scholarly journals Fosfohedyfán z opuštěného železnorudného ložiska Hraničná (Slezsko, Česká republika)

2020 ◽  
Vol 28 (1) ◽  
pp. 44-47
Author(s):  
Jakub Jirásek ◽  
Dalibor Matýsek ◽  
Aneta Minaříková
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Chemical Formula ◽  
Charge Balance ◽  
Skarn Deposit ◽  
Crystalline Complex ◽  
The Czech Republic

Abandoned iron skarn deposit Hraničná is located 16 km NW of Jeseník, Silesia, Czech Republic. It is situated in the Staré Město Crystalline Complex, belt of high grade metamorphic rocks, which suppose to be a meta-ophiolite of the initial Cambro-Ordovican rifting. The deposit itself is formed by two stratiform magnetite-hematite bands within the marbles and quartz-rich biotite gneisses. Marbles containing silicates are rich in Zn and Pb and give evidence for sedimentary of volcanosedimentary origin of the ore accumulation. We collected several samples at the adit and +20 m levels of the mine which yielded phosphohedyphane. Mineral forms irregular aggregates up to 100 μm within the calcite-dolomite-magnetite skarn. Its average chemical formula from 7 WDS spots is (Ca2.07Sr0.03Ba0.01Mg0.02Pb3.23Zn0.01Fe0.09Al0.01)Σ5.47[(PO4)2.53(AsO4)0.03(SO3)0.01(SiO4)0.24]Σ2.81[Cl1.05F0.20]Σ1.25 based on 13 O+Cl+F. Use of the normalization to Ca1 + Ca2 = 5 and employing the charge balance could lead to the possible presence of (CO3)2- up to 0.60 apfu, resp. 3.61 hm. % CO2; this possible content do not have any effect on mineral classification. It is, therefore, fifth reported occurrence of this mineral in the territory of the Czech Republic and the Bohemian Massif.

scholarly journals A new specimen of Araucaria fricii from the early Coniacian of the Bohemian Massif, Central Europe

2021 ◽  
Vol 77 (2) ◽  
pp. 282-286
Author(s):  
Jiří Kvaček
Keyword(s):  
Czech Republic ◽  
Central Europe ◽  
Bohemian Massif ◽  
Type Material ◽  
Massif Central ◽  
The Czech Republic ◽  
First Occurrence ◽  
Bohemian Cretaceous Basin ◽  
Cone Scale

A specimen of Araucaria fricii is described from the upper part of the Teplice Formation in the Bohemian Cretaceous Basin. It extends the first occurrence of A. fricii from the mid-Coniacian back to the early Coniacian. Found in the Radovesice locality near Kučlín in the northern part of the Czech Republic, it is characterised by a deltoid cone scale complex with a centrally placed seed. It is compared to the type material of A. fricii from the mid-Coniacian Březno Formation and other European Cretaceous species of Araucaria. The taphonomy and palaeoecology of A. fricii is briefly discussed.

scholarly journals Magnetotelluric investigations of the seismically active region of Northwest Bohemia: preliminary results

1999 ◽  
Vol 42 (1) ◽  
Author(s):  
D. Di Mauro ◽  
G. Volpi ◽  
A. Manzella ◽  
A. Zaja ◽  
N. Praticelli ◽  
...  
Keyword(s):  
Czech Republic ◽  
Metamorphic Rocks ◽  
Depth Range ◽  
Entire Region ◽  
Scientific Cooperation ◽  
The Czech Republic ◽  
Metamorphic Basement ◽  
Final Data ◽  
Seismic Swarms ◽  
2D And 3D

During 1997, within the framework of an Italian-funded scientific cooperation between Italy and the Czech Republic, a series of magnetotelluric (MT) soundings was carried out in the region of Northwest Bohemia (Czech Republic). This is one of the most seismically active areas in Central Europe, where micro-earthquake swarms frequently occur during the apparently quiescent intervals between large macro-seismic swarms. Fifteen MT stations were installed in an area of about 15 ´ 20 km2 where 80% of the seismicity of the entire region has been recorded since 1986. The area showed a high electromagnetic noise, possibly of high cultural origin from the nearby industrial zone of the Sokolov basin, which affected both the electric and the magnetic signals. The final data, carefully selected, were modeled by 2D and 3D techniques. The results show an extensive conductive structure in the depth range from 0.5 to 3 km. This structure could be connected with the locally buried granitic massif in the inhomogeneous metamorphic basement, probably accompanied by fracturation, thermo-metamorphism or paleofluids. Moreover, the presence of a conductive anomaly in the northern part of the investigated region could be linked to a lithological change in the metamorphic rocks (prevalence of phyllites over mica schists), which would even increase the effect of the granite.

scholarly journals The raw material potential of the Czech Republic

2018 ◽  
Vol 9 (3) ◽  
pp. 23-27 ◽  
Author(s):  
Beáta Korandová ◽  
Alena Straková ◽  
Jiří Beránek ◽  
Dana Vrublová
Keyword(s):  
Czech Republic ◽  
Cost Effectiveness ◽  
Bohemian Massif ◽  
Statistical Data ◽  
Raw Materials ◽  
Low Cost ◽  
Raw Material ◽  
The Czech Republic ◽  
Environmental Limits ◽  
Environmental Interests

This article summarizes the information on raw materials in the Czech Republic. Although mining was significantly reduced not long ago, there are still rich deposits of ores, non-metallic raw materials, as well as energetic and construction ones. Many of them are potentially utilizable in future, especially those which are economically favorable, and their mining is not in any conflict with environmental interests. Deposits are distributed irregularly, and their raw materials are different in both the Bohemian Massif and Western Carpathians. In order to be complete, the text also comprises deposits, which are restricted by environmental limits or their mining promises a low-cost effectiveness. The article is amended with actual statistical data.

scholarly journals ZEMĚTŘESENÍ V HOSTĚRADICÍCH V ČERVNU 2014

2016 ◽  
Vol 22 (1-2) ◽  
Author(s):  
Jana Pazdírková ◽  
Jan Zedník ◽  
Ivan Prachař ◽  
Hana Krumlová ◽  
Pavel Zacherle
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Seismic Station ◽  
Historical Earthquakes ◽  
Local Magnitude ◽  
Southeastern Part ◽  
Epicentral Area ◽  
The Czech Republic ◽  
New Information ◽  
Southern Moravia

Southern Moravia – a southeastern part of the Czech Republic at the contact of the Bohemian Massif and the Carpathian Foredeep – is one of the regions with the lowest seismic activity in the Czech Republic. Reports on historical earthquakes in this area are sporadic and poorly evidenced, many of the messages are in fact observations of earthquakes originating mainly in Austria. Instrumental seismic monitoring in southern Moravia commenced in 1995. Thereafter only three local earthquakes were observed – magnitude 2.5 event near Hostěradice in 2000, perhaps induced event near Uhřice in 2003 with magnitude of 0.7 and magnitude 1.4 earthquake near Božice in 2006.A sequence of four weak earthquakes in June 2014 is only the fourth occurrence of earthquakes in southern Moravia since the beginning of instrumental measurements. Events originated near Hostěradice (SE margin of the Bohemian Massif), 40 km southwest of Brno. The strongest event reaching local magnitude of 2.0 occurred on June 1, 2014 at 00:43 UTC. It was felt by people close to the epicentre with a macroseismic intensity 4 European Macroseismic Scale EMS-98. A temporary seismic station was immediately installed in the epicentral area. The station recorded two of four shocks and helped to confi rm a focus position of the sequence: 48.95° N 16.24° E, depth 3 km.In 2014 a review of historical earthquakes in this region was conducted using new catalogues of historical earthquakes in neighboring countries in order to avoid confusion between local and regional phenomena. Some new information sources were found. In any case, historical earthquakes in this region are very rare and most of them are poorly substantiated.

Minerály těžké frakce arkózových pískovců z Tismic u Českého Brodu (perm blanické brázdy, Česká republika)

2021 ◽  
Vol 29 (2) ◽  
pp. 337-350
Author(s):  
Zdeněk Dolníček ◽  
Jana Ulmanová
Keyword(s):  
Czech Republic ◽  
Chemical Composition ◽  
Bohemian Massif ◽  
Sedimentary Basin ◽  
Hydrothermal Activity ◽  
Heavy Mineral ◽  
Burial Diagenesis ◽  
Crystalline Complex ◽  
Variable Chemical ◽  
Tio2 Phase

The heavy mineral concentrate originating from Permian freshwater sandstones/arkoses from the Tismice site (northern part of the Blanice Furrow, Bohemian Massif, Czech Republic) was studied in terms of mineral composition and chemical composition of selected phases. Ilmenite, to various degree altered to a TiO2 phase and/or unidentified non-stoichiometric Fe-Ti (hydro)oxides, is the predominating constituent of heavy mineral fraction. Garnet, tourmaline, apatite and baryte are subordinate components. Garnet (with commonly etched “drusy” surface) belongs exclusively to almandine (Alm45-91Prp4-27Sps1-32Grs0-17Adr0-5). Tourmaline has variable chemical composition, but oxy-dravite prevails. Accessory phases include biotite, REE-rich goyazite (Goy45-59Flo29-43Cra11-17Gor0-1), zircon, pyrite, limonite, gahnite (Ghn57-68Hrc21-32Spl7-10Mgt1-2Gal1), staurolite, xenotime and monazite. Baryte and goyazite were likely formed during diagenesis of the host sediments or during later hydrothermal activity. Detrital garnet and tourmaline were probably sourced from the granulites, mica schists and migmatites of the Malín segment of the neighbouring Kutná Hora Crystalline Complex (KHCC). Surprisingly, amphibolites or serpentinites, frequently present in areas of the KHCC more proximal to the Permian sedimentary basin, did not contribute their garnets. We suggest that these areas were not exposed to erosion during the Permian period. Spectacular etching of surface of garnets and pervasive alteration of ilmenite were associated with burial diagenesis of the host sediments.

scholarly journals Minerály kontaminovaných granitových pegmatitů z lomu Pohled u Havlíčkova Brodu (moldanubikum), část I: oxidy, karbonáty, silikáty a fosfáty

2020 ◽  
Vol 28 (1) ◽  
pp. 132-151 ◽  
Author(s):  
Zdeněk Dolníček ◽  
Karel Malý ◽  
Jana Ulmanová ◽  
Jaroslav Havlíček ◽  
Luboš Vrtiška
Keyword(s):  
Czech Republic ◽  
Mineral Composition ◽  
Bohemian Massif ◽  
Small Body ◽  
Coarse Grained ◽  
Metamorphic Rocks ◽  
Granitic Pegmatites ◽  
Ore Minerals ◽  
Magmatic Stage

In the Pohled quarry near Havlíčkův Brod town (central part of Czech Republic), granitic pegmatites form dikes or irregular bodies cementing breccia of host metamorphic rocks (paragneisses, amphibolites) belonging to the Monotonous (Ostrong) Group of the Moldanubicum of the Bohemian Massif. Pegmatites exhibit coarse-grained textures and very simple mineral composition, which, however, was in places strongly modified by superimposed hydrothermal alterations and locally also by crystallization of ore minerals. K-feldspar, plagioclase (An0-38), biotite (phlogopite), apatite (fluorapatite to hydroxylapatite), zircon, allanite-(Ce) and part of quartz undoubtedly originated during magmatic stage. Products of hydrothermal alterations include younger quartz, Fe-Mg chlorites (older clinochlore and younger chamosite with an admixture of Ca-smectite), prehnite, clinozoisite, amphibole (actinolite), titanite, calcite, and very probably also ilmenite (with up to 22.5 mol. % of pyrophanite), rutile, anatase and V-Cr-Fe-rich grossular with 13 - 25 mol.% of goldmanite and 12 - 24 mol.% uvarovite. The elevated contents of Mg, Ca, V and Cr found in some minerals are associated with a material contamination by the surrounding metamorphic rocks (especially amphibolites, serpentinites and perhaps also graphitic lithologies), which took place with varying intensity during both magmatic and hydrothermal stages of evolution of the studied pegmatites. Geochemically, they are poorly fractionated pegmatites, whose origin was probably connected with anatexis of the host Moldanubian metamorphic rocks, which was likely associated with emplacement of adjacent small body of the Pohled Granodiorite.

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