Journal of Geosciences最新文献

{"title":"Pokhodyashinite, CuTlSb2(Sb1-xTlx)AsS7-x, a new thallium sulfosalt from the Vorontsovskoe gold deposit, Northern Urals, Russia","authors":"A. Kasatkin, J. Plášil, E. Makovicky, R. Škoda, A. Agakhanov, M. V. Tsyganko","doi":"10.3190/jgeosci.342","DOIUrl":"https://doi.org/10.3190/jgeosci.342","url":null,"abstract":"Pokhodyashinite CuTlSb 2 (Sb 1– x Tl x )AsS 7– x , is a new sulfosalt from the Vorontsovskoe gold deposit, Sverdlovsk Oblast’, Northern Urals, Russia. It forms anhedral grains up to 0.1 × 0.05 mm in size in calcite and is associated with major orpi-ment, pyrite, realgar and minor baryte, clinochlore, As-bearing fluorapatite, harmotome, prehnite, native gold and a rich spectrum of sulfosalts. Pokhodyashinite is black, opaque, and has a metallic luster and a black streak. It is brittle, with an uneven fracture and poor cleavage on {100}. The Vickers hardness (VHN, 20 g load) is 55 kg/mm 2 , corresponding to a Mohs hardness of 2. The calculated density is 5.169 g/cm 3 . In reflected light, pokhodyashinite is grayish-white, bireflectance is distinct. In crossed polars, it is strongly anisotropic; rotation tints vary from dark brownish gray to light bluish-gray. No internal reflections are observed. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the IMA are ( R min / R max , %): 28.9/34.6 (470 nm), 27.6/33.4 (546 nm), 26.7/32.4 (589 nm), 26.1/31.1 (650 nm). The empirical formula of pokhodyashinite based on Σ Me = 6 apfu is Cu","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46542237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Hg-Pd-Te system: phase relations involving temagamite and a new ternary phase","authors":"M. Drábek, A. Vymazalová, F. Laufek, M. Tuhý","doi":"10.3190/jgeosci.332","DOIUrl":"https://doi.org/10.3190/jgeosci.332","url":null,"abstract":"Phase relations in the Hg–Pd–Te system were studied at 350 °C using the silica glass tube method. The following binary phases were confirmed to be stable at 350 °C: PdHg (potarite), HgTe (coloradoite), Pd13Te3, Pd20Te7 (keithconnite), Pd7Te3, Pd9Te4 (telluropalladinite), Pd3Te2, PdTe (kotulskite), and PdTe2 (merenskyite). Kotulskite (PdTe) dissolves up to 8 at. % Hg at 350 °C. Other palladium tellurides do not dissolve Hg. Two ternary phases were proved to be stable in the system at 350 °C: Pd3HgTe3 (temagamite) and a new phase Pd4HgTe3. The Pd4HgTe3 phase is orthorhombic, Pnma space group with unit-cell parameters a = 13.1520(2), b = 11.6879(2), c = 4.25758(5) Å, V = 654.480(5) Å3 and Z = 4. The Pd4HgTe3 phase can be viewed as a ternary ordered variant of the Hg-bearing kotulskite. Synthetic temagamite forms stable assemblages with several phases representing minerals merenskyite and coloradoite, coloradoite and potarite, merenskyite and kotulskite, phase Pd4HgTe3 and kotulskite s.s., and phase Pd4HgTe3 and potarite. The occurrence of temagamite and its associations indicate the formation of mineralization below 570 °C. The new phase Pd4HgTe3 forms stable associations with synthetic analogs of temagamite and potarite, potarite and telluropalladinite, telluropalladinite and kotulskite s.s., temagamite and kotulskite s.s. The phase Pd4HgTe3 can be expected to be found in such associations under natural conditions.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46746840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Foreword to the special issue “From experimental mineralogy and crystallography to mineral deposit: a tribute to Milan Drábek”","authors":"F. Laufek, J. Kotková","doi":"10.3190/jgeosci.330","DOIUrl":"https://doi.org/10.3190/jgeosci.330","url":null,"abstract":"","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49585115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Milan Drábek: Bright, productive, witty, provocative","authors":"J. Kotková","doi":"10.3190/jgeosci.338","DOIUrl":"https://doi.org/10.3190/jgeosci.338","url":null,"abstract":"","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44799555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amphibole and pyroxene as indicators of alkaline conditions in banded carbonatite-like marbles from Bližná, Český Krumlov Unit, Moldanubian Zone","authors":"Pavlína Radková, M. Novak, J. Cempírek, S. Houzar, R. Škoda","doi":"10.3190/jgeosci.336","DOIUrl":"https://doi.org/10.3190/jgeosci.336","url":null,"abstract":"1 Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic; radkova4@uniba.sk 2 Department of Mineralogy, Petrography and Geology of Mineral Deposits, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, 842 15 Bratislava, Slovakia 3 Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic * Corresponding author","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46839902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Miscibility between synthetic FeS and TiS: An insight into the phase relations in natural Ti-bearing iron monosulfides","authors":"N. Mészárosová, R. Skála, P. Mikysek, M. Drábek","doi":"10.3190/jgeosci.334","DOIUrl":"https://doi.org/10.3190/jgeosci.334","url":null,"abstract":"Syntheses of (Fe,Ti)S analogs of natural Ti-bearing troilites were performed in evacuated and sealed silica glass tubes to investigate the extent of the knowledge on the solid solution between FeS and TiS. The synthesized (Fe,Ti)S phases were investigated using electron probe microanalysis and powder X-ray diffraction. The synthetic phases of the (Fe,Ti) S series adopt NiAs-type structure of P63/mmc space group in the compositional range from FeS to Fe0.5Ti0.5S. Members of the series rich in titanium crystallize in the R–3m space group. The stoichiometric TiS can adopt both structure types. Some additional diffraction peaks were observed in numerous samples. However, due to the insufficient quality of powder XRD data, crystal structure parameters of only samples with troilite 2C superstructure could be successfully refined. Systematic variation of deficit in metal (Me = Fe + Ti) site occupancy with titanium content was observed in the synthetic samples. This deficit increases with the increasing Ti content in a compositional range from pure FeS to Fe0.2Ti0.8S. In samples containing more titanium than this composition, the deficit of the metal site occupancy decreases, and the composition of end-member TiS is very close to the ideal stoichiometry.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41478645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cronstedtite from Litošice, Czech Republic","authors":"J. Hybler, Z. Dolníček, J. Sejkora","doi":"10.3190/jgeosci.335","DOIUrl":"https://doi.org/10.3190/jgeosci.335","url":null,"abstract":"The layered iron silicate cronstedtite was encountered in ore veins in the exploration shaft mined in the Neoproterozoic black shale-hosted pyrite-manganese deposit near Litošice (Eastern Bohemia, Czech Republic) around 1955. It forms up to 2 mm thick black double or single bands in symmetrically zoned hydrothermal veins cutting shales. The specimens selected from available material were studied by single-crystal X-ray diffraction using the four-circle diffractometer with an area detector. The chemical composition of some of the specimens was determined by the electron probe microanalysis (EPMA) in the WDS mode. Furthermore, a polished section of the ore material with cronstedtite bands was prepared, and the mineral association was analyzed with the aid of back-scattered electron (BSE) images. The interpretation of reciprocal space (RS) sections produced by the diffractometer software allowed the determination of OD subfamilies (Bailey’s groups) A, B, C, D, and polytypes. The 1T polytype (subfamily C), a = 5.52, c = 7.12 Å, space group P31m, is the most abundant in the occurrence. In rare cases, it forms oriented crystal associations (allotwins) with the 1M polytype (subfamily A), a = 5.52 Å, b = 9.55, c = 7.136 Å, β = 104.4°, space group Cm. Fully disordered allotwinned crystals of the A + C subfamilies were found, too. In addition, few allotwins of the polytype 2H1 (subfamily D) with a small amount of 2H2, were identified. Unit cell parameters are a = 5.49, c = 14.21 Å, space groups are P63cm (2H1), and P63 (2H2). EPMA-WDS of selected crystals of prevailing 1T polytype revealed elevated contents of Mn (0.19–0.62 apfu) and low contents of Mg (up to 0.13 apfu) and Cl (up to 0.05 apfu), respectively. More rare 2H1 (+ 2H2) polytypes show elevated contents of Mg in the range of 0.19–0.62 apfu and distinctly lower Mn (up to 0.07 apfu) and Cl contents (up to 0.01 apfu). The BSE images reveal that cronstedtite bands are associated with multiple generations of carbonates (rhodochrosite, siderite, rarely magnesite and calcite), quartz, opal, pyrite and carbonate-fluorapatite. Intense metasomatic replacement of cronstedtite by opal and siderite appeared especially around the center of the studied vein.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44246947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin of V-Cr-Ti-mineralization in thermally overprinted metal-rich black shales from the Teplá-Barrandian Unit (Bohemian Massif) and implications for metal remobilization during metamorphism","authors":"F. Veselovský, J. Pašava, O. Pour, L. Ackerman","doi":"10.3190/jgeosci.337","DOIUrl":"https://doi.org/10.3190/jgeosci.337","url":null,"abstract":"We present a detailed study of geochemical composition and ore mineralogy of black shales from Chynín, Czech Republic, representing Ediacaran organic matter-rich sediments, which were subject to regional and contact metamorphism. They are part of the Blovice Accretionaly Complex (BAC) in the Teplá–Barrandian Unit (TBU) and are located close to the contact with the Central Bohemian Pluton (CBP). The black shales were encountered with metasilicites, metabasalts, and basic tuffitic rocks in the CHY-2 drill hole (250 m deep) and are regionally associated with hornfels bodies. The geochemistry of these shales indicates that they correspond to metal-rich black shales deposited under strongly reducing conditions (TOC/Pmolar > 100, high Mo and U values). On the other hand, the lack of a positive link between TOC and redox-sensitive metals (e.g., V, U, Cr, Ni, Mo) and their generally negative correlation with sulfur indicate important late-stage metal and sulfur remobilization. This is reflected in the mineralogical composition of the shales, which documents a thermal event in their history. Abundant framboidal pyrite (pyrite I) was recrystallized into coarse aggregates (pyrite II), locally accompanied by chalcopyrite, sphalerite, and rare molybdenite, pentlandite and breithauptite. Abundant pyrrhotite formed there due to selective desulfurization of pyrite I and II during the contact metamorphism. Locally, this process was also accompanied by the replacement of pyrrhotite by V–Cr–O (karelianite – V2O3 and eskolaite – Cr2O3, mostly with dominant karelianite end-member) and Ti–V–O (vanadium rutile, schreyerite – V2Ti3O9 and a phase with the theoretical composition V4Ti3O12, yet unknown to the mineralogical system). Vanadium–Cr–Ti elemental associations reported from different localities of Neoproterozoic metal-rich black shales, metal-rich black shales, and (meta)silicites in TBU indicate similar sources of these elements but different conditions of their accumulation.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48019294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perryite, (Ni,Fe)16PSi5, from the Mount Egerton aubrite: the first natural P-Si-ordered phosphide-silicide","authors":"S. Britvin, S. Krivovichev, O. Vereshchagin, N. S. Vlasenko, V. Shilovskikh, M. Krzhizhanovskaya, M. S. Lozhkin, E. Obolonskaya, Yulia O. Kopylova","doi":"10.3190/jgeosci.331","DOIUrl":"https://doi.org/10.3190/jgeosci.331","url":null,"abstract":"Perryite, natural Ni-silicide, is a minor but regular constituent of the metal phase in enstatite chondrite (aubrite) and enstatite chondrite meteorites. Its synthetic analog was shown to have promising catalytic properties. The first-time solution of the crystal structure of natural perryite was completed on the material from the Mount Egerton aubrite. The mineral is trigonal, R3̄c, a = 6.6525(5), c = 37.998(5) Å, V = 1456.3(3) and Z = 6. The structure was refined to R1 = 0.0137 based on 457 independent observed reflections. The chemical formula obtained from the structure refinement, (Ni14.14Fe1.88)Σ16.02PSi5, agrees with that derived from the electron microprobe data, (Ni13.39Fe2.65Co0.01)Σ16.05P1.22Si4.74. This research showed that P and Si in perryite are ordered, resulting in the simplified formula (Ni,Fe)16PSi8, in contrast to the currently accepted variant (Ni,Fe)8(Si,P)3. The detailed results of EBSD study reveal previously unknown relationships between perryite, associated α-(Fe,Ni) metal (also known as kamacite) and schreibersite, (Fe,Ni)3P. Since enstatitic meteorites represent the early stages of nebular accretion, our results demonstrate that the crystal-chemical factor could affect the differentiation of chemical elements upon the onset of the Solar System formation.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43158494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A word of the Editor-in-Chief","authors":"J. Plašil","doi":"10.3190/jgeosci.325","DOIUrl":"https://doi.org/10.3190/jgeosci.325","url":null,"abstract":"","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47007724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}