research
My research interests include topics from biomedical mineralogy, genetic mineralogy, geochemical modelling, and mineral deposits exploration. The following list summarizes the research projects I am or was engaged in during my BSc., MSc., and PhD. studies respectively.
- Effect of grinding on minerals' capability to generate free radicals
- Geochemical modelling of the formation of hydrothermal Sb-Au mineralization in the Dubrava deposit, Nizke Tatry Mountains, Western Carpathians
- Carbonate-hosted Pb-Zn mineralization in the Maluzina – Olovienka deposit, Nizke Tatry Mountains, Western Carpathians
effect of grinding on minerals' capability to generate free radicals
Conducted at Stony Brook University, Geosciences Dept., USA (2004 – to date)
Advisor: Martin Schoonen
Collaborators: Corey Cohn
It has long been recognized that long-term exposure to air-borne particulate materials may lead to a number of serious chronic pulmonary diseases in humans, such as inflammations, pneumoconiosis (silicosis, the black lungs disease), or even lung cancer. It has been shown that inhalation of mineral dusts (e.g. quartz, asbestos) initiates free radical generation upon contact with lung tissues, process which activates macrophages (phagocytic cells) struggling to eliminate the pathogens. However, in the course of phagocytosis, more free radicals are produced by the cells themselves, while the pathogenic mineral particles often remain intact and capable of causing more havoc. This chain-like reaction eventually causes lung tissue fibrosis (scarring) with several adverse effects such as breathlessness, hyperventilation, and hypoxia.
Studies on this matter traditionally cover quartz, asbestos, coal, and few other materials, although based on the implicated mechanism it is apparent that this kind of mineral pathogenicity may be widespread among dozens of other minerals. Recent research by Cohn et al. (2004, 2005) suggests that pyrite, Fe-oxides, and other minerals are very capable in ROS generation when they are in contact with water.
Our research aims to examine how various factors, especially the mechanical treatment of mineral samples (crushing, milling, grinding), may affect the mineral-mediated ROS generation in water solutions. In this study, using several different techniques, we would like to investigate a greater variety of minerals and other materials than it was before by other researchers.
Besides the human health issues, our research is also relevant to the origin of life studies, as it provides important clues on how and whether the early complex organic molecules (prerequisites to abiogenesis) could have survived in mineral rich environments, typically envisaged as submarine hydrothermal vent environments in mid-ocean ridges.
geochemical modelling of the hydrothermal Sb-Au mineralization formation in the Dubrava deposit, Nizke Tatry Mountains
Conducted at Faculty of Sciences – Comenius University, Slovakia (2002 – 2004)
Advisor: Martin Chovan
Hydrothermal Sb-Au vein deposit in the vicinity of the Dubrava village in the Nízke Tatry Mts. has been exploited until 1992. In its time it was the greatest antimony ore producer in the former Czecho-Slovakia. An extensive genetically-oriented research was conducted in the last decade by a number of scientists (M. Chovan, V. Hurai, M. Orvosova, H. K. Sachan, J. Michalek and others).
The aim of this research was to model (by means of computer simulation) hydrothermal processes related to the deposition of vein minerals during the arsenopyrite-pyrite and the stibnite stage at the Dubrava deposit. The models should help to understand the deposit formation processes and decipher properties of the hydrothermal fluids (such as their chemical composition, pH, Eh, CO2 fugacity etc.) at the time of the ore deposition.
Our models suggest that the primary cause of mineral crystallization at the arsenopyrite-pyrite stage was cooling of hydrothermal fluids. Degassing of the fluids may have added to the mineral precipitation at this stage. Precipitation of the minerals due to chemical interactions between the fluids and the adjacent wall-rocks is improbable. According to our models, the system temperature at the beginning of mineral precipitation was likely as high as 390 °C and the CO2 fugacity may have reached 1 – 10 bar approximately.
The common occurrence of an arsenopyrite stage in Sb-Au mineralizations throughout the world suggests a common source of As and Sb, i. e. both metals enter these systems together within the same fluid. This presumption is supported by the results of our study; we have shown that hydrothermal fluids present in the system during arsenopyrite-pyrite stage could have been capable of bearing enough dissolved antimony for the later stibnite formation. In our models, stibnite started to precipitate only after the system temperature has considerably dropped down which is consistent with the fluid inclusion microthermometric data.
In our models we confirmed that precipitation of stibnite could have occured as a result of fluid mixing during the stibnite stage. The most important effect of the mixing was a rapid temperature decrease. The formation of vein minerals of the arsenopyrite-pyrite and stibnite stages was accompanied by wall-rock alterations. We approved that the rocks could have been chloritized under the arsenopyrite-stage conditions. Muscovite is a product of albite and chlorite decomposition at the temperatures below 300 °C. During the stibnite stage an intensive precipitation of smectites occurred in the rocks as a result of dissolving of albite, muscovite and chlorite. We presume that smectites were transformed to illite-smectites found in the deposit by later thermal degradation.
carbonate-hosted Pb-Zn mineralization in the Maluzina – Olovienka deposit, Nizke Tatry Mountains
Conducted at Faculty of Sciences – Comenius University, Slovakia (2000 – 2001)
Advisor: Martin Chovan
Collaborators: Alex Smirnov, Stefan Ferenc
Carbonate-hosted lead-zinc mineralizations are relatively uncommon in the Western Carpathians and typically there is a lot of uncertainty on their origins (they are usually considered to be epigenetic mineralizations formed during the Alpine orogenesis in the carbonaceous rock complexes of Triassic age). Very often it's unclear where the hydrothermal fluids have come from, as there are typically no magmatic rock bodies associated with the deposits. The mineralizations exhibit many characteristics of so-called Mississippi Valley Type syngenetic polymetallic mineralizations, however, the Western Carpathians deposits are rather classified as Alpine (or Bleiberg type) epigenetic deposits.
The Olovienka mineralization is a small outcrop of Pb-Zn ores within Anisian (Triassic) dolomites with no economic importance near the Maluzina village in the Nizke Tatry Mts. Areally small remains of old mining works in the area document a brief exploitation of the deposit during the Middle Ages, however, more detailed record of the mining activities is missing. Obviously, the deposit was soon claimed uneconomical and was abandoned.
With the aim to contribute to the dispute over the origins of this relatively unknown type of mineralization in the Western Carpathians, we explored the deposit using various methods: field work methods (mapping, sample collection), thin section and ore microscopy, EMPB, BSE, Pb isotope dating, UV light sample observation.