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Ostrava, Czech Republic

Jirasek J.,Institute geologickeho inzenyrstvi | Dolnicek Z.,Katedra geologie | Matysek D.,Institute cistych technologii tezby a uziti energetickych surovin | Skoda A.R.,Masaryk University
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2013

The barite mineralization at site Hrubá skála close to Pecka village (6 km E from the town Nová Paka) was known earlier from a short discovery report. It was re-examined by geological, mineralogical, and geochemical methods. Vein mineralization is developed in a significant tectonic zone hosted by mostly coarse-grained conglomerates to sedimentary breccias of the Brusnice Member (Westphalian D to Cantabrian, Pennsylvanian) of the Kumburk Formation, which is the basal unit of the Krkonoše Piedmont Basin. Barite is present as white crystalline masses or well-developed tabular crystals up to 6 × 4 cm in size, accompanied with minor quartz. Chemically it is pure barite with Sr content less than 0.003 apfu and Ca and Fe bellow 0.001 apfu. Cell parameters are a = 8.8861(1), b = 5.4561(7), c = 7.1584(9) Å. Barite contains aqueous all-liquid (L) or rarely L+V fluid inclusions with variable liquid-vapor ratios and variable salinity (3.5 - 16.5 wt. % NaCl eq.) containing NaCl. and CaCl2. The δ34S value of barie sample is +16.9 ‰ CDT. Both fluid inclusion and sulfur isotope data are comparable to those of monomineral post-Variscan barite veins of the Bohemian Massif. Locality Hrubá skála is probably one of the best available sites to study barite mineralization in the Late Paleozoic limnic basins in the Czech Republic. © 2013, National Museum Prague. All rights reserved.


Gabrhelova P.,Institute geologickeho inzenyrstvi | Osovsky M.,OKD as | Matysek D.,Institute cistych technologii tezby a uziti energetickych surovin | Sivek M.,Institute geologickeho inzenyrstvi | Jirasek A.J.,Institute geologickeho inzenyrstvi
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2014

Siderite concretion horizons are known both from the paralic and terrestrial sediments of the Upper Silesian Basin.Significant horizon above the No. 22 Coal Seam in the Upper Suchá Member of Karviná Fm. (Westphalian, Pennsylvanian)was investigated by geological, mineralogical and geochemical methods. Horizon is developed virtually in thewhole area of the Upper Suchá Member, where geological documentation is available. It is hosted by grey claystonesin the direct roof of the No. 22 Seam, which belongs to the freshwater Faunistic Horizon Group Hubert. Shape of theconcretions is mostly ellipsoidal and lensoidal, tabular ones are also present. Their size usually ranges between X0cm and 1 m. Concretions do not have internal layering, warping of the claystone layering around them was observed.Typical feature of concretions is presence of septarian cracks. Matrix of the concretions is formed almost purely bytwo populations of non-zoned Mg-Ca or Mg-rich siderite with dispersed quartz, mica and accessory minerals similar tosurrounding claystones, i.e. apatite, zircon, monazite and TiO2 minerals. Septarian fissures are filled by two generationsof carbonate with predominant dolomitic composition and beef (fibrous) structure. Older one has dark brown colour,younger is white. Younger dolomite shows weak oscillatory zoning in BSE image caused by distribution of Fe-ions.Youngest fissure minerals are Mg-rich siderite, ankerite, calcite, quartz, baryte, apatite, halite, dickite and mineral fromthe chlorite group. Common sulphide minerals as pyrite, marcassite, chalcopyrite, sphalerite, galena, millerite and siegeniteare also present, together with mineral phases from the vaesite-cattierite-pyrite series. The δ13C value of matrixsiderite is +0.77 ‰ PDB and that of septarian dolomite -8.15 ‰ PDB, the δ18O value of matrix siderite is -11.25 ‰ PDBand that of septarian dolomite -9.79 ‰ PDB. Siderite matrix data shows fractionation during diagenetic processes,while fissure carbonate represents post-sedimentary hydrothermal product. Dolomite isotope data are comparable tothose of hydrothermal carbonate mineralization of Early Carboniferous of the Nízký Jeseník Mts. We interpret concretionhorizon as sediment of internal part of large-scale freshwater lake. Concretions are very probably syncompactionaland develop by pervasive growth mechanism. © National Museum Prague. All rights reserved.


Belis S.,a.s. Dul Karvina zavod CSA | Osovsky M.,a.s. Dul Karvina zavod CSA | Matysek D.,Institute cistych technologii tezby a uziti energetickych surovin | Sivek M.,Institute geologickeho inzenyrstvi | Jirasek J.,Institute geologickeho inzenyrstvi
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2015

The paper presents results of a research on the only coal tonstein known from the Saddle Member of the Karviná Formation in the Czech part of the Upper Silesian Basin. It is a tonstein in the Coal No. 560, which was first mentioned in 1966. It forms a thin layer, mostly <1 cm, situated 15 cm below the roof of the coal. Twenty one distinct occurences were described previously and twenty five new ones were recognized by this study. According to a classification it belongs to a group of crystal tonsteins, because its substantial part consists of aggregates of authigenic kaolinite. Minerals present in the tonstein are mostly kaolinite (cca 71 %), quartz (cca 8 %), mineral of the chlorite group (cca 6 %), sanidine (cca 6 %), muscovite (cca 6 %), and anatase (cca 3 %). Accessory minerals can be grouped into several categories. Primary magmatic ones are apatite and zircon. Those connected with low-temperature hydrothermal fluids are galena, chalcopyrite, and pyrite. Influenece of hypersaline brines resulted in presence of Sr-rich anglesite, and celestine. Baryte formation could be connected to both above-mentioned processes. Jarosite originates from weathering of pyrite. Uncertain is a position of REE±Al phosphates, possibly minerals of the monazite, rhabdophane, and florencite groups. Their source material is possibly of volcanic origin, but it was affected by diagenetic processes. The tonstein of the Coal 560 is an important correlation marker and has a potential for radio-isotopic dating. © 2015, National Museum Prague. All rights reserved.


Jirasek J.,Institute geologickeho inzenyrstvi | Matysek D.,Institute cistych technologii tezby a uziti energetickych surovin | Vaculikova L.,Oddeleni Laboratorniho Vyzkumu Geomaterialu | Sivek M.,Institute geologickeho inzenyrstvi
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2015

At historical iron ore mining site near Poniklá, famous for natrodufrénite occurence, were described two minerals from the coronadite group (hollandite supergroup) - hollandite and cryptomelane. They are present in cavities and fissures of brecciated iron ore with quartz. Both form of greyish-black to black reniform aggregates with dull to submetallic lustre several milimeters thick, covering the areas mostly up to 10 cm2. Submicroscopic layers of hollandite are alternating with the same of cryptomelane. Occurence of minerals from coronadite group was confirmed by the powder XRD, as well as by IRS. Chemical data from EMPA-WDS confirmed presence of both phases with composition close to its end-members, with minor admixture of Ca2+, Sr2+ a Fe3+, in case of hollandite also K+. We believe that these minerals were originally described as psilomelane and pyrolusite in 19th century from the Poniklá. Co-existence of iron and manganese oxidic minerals well corresponds to iron-rich residual deposits, where both elements remain fixed in relatively stable minerals and their mobility remains unimportant even during lateritic weathering and carst formation. © 2015, National Museum Prague. All rights reserved.


Majzlan J.,Friedrich - Schiller University of Jena | Stevko M.,Katedra mineralogie a petrologie | Chovan M.,Institute geologickeho inzenyrstvi
Bulletin Mineralogicko-Petrologickeho Oddeleni Narodniho Muzea v Praze | Year: 2015

In this contribution, we studied mineralogy of a small, long abandoned ore occurrence near the village of Hiadeľ in the Nízke Tatry Mts. (Slovakia). An earlier mineral association consists of pyrite I, arsenopyrite, rutile, apatite, monazite, and possibly zircon. This association is located in alteration zones with abundant sheet silicates. Carbonates are found in this association but also in the milky quartz that contains no sheet silicates. The composition of the carbonates is variable; they belong to the siderite-magnesite and dolomite-ankerite solid solution, rarely to calcite. Later ore minerals are represented by stibnite, Pb-Sb sulfosalts (zinkenite, jamesonite, or robinsonite), tetrahedrite, chalcostibite, bournonite, and pyrite II. The temporal relationship among these minerals cannot be determined from our samples. Tetrahedrite is Zn-rich and Ag-poor. From a mineralogical point of view, this occurrence does not deviate from other ore deposits and occurrences known in the Tatric part of the Nízke Tatry Mts. © 2015, National Museum Prague. All rights reserved.

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