovská jaskyňa Cave located in the western part of the Liptovská kotlina Basin (in the tectonic horst composed of Triassic limestones at foothills of the Chočské vrchy Mts.) were used for the identification their provenance and sedimentary history. Allochthonous fine-grained sediments were studied in three profiles (LI-1 to LI-3). The sediments originated mostly from the suspension in slow water flow to stagnant water (slackwater facies). This material could be later redeposited during the younger flooding event and small-scale slumps and gravity flows (mudflows) have been locally generated on steeper cave floors. Based on mineralogical study the cave sediments are composed of quartz, muscovite, calcite, chlorite, K-feldspar, plagioclase and dolomite. A heavy mineral assemblage is formed by garnet, zircon, apatite, monazite, tourmaline, staurolite, amphibole, rutile, titanite, epidote, sillimanite, allanite, andalusite, pyroxene and xenotime. Opaque minerals are represented by ilmenite, pyrite, magnetite, Cr-spinel, hematite, Cu-sulfides and Fe-oxyhydroxides. Their mineralogical character indicates the heterogenous source material which was transported by the Váh River. The results are significant for a more accurate reconstruction of origin and development of the cave, mainly its sedimentary phases in Middle and Late Pleistocene related to floods from the adjacent river bed.
Preis J.,Katedra Geografie
Epidemiologie, Mikrobiologie, Imunologie | Year: 2010
The article discusses selected papers of foreign geographers who seek correlation between biomedical characteristics of the HIV/AIDS pandemic in various parts of the world and socioeconomic factors that either fuel or prevent the spread of infection. It also points out the benefit from the interconnection between medical sciences, epidemiology and geography and outlines the research areas in which the Czech Republic could participate in the future.
Papco P.,Katedra geografie
Geograficky Casopis | Year: 2011
The paper deals with the occurrence of gully erosion over time in a selected area in the northern part of the Nitrianska pahorkatina Hill Land. The study was based on an analysis of maps and the correlative sediments relating to the evolution of the selected permanent gully. Historical maps from 1783, 1838, 1882 and current topographic maps were evaluated for this purpose. The analysis of correlative sediments consisted of identification and dating of the relevant components within the colluvial fan sediments and the material deposited in the mouth of the gully. Radiocarbon 14C dating of an organic material and expert age estimation of archaeological artefacts were used to determine the relative age of the layers. On the basis of achieved results occurrence of accelerated gully erosion that probably took place in the 14th century and the 19th to 20th century was detected.
Gajdos A.,Katedra Geografie |
Klauco M.,Katedra Geografie |
Skodova M.,Katedra Geografie
Geograficky Casopis | Year: 2012
The paper deals with the determination of the ecological significance of the forest ecotone vegetation in the semi-natural landscape of the Starohorské Hills. For this purpose, the quantitative metrics of landscape structure in the investigated area is interpreted, with emphasis on the forest ecotone vegetation. The quantity (number, size, density, size variation) and spatial character (layout, orientation and shape) of the landscape patches is examined. The impact assessment on forest ecotone species diversity of vegetation was included in. We assign the first degree of ecological significance for the forest ecotones vegetation according to the ecological carrying capacity methodology by Hrnčiarová et al. (1997). © Institute of Geography SAS.