Mineralogical and chemical characteristics of black coatings in Postojna cave system

Mineralogical and chemical analyses of black coatings from two sites in Postojna cave system were studied. Scattered samples were taken from the entrance parts of the cave and from Črna Jama. Thin sections, powder X-ray diffraction (XRD) technique and scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM/EDS) were used. Microscopic investigation of thin sections of black coloured material from both locations revealed that the main material is carbonate – calcite, with evenly dispersed prevailingly minute opaque black grains. The XRD analysis on samples from both locations confirmed just a presence of calcite with minor quartz and dolomite, excluding Mn and Fe oxides or apatite-group minerals as reason for black colouring. The SEM/EDS analysis of samples from the entrance parts of Postojna cave system was consistent with XRD analysis, which did not show any Mn oxides. The high content of C measured in the black coatings from the cave entrance parts indicates organic C, which deposited on the cave walls at time of the petrol explosion during WW2. We can attribute black coatings from Črna Jama to one form of organic C as well, but it is certainly different from the one in the entrance parts of Postojna cave system. As in Črna Jama no other evidence indicates for old human inhabitation of the place: torches of first tourists are a more probable origin of charcoal. On both locations black coatings can be at least partly described by microclimate conditions at cave entrances, which caused the deposition of organic material of allogenic origin (for example soot due to the forest fires)

Provenance of the Early Bronze Age Greenstone Axes from Monkodonja

U članku su prikazana tri ulomka kamenih sjekira s gradine Monkodonja, za koje je obavljena petrografska analiza. Prikazani su načini analize i dobiveni rezultati o vrsti i porijeklu kamena. Sirovine za njihovu izradu - žad, serpentinit i metadijabaz - potječu iz različitih izvora. Ti su materijali najčešće u uporabi kroz mlađi neolitik i eneolitik, a na Monkodonji je njihovo korištenje datirano još barem kroz prvu polovicu 2. tisućljeća pr. n. e.This article covers three fragments of stone axes from the hillfort of Monkodonja, for which a petrographical analysis was performed. Shown here are the methods employed for this analysis and the obtained results regarding the types and origins of stone. The raw materials used for their manufacture, jade, serpentinite and meta-diabase, stem from different sources. Most often these materials were in use throughout the Late Neolithic and Eneolithic, and in the case of Monkodonja, their use was also dated at least through the first half of the 2nd millennium BC

The level of air pollution in the impact zone of coal-fired power plant (Karaganda City) using the data of geochemical snow survey (Republic of Kazakhstan)

Coal-fired power plants emissions impact the air quality and human health. Of great significance is assessment of solid airborne particles emissions from those plants and distance of their transportation. The article presents the results of air pollution assessment in the zone of coal-fired power plant (Karaganda City) using snow survey. Based on the mass of solid airborne particles deposited in snow, time of their deposition on snow at the distance from 0.5 to 4.5 km a value of dust load has been determined. It is stated that very high level of pollution is observed at the distance from 0.5 to 1 km. there is a trend in decrease of dust burden value with the distance from the stacks of coal-fired power plant that may be conditioned by the particle size and washing out smaller ash particles by ice pellets forming at freezing water vapour in stacks of the coal-fired power plant. Study in composition of solid airborne particles deposited in snow has shown that they mainly contain particulates of underburnt coal, Al-Si- rich spheres, Fe-rich spheres, and coal dust. The content of the particles in samples decreases with the distance from the stacks of the coal-fired power plant

SEM/EDS characterisation of dusty deposits in precipitation and assessment of their origin

Detailed scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis of dusty material in rainfall residue, deposited and collected on February 19th 2014 in Ljubljana, was carried out with the intention to characterise it according to its chemical and mineral composition and to assess its origin. The material consists of poorly sorted and sharp-edged particles of mostly very fine-grained silt and clay fractions, which is consistent with long-range aerial transport. Particles are represented by illite, chlorite and kaolinite group clay minerals, quartz, feldspars, carbonates, accessory minerals and secondary Fe-oxy-hydroxide minerals. Quantities of minerals and illite/ kaolinite ratio (4.5) correspond to dusts in rainfall residues originating from Moroccan Atlas, while chlorite/kaolinite ratio (2.8) agrees better with dust from central Libya. The element ratios Al/Si, Ca/Al, K/Ca, Mg/Al, Fe/Al and (Ca+Mg)/Fe in the studied dusty deposit are in good agreement with ratios in dusts from rainfall residues originating from Morocco and northern Mauritania. This was also confirmed by the trajectories of cloud movement that caused precipitation with dusty deposit, although the back trajectory HYSPLIT simulation of air masses indicated northern Mauritania, central Niger, southern Algeria, southwestern and central Libya as the most possible source regions

The environmental impact of historical Pb-Zn mining waste deposits in Slovenia

Mining waste deposits (MWDs) represent significant and constant pollution source for the environment worldwide, thus it is very important to identify and diminish their environmental impacts. The aim of this study was to determine long-term environmental impacts and their temporal variations of MWDs in Pb–Zn mining districts in Slovenia and assess stability of potentially harmful element (PHE)-bearing phases in stream water. The results showed that investigated MWDs are important source of PHEs in stream sediments and that PHEs mostly occur as fine-grained and liberated PHE-bearing ore minerals. MWDs have generally stronger impact on sediments of smaller streams draining MWDs and main streams close to their confluences, however, fine-grained PHE-bearing material is transported along major watercourses over long distances causing regional pollution. Main ore minerals are mostly soluble in stream water. However, measured PHE leaching potential of MWDs is negligible. PHE levels in stream waters are thus low, demonstrating that drainage of MWDs predominantly contributes to PHE pollution in solid particulate form. Possible long-term remediation solution that would reduce environmental impact is recovery of metals from fine grain size fractions of MWDs, which could become an effective practice in sustainable management of historical MWDs. However, further studies of MWDs’ secondary resource potential, processing technology and evaluation of environmental aspects of extraction are needed

Characterisation of presumed meteorite from Trbovlje

The main objective of this study was to identify and characterise a specimen of presumed meteorite, supposedly found in 1947 while crushing gangue material from an open-pit coal mining site in Trbovlje. The presumed meteorite was characterised according to its physical properties, chemical and mineral composition using EDSanalysis. Based on macroscopic characteristics and physical properties, such as external features, magnetism and density, and reaction with diluted HCl, it was established that the specimen is not a meteorite but a concretion that contains calcite. SEM/EDS analysis showed that the studied material was compositionally homogeneous. It consists predominantly of calcite, gypsum and iron sulphide. The prevailing mineral is calcite, which forms irregular grains.Iron sulphide occurs as pyrite (or marcasite), which forms thin coatings rimming calcite grains, while gypsum formsthin transitional layers between calcite grains and pyrite or marcasite crusts as a result of reaction between ironsulphide oxidation products and calcite. The matrix between grains mostly consists of very fine-grained mixture of iron sulphide, calcite, gypsum and iron sulphide oxidation products, however, fields of pure gypsum were also found between some grains. According to the composition of the concretion, it can be assumed that the specimen isa pyrite- and/or marcasite- carbonate concretion, perhaps coal ball, which most probably formed by mineralisation within peat in the early stage of coal genesis in the Trbovlje formation

Triassic and Jurassic beds in Krim Mountain area (Slovenia)

The Krim Mountain and its surroundings are characterized by Upper Triassic to Middle Jurassic rocks, which were deposited on the northern margin of the Dinaric Carbonate Platform. Upper Triassic beds are represented by Main dolomite that exhibits supra- to subtidal Lofer facies. The uppermost Triassic is characterized by approximately 40 m thick horizon of dolomitic breccia. Upper Triassic beds pass gradually into Lower Liassic dolomitic breccia, coarse-grained dolomite and micritic limestone. Presence of dolomitic breccias and absence of supra-intertidal sedimentary structures indicate sea-level rise. Middle Liassic beds consist of oolitic-oncolitic and lithiotid limestones deposited in alternating restricted lagoonal and open shallow-water environment. Upper Liassic beds are characterized by oolitic-oncolitic limestones, bituminous dolomitized limestones and dolomitic breccia deposited in high-energy shallow-water environment. Middle Jurassic beds consist of oolitic, oolitic-oncolitic and micritic limestones, formed predominantly in high-energy subtidal environment

Two years of the Javorje meteorite investigations

Meteorite Javorje is a IIIAB medium octahedrite iron meteorite with 7.83 wt% Ni content. It was found inNovember 2009 near village Javorje in the Poljane Valley. With nearly five kilograms it represents the largest andheaviest meteorite found so far in the territory of Slovenia. The purpose of this paper is to present general characteristicsof meteorite Javorje to the slovenian geological community. This paper reviews results of already publishedresearch of this meteorite and provides some newer findings and details about major, accessory and secondaryminerals, and also its cooling rate

Application of SEM/EDS to environmental geochemistry of heavy metals

Heavy metals represent a ubiquitous constituent of the near-surface environment, present in widely varyingconcentrations that typically have little impact on human behaviour and health. However, the mining of metals anduse of these metals in industrial processes has produced significant anthropogenic inputs of metals to both localand global environments. As such, a rigorous overview of the current accumulation of heavy metals and knowledgeof mineralogy of heavy metal-bearing phases is important for understanding their stability, solubility, mobility,bioavailability and toxicity. These data are of fundamental importance for environmental risk assessment and evaluationof future scenarios. Since conventional geochemical analyses provide limited information, other analyticalmethods have to be utilized for the characterisation of heavy metal-bearing phases. Significant analytical methodfor identification and characterisation of heavy metals in environmental media is a scanning electron microscopecoupled with energy dispersive X-ray spectrometer (SEM/EDS), an apparatus for qualitative and semi-quantitative chemical analysis at microne level, newly introduced to Geological Survey of Slovenia. Use of SEM/EDS was already introduced to environmental studies world-wide. In Slovenia, SEM/EDS analyses of environmental media werefirstly carried out on the Meža River stream sediments and snow deposits from Ljubljana urban area.Heavy metal-bearing phases in the Meža River stream sediments were apportioned to three source areas: Mežica mining/smelting area (geogenic-technogenic origin), Ravne ironworks area (technogenic origin) and the Meža River catchment area (geogenic origin), which corresponds to data obtained by conventional geochemical and multivariate statistical methods. Airborne particles, identified in urban snow deposits, were interpreted as geogenic particles, represented by fragments of heavy metal-bearing minerals, and technogenic particles that originate from combustion of solid and liquid fuels, iron and steel melting processes and road traffic emissions.SEM/EDS proved to be a very useful analytical method for the study of heavy metal-bearing phases and characterisation according to their sources and genesis