{"title":"Příspěvek k petrografii a mineralogii lokality Vyskočilka (Praha-Malá Chuchle, silur Barrandienu)","authors":"Z. Dolníček, Dalibor Velebil, Jana Ulmanová","doi":"10.46861/bmp.31.047","DOIUrl":"https://doi.org/10.46861/bmp.31.047","url":null,"abstract":"Classical locality Vyskočilka in the Barrandian Basin displays a well-exposed section of black Silurian shales penetrated by a ca. 10-m thick diabase sill. We examined the petrographic character and mineral composition of the intrusive body and enclosing shales, as well as the hydrothermal veins cutting the rocks. The diabase is a rock with basic affinity (paleobasaltoid), which was strongly influenced by post-magmatic alterations including albitization and zeolitization of feldspars as well as chloritization of clinopyroxenes and Fe-Ti spinelides. Host sediments show variously intense thermal overprint at the contact with the sill. The predominating Silurian shales are rarely accompanied by laminites, formed by siliciclastic material, calcite, apatite and probably also a pyroclastic component. A minor component of all sediments are Ti-rich chromspinelides, which are classified as chromite, magnetite, and spinel. Chromspinelides form isolated euhedral single crystals reaching up to 50 µm in size, as well as their intergrowths and fragments, which all do not display marks of abrasion due to transport. We therefore presuppose that they represent relics of ultrabasic pyroclastic material (volcanic ash), which was deposited during sedimentation of Silurian sediments. There are known few sills of Silurian meimechites in the Prague Basin containing chromspinelides with comparable chemical composition, which can thus represent a likely source of chromspinelides. The vein hydrothermal mineralizations, present at the study site, probably originated during different geological processes. The calcite veins with minor quartz and hydrocarbons likely formed during Variscan tectono-thermal overprint of the area. By contrast, the vein mineralization containing calcite, quartz, titanite, anatase, and Zn-Fe-Ni-Cu sulphides was likely associated with contact-metamorphic processes related to intrusion of diabase.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"112 5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70600071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Železářská struska z polykulturní archeologické lokality Boršice v podhůří Chřibů","authors":"Z. Dolníček, Ladislav Kandrnál, Jana Ulmanová","doi":"10.46861/bmp.31.018","DOIUrl":"https://doi.org/10.46861/bmp.31.018","url":null,"abstract":"A piece of iron slag was found on an archaeological site near Boršice on the SE margin of the Chřiby Mts., Czech Republic, which is known by occurrence of artifacts from the Early Neolithic (5700 - 5000 BC), Bronze and Early Medieval Ages. We present results of laboratory investigation of this slag. It is composed mainly of fayalite laths, which belong to two generations, less occur glass phase, wüstite and leucite, exceptionally also metallic iron. The composition of fayalite displays unified chemical trend and ranges in rather narrow span (Fa93.7-96.3 DCS1.1-5.8Fo0.0-5.0Te0.0-0.2). The glass phase contains in addition to common compounds (Si, Fe, Al, alkalis) also elevated contents of P and Ca. The microstructure of the studied slag as well as chemistry of individual phases are very homogeneous across the whole sample. We interpret this slag as an iron smelting slag, originated during production of iron from ores using the direct method. The used ore was in all probability a limonite bog ore, whereas the use of local fresh and/or weathered pelosiderites is not probable on the basis of the recorded phase composition and chemical compositions of individual phases.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70600277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pauliš, Stanislav Kopecký, Z. Dolníček, J. Sejkora
{"title":"Sulfidická mineralizace s Au-bohatým stříbrem z Utína v havlíčkobrodském rudním revíru (Česká republika)","authors":"P. Pauliš, Stanislav Kopecký, Z. Dolníček, J. Sejkora","doi":"10.46861/bmp.31.025","DOIUrl":"https://doi.org/10.46861/bmp.31.025","url":null,"abstract":"Sulphide mineralization was found in relics of mine dumps from medieval mining near Utín, at SE part of the Havlíčkův Brod ore district (Bohemian-Moravian Highlands, Czech Republic). It is represented by pyrite, Fe-rich sphalerite, chalcopyrite, arsenopyrite, galena (with chemical compositions corresponding to other occurrences of this ore district) and more rare jamesonite and boulangerite. The main Ag ore was probably Ag-rich member of tetrahedrite group - kenoargentotetrahedrite-(Fe) with empirical formula (Ag5.45Cu4.48)Σ9.93(Fe1.75Zn0.32Mn0.01)Σ2.08Sb4.00S12.05. Another interesting mineral found in this association is Au-rich silver with Au contents in the range 53.35 - 56.40 wt. % and average empirical formula Ag0.60Au0.39. Schultenite, minerals of the pharmacosiderite group and inhomogeneous Fe-arsenates were detected from the rarely represented supergene mineralization.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70599948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Forsterit-serpentinový mramor s klinohumitem a spinelem u Chotěboře (moldanubikum; Český masiv); příklad retrográdní metamorfózy dolomitického mramoru","authors":"Stanislav Houzar","doi":"10.46861/bmp.31.010","DOIUrl":"https://doi.org/10.46861/bmp.31.010","url":null,"abstract":"A body of dolomite marble near Chotěboř was found in migmatized biotite paragneiss of the Moldanubicum directly on the border with migmatites/orthogneisses of the Kutná Hora Crystalline Complex. The area underwent significant tectonic reworking of rocks along the Přibyslav mylonite zone. Therefore, only small relics of early prograde HT/LP metamorphism at T > 650 - 700 °C were preserved in this marble. They are represented by the assemblage dolomite+calcite+forsterite+Zn-spinel+clinohumite ±Ba-phlogopite and rare baddeleyite. This mineral assemblage underwent strong low-temperature retrograde metamorphism (< 400 - 300 °C) under the conditions of high H2O activity (XCO2 < 0.10 - 0.15), which was manifested by almost complete serpentinization of forsterite. Partial alteration of clinohumite produced serpentine with numerous inclusions of a TiO2-mineral and rare sphalerite. The examined serpentine marble (ophicalcite) is lithologically and mineralogically similar to the dolomite marbles found in the Strážek Moldanubicum.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70600197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ammoniozippeite from the Jáchymov ore district, Krušné hory Mountains (Czech Republic) - description and Raman spectroscopy","authors":"J. Sejkora, Z. Dolníček, J. Plášil","doi":"10.46861/bmp.31.001","DOIUrl":"https://doi.org/10.46861/bmp.31.001","url":null,"abstract":"We have undertaken a study of the rare ammonium uranyl sulphate mineral, ammoniozippeite, from the Jáchymov ore district, Krušné hory Mountains (Czech Republic). It has been found on a few specimens and forms rich crystalline aggregates in thin cracks of supergene altered rocks with uraninite veinlets in association with gypsum. Its radially arranged aggregates are composed by well-developed flattened acicular crystals up to 1 mm in length. Ammoniozippeite is bright yellow and locally even yellow-orange with pale yellow streak and fluoresces yellow, weak or dull under 254 nm and 366 nm UV-radiation, respectively. Ammoniozippeite crystals are transparent to translucent and have an intensive vitrous luster. It is a very brittle and at least one system of perfect cleavage (along {010}) was observed. The quantitative chemical analyses of ammoniozippeite agree well with the proposed ideal composition and correspond to the following empirical formula [(NH4)1.96K0.11]Σ2.07[(UO2)2(SO4)1.98O2.06]·H2O (on the basis of 2 U atoms pfu). Ammoniozippeite is orthorhombic, the space group Ccmb, with the unit-cell parameters refined from X-ray powder diffraction data: a 8.7862(13), b 14.1579(19), c 17.162(2) Å and V 2134.8(4) Å3. Vibrational (Raman and infrared) spectroscopy documented the presence molecular water, ammonium, uranyl and suphate units in the crystal structure of ammoniozippeite.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70600112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pauliš, Libor Hrůzek, J. Sejkora, Oldřich Janeček, Ondřej Pour, Bohuslav Bureš, Blanka Šreinová
{"title":"Zeofylit, tobermorit, fluorapofylit-(K) a doprovodná zeolitová mineralizace z Křížového vrchu u Cvikova \u0000v Lužických horách (Česká republika)","authors":"P. Pauliš, Libor Hrůzek, J. Sejkora, Oldřich Janeček, Ondřej Pour, Bohuslav Bureš, Blanka Šreinová","doi":"10.46861/bmp.31.065","DOIUrl":"https://doi.org/10.46861/bmp.31.065","url":null,"abstract":"Zeophyllite, tobermorite, kenotobermorite, fluorapophylite-(K) and associated zeolites were found in cavities of Cenozoic basaltic rocks of small abandoned quarry at western slope of the Křížový vrch hill (443 m a.s.l.), 1.5 km NE from Cvikov, 13 km NNE from Česká Lípa, Lužické hory Mountains, Czech Republic. Zeophyllite forms colorless spherical aggregates with pearly lustre usually 3 - 4 mm in size, aggregates with diameter up to 1 cm were observed only rarely. It is trigonal, space group R-3, with unit-cell parameters refined from PXRD: a 9.362(2), c 36.470(12) Å and V = 2768.3(1.2) Å3. Chemical analyses of zeophyllite correspond to the empirical formula (Ca12.84Na0.07)Σ12.91(Si9.83Al0.26)Σ10.09 O28(OH)1.43 F8.42· 6H2O. Tobermorite occurs as snow-white hemispherical to spherical aggregates up to 1 cm in size, it replaces earlier zeophyllite. It is monoclinic, space group Bm, with unit-cell parameters refined from PXRD: a 6.714(4), b 17.375(4), c 22.670(8) Å, γ 123.31(3)° and V 938.2(1.3) Å3. On the base of chemical analyses, tobermorite with empirical formula (Ca4.55Na0.03K0.02)Σ4.60(Si5.40Al0.60)Σ6.00O15.56(OH)1.44·5H2O is accompanied by more rare Ca-poor kenotobermorite with empirical formula (Ca3.99Na0.04)Σ4.03(Si5.60Al0.40)Σ6.00O14.62(OH)2.38·5H2O. Fluorapophyllite-(K) forms abundant prismatic crystals up to 0.5 - 2 cm in size. It is colorless to white with vitreous to greasy lustre. It is tetragonal, space group P4/mnc, with unit-cell parameters refined from PXRD: a 9.0157(13), c 15.7889(19) Å and V = 1283.4(3) Å3. Chemical analyses of fluorapophyllite-(K) correspond to the empirical formula (K0.81Na0.24)Σ1.05Ca4.06(Si7.25Al0.47)Σ8.00O20F1.05· 8H2O. Other zeolites, thomsonite-Ca, chabazite-Ca, phillipsite-Ca and -K, were found in association; their PXRD data, unit-cell parameters and chemical compositions are given in the paper.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70600534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}