Bulletin Mineralogie Petrologie最新文献

{"title":"Minerály coronaditové skupiny z Třebíče - Boroviny a Řípova (Morava, Česká republika)","authors":"J. Jirásek, D. Matýsek, Aneta Minaříková","doi":"10.46861/bmp.30.137","DOIUrl":"https://doi.org/10.46861/bmp.30.137","url":null,"abstract":"Localities Třebíč - Borovina (GPS N 49° 12.400‘ E 015° 51.280‘) and nearby Řípov (N 49° 12.700‘ E 015° 50.850‘) are known since 19th century. They represent variegated residual rocks originated during Tertiary? weathering of marbles, dolomite marbles, calcic and magnesian skarns, quartzites and hornblendites intersected by aplites and granitic pegmatites. These rocks enveloped by the biotite gneisses and migmatites close to the contact with the Třebíč Pluton belong to the Moldanubian Zone of the Bohemian Massif. In the past, there was a short-time production of Fe-ore from the weathering zone at Třebíč - Borovina, as well as production of mineral raw-material for brickworks. Since the localities are inaccessible for a long time, we investigated 11 mineral samples of manganese oxidic minerals deposited in the museum collections (Museum Vysočina Třebíč, National Museum in Prague - Natural History Museum, Museum of the South-eastern Moravia in Zlín): 10 from Borovina and 1 from Řípov, labeled as pyrolusite, psilomelane, and wad. They usually form botryoidal black aggregates up to 20 cm in size. Powder X-ray diffraction proved the presence of the coronadite group minerals, accompanied by birnessite (one sample), kaolinite, quartz, gypsum, and minerals of the spinel and chlorite groups. Unit-cell parameters of the coronadite group minerals range as follows: a = 9.750 - 9.939 Å, b = 2.851 - 2.869 Å, c = 9.840 - 10.024 Å, and β = 88.66 - 90.77° (for the monoclinic space group 2/m). Scanning electron microscopy showed the botryoidal texture, where at least part of the zoning visible in back-scattered electrons is in fact the result of density of the mineral aggregate, alternating from massive to fibrous, sometimes with the atol microstructure. Empirical average mineral formulae, based on WDS analyses, are: hollandite from Borovina (Ba2+0.40 Ca2+0.16Mg2+0.13Cu2+0.03Zn2+0.02Pb2+0.01K+0.18Na+0.04)Σ0.98 [(Mn4+5.90Si4+0.06P5+0.04)Σ6.00 (Mn1.77Fe0.20Al0.11)3+Σ2.07] Σ8.07O16, cryptomelane from Borovina (K+0.51Na+0.04Ba2+0.20Ca2+0.09Zn2+0.05Cu2+0.03Mg2+0.02Pb2+0.02Co2+0.01)Σ0.97 [(Mn4+6.91 Si4+0.03P5+0.06)Σ7.00(Mn0.72Fe0.07Al0.06)3+Σ0.85]Σ7.85O16, and cryptomelane from Řípov (K+0.66Na+0.03Ba2+0.14Ca2+0.04 Zn2+0.03Cu2+0.01)Σ0.92[(Mn4+6.88Si4+0.03P5+0.09)Σ7.00 (Mn0.77Al0.11 Fe0.04)3+Σ0.93] Σ7.93O16. Most significant are substitutions Al3+ → Mn3+-1 and Fe3+ → Al3+-1 at the M3+ site, also Mg2+ → Ba2+-1 and Ca2+ → Ba2+-1 at the A2+ site in hollandite. Accessory minerals - baddeleyite and probable xenotime-(Y), present in the hollandite and cryptomelane aggregates, were identified only by EDS analyses.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70599913","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":"Supergénne minerály z U-Cu rudného výskytu Východná-Nižný Chmelienec v Nízkych Tatrách (hronikum, Slovensko)","authors":"Eva Hoppanová, Štefan Ferenc, Richard Kopáčik, Šimon Budzák, Tomáš Mikuš","doi":"10.46861/bmp.29.077","DOIUrl":"https://doi.org/10.46861/bmp.29.077","url":null,"abstract":"An association of supergene U-Cu and Y/REE minerals was found in a relic of old ore dump at the abandoned U deposit occurrence Východná-Nižný Chmelienec, the northern slopes of the Nízke Tatry Mts., Slovakia. They have partially recent origin, since exploration of the locality took place between 1965 and 1966. The studied mineral assem- blage is represented by goethite, malachite, uranophane and (meta)zeunerite, in a lesser extent baryte and rare zálesíite. Uranophane appears separately (globular aggregates, thin coatings) and it also forms the main part of the yellow to yellow-green crystalline crusts on the rock cracks. The chemical composition of the uranophane was determined by electron microprobe analyses and it is close to its ideal chemical formula Ca(UO2)2(SiO3OH)2·5H2O. The average chemical composition of the studied uranophane can be expressed by an empirical formula (Ca1.0Mg0.02K0.01Fe0.01Ba0.01)Σ1.05 (UO2)2.08(SiO3OH)1.84·5H2O. The infrared vibrational spectra of the studied uranophane show 3 (UO2)2+ at 850-760 cm-1; the 3 (SiO4)4- antisymmetric stretching vibration at 1000-900 cm-1; the 1 (SiO4)4- symmetric stretching vibration at 1150-1199 cm-1; the  H2O bending vibration at 1800-1600 cm-1 and OH stretching vibrations at 3407; 3408 and 3409 cm-1. The weak bands 2648; 2646 and 2651 cm-1 may be assigned to organic impurities. The calculated U-O bond length 1.83 Å corresponds to short U-O bonds in uranophane. The accessory admixtures of uranophane coatings are (meta)zeunerite and zálesíite. (Meta)zeunerite occasionally forms thin coatings of light green to emerald green tabular crystals (up tu 0.5 mm) on the surface of the rocks. Chemical analyses of (meta)zeunerite correspond to the empirical formula (Cu0.66K0.03Fe0.01Ca0.01)Σ0.71(UO2)2.11[(AsO4)1.96(PO4)0.01]Σ1.97·12H2O. Zálesíite occurs as crystalline aggregates, nests, formed by tiny acicular crystals, up to 100 µm in length. This is the second finding (occurrence) of this mineral in Slovakia. An average zálesíite chemical composition is (Ca0.83REE0.18U0.05Al0.03Ti0.01)Σ1.10(Cu5.81Fe0.06Zn0.02)Σ5.90[(AsO4)2.75 (SiO4)0.21(PO4)0.02(SO4)0.03]Σ3.01(OH)5.10·3H2O. Malachite, which has been also found in the association, is only a minor mineral in the studied locality. The formation of uranyl silicates (uranophane) and minerals of the mixite group (zálesíite), present at the studied locality, points to neutralization of acidic supergene fluids in the mine dumps. Possibly, this environment later (precipitation of baryte) passed to neutral or slightly basic conditions (precipitation of carbonates - malachite). The identified uranyl phosphates/arsenates (zeunerite/metazeunerite), typical of an acidic environment, are therefore rare.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598365","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":"Böhmit a doprovodná zeolitová mineralizace ze Soutěsek u Děčína (Česká republika)","authors":"P. Pauliš, Libor Hrůzek, Oldřich Janeček, Z. Dolníček, Luboš Vrtiška, Radana Malíková, Ondřej Pour, F. Fediuk","doi":"10.46861/bmp.29.164","DOIUrl":"https://doi.org/10.46861/bmp.29.164","url":null,"abstract":"A new locality of böhmite and zeolite minerals, called „Soutěsky above the quarry“, occurs near the quarry „Soutěsky“ on the SW slope of the Hlídka hill, eastward of the Soutěsky village, about 5 km SW od the town of Děčín (Czech Republic). The mineralization is bound to vugs of Cenozoic volcanics. Böhmite forms mostly whitish to brownish hemispherical to spherical clusters up to 5 mm in size. The unit-cell parameters of böhmite, refined from the X-ray powder data, are a 2.871 (3), b 12.216(9), c 3.699(4) Å and V 129.7(2) Å3. Chemical analyses correspond to the empirical formula (Al0.92 Si0.06)Σ0.98O(OH). The following zeolites have been found in association with böhmite: thomsonite-Ca, phillipsite-K, gismondine, chabazite-Ca and analcime, as well as calcite. Minerals crystallized in following succession: calcite I → phillipsite-K → böhmite → calcite II → thomsonite-Ca → gismondine → calcite III. Independently, (older) analcime and (younger) chabazite-Ca occur. These minerals probably crystallized from low tempered solutions, enriched in Al ions and alkalies, the source of which can be found in altered rock-forming alumosilicates (analcime, nepheline).","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598479","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":"Ranciéit a doprovodné minerály z Rychaltic u Frýdku-Místku (Morava, Česká republika)","authors":"D. Matýsek, J. Jirásek, Aneta Minaříková, P. Skupien","doi":"10.46861/bmp.29.041","DOIUrl":"https://doi.org/10.46861/bmp.29.041","url":null,"abstract":"Recently described small outcrop of the upper part of the Barnasiówka Formation yielded several manganese oxidic minerals. Outcrop at the bank of the Krnalovice Stream (GPS N 49°38.623’ E 018°14.630’) consists of Lower Turonian greenish to grey-black laminated claystone alternating with grey chert. The whole sequence is a part of the Baška facies of the Silesian Unit, Outer Western Carpathians. In the middle part of the profile occur concretional aggregates containing manganese minerals. The central pale part of these aggregates is composed of quartz (ca. 90 wt.%), albite (ca. 9 wt.%), and muscovite, the darker rim of quartz (ca. 80 wt.%), goethite (ca. 10 wt.%), illite, todorokite, plagioclase, K-feldspar, and pyrite. Occasionally, remains of Mn-rich siderite were preserved in the cores. We suppose that they are in fact weathering products of carbonate-rich silicites. Manganese oxides also enter fissures in form of thin black coatings. Powder X-ray diffraction proved the presence of todorokite, ranciéite, pyrolusite, and possible vernadite. Todorokite forms black coatings with submetallic lustre, often associating with ranciéite. Ranciéite is dark pink to pinkish-brown, with a metallic lustre. Back-scattered electron images reveal its extremely thin tabular, sometimes undulated crystals and hexagonally oriented intergrowths. Powder diffraction data are strongly affected by preferred orientation, with dominating basal reflections of 001 plane at 7.4849 Å and plane 002 at 3.7424 Å. Its average formula from nine WDS spots (Ca0.14Mg0.01Ba0.01K0.01)Σ0.17(Mn4+0.86Si0.02Al0.03Fe0.01)Σ0.92O2.00·0.88H2O (based on 2 anions, water calculated from the ratio of cation sum / H2O in the formula according to Post et al. 2008) and CaO/MnO2 ratio 9 to 12 correspond well to the published data for this phase. Ranciéite is a rather common phyllomanganate from various geological environments, but this locality represents its first unambiguous occurrence in the Czech Republic. It closely resembles the one from Polish flysch Carpathians from Nowa Wieś near Rzesów.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598571","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":"New data on sulphosalts from hydrothermal siderite-type veins in the Spišsko-gemerské rudohorie Mts. (eastern Slovakia): 1. Nuffieldite and aikinite from Slovinky-Došťavná vein","authors":"M. Števko, J. Sejkora, Ľudovít Dojčanský","doi":"10.46861/bmp.29.108","DOIUrl":"https://doi.org/10.46861/bmp.29.108","url":null,"abstract":"A new occurrence of nuffieldite was recently discovered in a siderite-type hydrothermal vein with sulphides in Došťavná near Slovinky, Spišsko-gemerské rudohorie Mts., Spišská Nová Ves Co., Košice Region, Slovakia. It forms lead-gray acicular crystals reaching up to 1 cm in size or aggregates up to 2.5 cm, which are enclosed in quartz-siderite matrix together with chalcopyrite, pyrite, tourmaline and chlorite. Nuffieldite is frequently replaced by minor aikinite, galena and native bismuth. The refined unit-cell parameters of nuffieldite (for the orthorhombic space group Pbnm) are: a 14.5313(16) Å, b 21.454(2) Å, c 4.0500(6) Å and V 1262.58(19) Å3. The average (n=145 analyses) empirical formula of nuffieldite from Slovinky-Došťavná based on Pb+Bi+Sb = 5 apfu is corresponding to Cu1.30Pb2.00Bi2.00(Pb0.30Bi0.30 Sb0.40)1.00(S7.12Se0.03)7.15. Aikinite forms microscopic, anhedral to subhedral grains or aggregates replacing nuffieldite. The average (n=29) empirical formula of studied aikinite based on (Cu+Pb)/2+(Sb+Bi) = 8 apfu is Pb3.83Cu3.76(Bi4.12 Sb0.09)4.21(S12.40Se0.03)12.03.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598588","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":"New data on sulphosalts from the hydrothermal siderite-type veins in the Spišsko-gemerské rudohorie Mts. (eastern Slovakia): 2. Jaskólskiite and associated sulphosalts from the Aurélia II vein near Rožňava","authors":"M. Števko, J. Sejkora, T. Mikuš, Z. Dolníček","doi":"10.46861/bmp.29.204","DOIUrl":"https://doi.org/10.46861/bmp.29.204","url":null,"abstract":"New samples of jaskólskiite were recently collected at the Aurélia II siderite-type hydrothermal vein with sulphides near Rožňava, Spišsko-gemerské rudohorie Mts., Rožňava Co., Košice Region, Slovakia. It forms lead-gray, irregular aggregates up to 1.5 × 1 cm in size, which are enclosed in quartz-siderite gangue. Aggregates of jaskólskiite are consisting of individual, subhedral acicular crystals to 2 mm long, strongly replaced by younger bournonite and associated with Bi-rich jamesonite, tetrahedrite-(Fe), tintinaite, native bismuth and ullmannite. Significant variation of Cu (from 0.04 to 0.23 apfu) and Bi contents (from 0.32 to 0.77 apfu) was observed in studied sample. The average (n = 69 analyses) empirical formula of jaskólskiite from Rožňava-Aurélia vein based on Pb+Bi+Sb = 4 apfu is corresponding to Pb2.11Cu0.13(Sb1.42Bi0.47)1.89S5.14. Bi-rich jamesonite is the most common sulphosalt at the studied locality and it forms prismatic crystals up to 2 cm or irregular aggregates to 3 cm in size. The Bi content in jamesonite is ranging between 0.49 to 1.69 apfu. Bournonite is also common and two compositional types were distinguished. The first, dominant type is represented by Bi-rich bournonite (containing up to 0.14 apfu Bi). The second type of bournonite, represented by thin ribbons shows significant enrichment in As (reaching up to 0.49 apfu), but has only minor content of Bi (up to 0.08 apfu). Tintinaite is rare and its average (n = 9) empirical formula based on sum of all atoms = 63 apfu is corresponding to (Pb9.67Ag0.06)9.73(Cu2.55Fe0.40Zn0.07)3.02(Sb10.19Bi5.37)15.56S34.59Cl0.10.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598740","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":"Zýkait z dolu Lehnschafter u Mikulova v Krušných horách (Česká republika) - popis a Ramanova spektroskopie","authors":"J. Sejkora, Roman Gramblička","doi":"10.46861/bmp.29.241","DOIUrl":"https://doi.org/10.46861/bmp.29.241","url":null,"abstract":"The zýkaite samples were found at abandoned Lehnschafter mine near Mikulov in the Krušné hory Mts. (Czech Republic). It occurs as irregular white to light greenish rounded to spherical aggregates up to 1.5 cm in size composed of tiny acicular crystals up to 5 - 10 μm in length. Its empirical formula can be expressed as (Fe3.79Al0.02)Σ3.81[(AsO4)2.66(PO4)0.20(SiO4)0.07]Σ2.93 (SO4)1.07(OH)0.44·15H2O (mean of 3 spot analyzes; on the basis of As+P+S+Si = 4 apfu).Zýkaite is probably monoclinic, with the unit-cell parameters refined from X-ray powder diffraction data: a 21.195(8), b 7.052(2), c 36.518(17) Å, β 91.07(2)° and V 5458(2) Å3. Raman spectroscopy documented the presence of both (AsO4)3- and (SO4)2- units in the crystal structure of zýkaite. Multiple Raman bands connected with vibrations of water molecules and (AsO4)3- groups indicate the presence of more structurally non-equivalent these groups in the crystal stucture of zýkaite.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70599156","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":"Minerály kontaminovaných granitových pegmatitů z lomu Pohled u Havlíčkova Brodu (moldanubikum), část II: prvky a sulfidy","authors":"Z. Dolníček, Jana Ulmanová, K. Malý, Jaroslav Havlíček, J. Sejkora","doi":"10.46861/bmp.29.090","DOIUrl":"https://doi.org/10.46861/bmp.29.090","url":null,"abstract":"In the Pohled quarry near Havlíčkův Brod town (central part of Czech Republic), texturally and mineralogically simple contaminated anatectic 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. They exhibit signs of intense hydrothermal overprint and also the presence of abundant disseminations, nests and veinlets of ore minerals. A detailed mineralogical study revealed the presence of an extraordinary rich ore assemblage (20 species in total, including one unnamed phase). The oldest minerals are sphalerite (rich in Fe), löllingite, Fe-Co-Ni sulphoarsenides (cobaltite, glaucodot, arsenopyrite, gersdorffite), pyrrhotite, galena and chalcopyrite, in later portion accompanied by inclusions of Bi-minerals (native bismuth, bismuthinite, joséite-A, joséite-B, ikunolite and a Pb-Bi sulphosalt). The composition of the Pb-Bi sulphosalt is equal to Ag,Fe-substituted eclarite; its identity was confirmed also by Raman spectrum. Pyrite is very abundant phase, present probably in several generations. The Fe-Co-Ni thiospinels disseminated in younger chlorite, and represented by siegenite, violarite, grimmite and an unnamed NiFe2S4 phase, are the youngest ore minerals. The mineral association as well as chemical composition of most ore minerals are well comparable to those of local polymetallic ore veins and Alpine-type veins, which give evidence for identical origin of all these ore mineralizations. The formation of pegmatite-hosted ore assemblage was long-lasting multiphase process, which took place at temperatures between ca. 350 and <120 °C during changing fugacities of sulphur, tellurium and oxygen. A distinct enrichment in cobalt and nickel of ore mineralization hosted by pegmatites (in comparison with hydrothermal veins) is explained in terms of pronounced interactions of fluids with amphibolites and serpentinites.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598529","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":"Cu(-Ag) mineralizace z Tismic u Českého Brodu (perm blanické brázdy, Česká republika)","authors":"Z. Dolníček, Nad'a Profantova, Jana Ulmanová","doi":"10.46861/bmp.29.197","DOIUrl":"https://doi.org/10.46861/bmp.29.197","url":null,"abstract":"A mineralogical study of samples newly collected from dump material at the formerly mined locality Tismice near Český Brod (central Bohemia) revealed the presence of covellite/yarrowite, acanthite, malachite and azurite. In addition, psammitic to aleuritic detrital material originated from host Permian sandstones/arkoses is a common compound of the studied ore samples. The Cu carbonates clearly prevail among ore minerals, whereas sulphide phases are accessories. The silver-enriched covellite/yarrowite, strongly replaced by malachite and azurite, has a coarse-grained texture implying that its primary hydrothermal or late hydrothermal origin cannot be excluded. The other recorded ore minerals are clearly supergene in origin. Although the nature of the mineralization from Tismice is in general similar to other occurrences of epigenetic vein Cu mineralization hosted by the Permian sediments in the vicinity of the town of Český Brod, the enrichment in silver is reported for the first time here.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598626","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":"Chemická zonálnosť Ti-andraditového granátu v Ca-skarne z oblasti Magnetový vrch pri Tisovci (Slovenská republika)","authors":"Peter Ružička, Pavol Myšľan, Martin Števko, Sergii Kurylo","doi":"10.46861/bmp.29.049","DOIUrl":"https://doi.org/10.46861/bmp.29.049","url":null,"abstract":"Analyzed garnets from the Magnet hill area near Tisovec (Slovak Republic) are part of a Ca-skarn mineral association consisting of diopside, clinochlore and calcite. Compositionally they correspond to Ti-rich andradite (Adr50.9-73.7) with minor grossular (Grs3.8-44.5) and schorlomite (Sch0.5-41.5) components. Garnets contain up to 13 wt. % TiO2 and in all of them YFe3+>YTi ratio prevails. Both sector and oscillatory chemical zoning were observed, which is primarily caused by variable distribution of Ti contents within individual garnet crystals. The three principal zones were distinguished in BSE imaging. The brightest are Ti-enriched zones with Ti content ranging from 0.85 to 0.50 apfu. Titanium gradually decreases in transitional zone (0.17 - 0.40 apfu) and reaches the minimum values in the dark zones (0.01 - 0.13 apfu). In the Ti-enriched zones the content of Si4+ and Al3+ is decreased due to substitution of Ti4+ and Fe3+ and assumed hydrogarnet substitution (SiO4)4- ↔ (O4H4)4-.","PeriodicalId":53145,"journal":{"name":"Bulletin Mineralogie Petrologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70598698","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}