Journal of Geosciences最新文献

{"title":"Chemical composition and Raman spectroscopy of aerugite, xanthiosite, and a natural analog of KNi3(AsO4)(As2O7) from Johanngeorgenstadt, Germany","authors":"Iwona KORYBSKA-SADŁO, Adam Szuszkiewicz, Marta Prell, Piotr Gunia","doi":"10.3190/jgeosci.361","DOIUrl":"https://doi.org/10.3190/jgeosci.361","url":null,"abstract":"Aerugite Ni 8.5 (AsO 4 ) 2 As 5+ O 8 and xanthiosite Ni 3 (AsO 4 ) 2 , two rare anhydrous arsenates, have been identified in a historic sample from Johanngeorgenstadt, Saxony, Germany. The minerals have been characterized through scanning electron microscopy, electron microprobe analysis and Raman spectroscopy for the first time. They are mostly dark-green (aerugite) to light-green (xanthiosite) fine-grained or microcrystalline crusts on a quartz matrix in association with barite, bunsenite, dolomite, and rooseveltite. Aerugite forms up to 200 μm large pseudo-hexagonal platy crystals, whereas xanthiosite forms short prisms to nearly equant forms, often with indistinct, poorly-developed and rounded faces. The chemical composition of the two minerals can be expressed by the empirical formulas: (Ni 7.92 Co 0.52 Cu 0.06 ) Σ8.50 (As 1.00 O 4 ) 2 As 1.00 O 8 with traces of Bi (aerugite, mean of 4 analyses, based on 32 oxygens) and (Ni 2.85 Co 0.12 Cu 0.03 ) Σ3.00 (As 1.00 O 4 ) 2 (xanthiosite, mean of 5 analyses, based on 32 oxygens). The Raman spectra of both minerals lack bands related to OH stretching vibrations and are dominated by antisymmetric ν 3 and symmetric ν 1 As–O vibrations in AsO 4 polyhedra centered at 817, 846 and 886 cm –1 in the case of aerugite and at 786, 808, 826 and 843 cm –1 in xanthiosite. Bands from stretching vibrations As-O in AsO 4 polyhedra are located at 728 and 735 cm –1 in aerugite and are slightly displaced to 726 and 747 cm –1 in xanthiosite. The Raman spectrum of aerugite also contains well-defined 692, 675 and 658 cm –1 bands due to the stretching mode of NiO 6 octahedra, a broad feature at 576 cm –1 probably from a number of modes connected with AsO 6 octahedra. On the other hand, the xanthiosite spectrum displays a number of low-intensity, well-defined bands related to antisymmetric ν 4 and ν 2 symmetric bending vibrations in AsO 4 below 700 cm –1 as well as to lattice vibrational modes and Ni-O interactions below 250 cm –1 . Locally, the interstices between xanthiosite grains are filled with cryptocrystalline mass with the mean chemical composition of (K 0.90 Ba 0.01 ) Σ0.91 (Ni 2.86 Co 0.11 Cu 0.05 ) Σ3.02 (As 1.00 O 4 )(As 2.1 O 7 ) with traces of Na (mean of 7 analyses, based on 11 oxygens). The recorded Raman spectrum, with a strongly overlapping xanthiosite-related signal, lacks bands of water molecules or OH groups and contains bands related to the As–O–As vibration modes attributed to pyroarsenate As 2 O 7 groups. Although it was impossible to obtain more detailed data on crystal structure, we suggest this is the first reported natural occurrence of KNi 3 (AsO 4 )(As 2 O 7 ) phase.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44364857","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":"Molybdenum isotopic composition of molybdenite and the fertility potential of the Ekomédion U–Mo prospect, SW Cameroon","authors":"V. F. Embui, Cheo Emmanuel, Suh, Bernd Lehmann, Lukáš Ackerman","doi":"10.3190/jgeosci.363","DOIUrl":"https://doi.org/10.3190/jgeosci.363","url":null,"abstract":"We present Mo isotope data for molybdenite from the Ekomédion U–Mo prospect, SW Cameroon, a Late Neoproterozoic granite–pegmatite–quartz vein system. Disseminated and veinlet-controlled molybdenite in granite and pegmatitic pods yields a narrow range of δ 98 Mo values from – 0.06 to + 0.24 ‰, with two overlapping populations of + 0.03 ± 0.07 ‰ (n = 4) in granite, and slightly heavier of + 0.11 ± 0.10 ‰ (n = 5) in pegmatite. By contrast, molybdenite from a quartz– muscovite vein has an isotopically heavy δ 98 Mo value of + 1.61 ‰. We interpret this trend from granite through pegmatite to vein system towards isotopically heavy Mo to reflect the fractionation of an evolving magmatic–hydrothermal system. Furthermore, the LREE-enriched bulk-rock patterns with largely negative Eu anomalies and the overall enrichment of HREE in zircon indicate plagioclase fractionation as the dominant petrogenetic process during melt evolution. Furthermore, the presence of accessory ilmenite indicates relatively reducing conditions of the melt system, unfavorable for significant Mo accumulation. Therefore, the Ekomédion granite system seems to have limited economic potential for molybdenum despite the advanced degree of magmatic evolution.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49349274","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":"Stalactitic rhodochrosite from the 25 de Mayo and Nueve veins, Capillitas, Catamarca, Argentina: Physical and chemical variations","authors":"María Florencia, MÁRQUEZ-ZAVALÍA, James R. Craig","doi":"10.3190/jgeosci.354","DOIUrl":"https://doi.org/10.3190/jgeosci.354","url":null,"abstract":"Capillitas is an epithermal vein-type deposit in Argentina known for its mineralogical diversity, with more than one hundred and twenty described minerals, including five new species, and for the presence of banded and stalactitic rhodochrosite. Stalactites occur as single or combined cylinders of different sizes, from a few cm to 1.36 m in length and diameters up to 8 cm. Their cross-sections may show diverse aspects: from simple concentric banding to more intricate textures, whereas their external surface can be smooth, with undulations or with a poker-chip-like texture. The color of the stalactites varies from white to raspberry pink, with occasional brown bands toward the edges corresponding to a variety of rhodochrosite called “capillitite”. The contents of MnO range from 27.50 to 61.71 wt. % as it may be significantly replaced by CaO, FeO, ZnO and MgO. Replacements are reflected in the various shades of pink and brown displayed by this mineral. The different substitutions in the pink specimens exert only a minor influence on the unit cell parameters, whereas, in the brown variety, their size is significantly smaller with average values for pink rhodochrosite ( n = 24): a 4.776 Å, c 15.690 Å and a cell volume of 310.3 Å 3 , whereas, “capillitite” unit-cell parameters ( n = 7) are: a = 4.739, c = 15.558 with a unit-cell volume of 302.6 Å 3 . Conditions of formation of the banded rhodochrosite of the 25 de Mayo vein, obtained from fluid inclusions data, indicate temperatures of 145 ° to 150 °C and salinities of up to 4 wt. % NaCl(eq). The formation of the stalactites is explained by the infiltration of epithermal aqueous liquid, oversa - turated with Mn and bicarbonate, into a transiently vapor-filled, isolated cavity.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44357037","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":"Morphology and Raman spectral parameters of Bohemian microdiamonds: implications to elastic geothermobarometry","authors":"P. Jakubová, J. Kotková, R. Wirth, R. Škoda, J. Haifler","doi":"10.3190/jgeosci.356","DOIUrl":"https://doi.org/10.3190/jgeosci.356","url":null,"abstract":"In this work, we combine the morphology and internal structure of northwestern Bohemian microdiamonds with their Raman spectral parameters to describe and understand their relationship. We evaluate our data according to the theory of elasticity and discuss implications for elastic geothermobarometry of diamond inclusions in garnet. We conclude that microdiamonds enclosed in kyanite, garnet and zircon differ in morphology and internal structure depending on the type of the host rock and host phase. Single crystal diamond octahedra in kyanite in the acidic gneiss show predominantly Raman shift towards higher wavenumbers (upshift), while single and polycrystalline diamonds enclosed in garnet and zircon in the intermediate garnet–clinopyroxene rock yield more variable Raman shift including a shift towards lower wavenumbers (downshift). This is consistent with closed boundaries between diamond and kyanite observed using FIB-TEM, while interfaces between diamond and garnet or zircon are commonly open. Moreover, higher variability in the Raman shift in diamond hosted by garnet or zircon may be caused by complex internal structure and the presence of other phases. At the same time, a diamond in kyanite features relatively high full-width-at-half-maximum ( FWHM ) due to the anisotropy of thermal contraction, which is reflected by the plastic deformation of diamond mediated by dislocation glide at T ≥ 1000 °C. The entrapment pressure ( P trap ) for diamonds in garnet was calculated using elastic geobarometry to test its compatibility with the existing peak pressure estimated by conventional thermobarometry. The “downshifted” diamonds exhibit entrapment pressures of 4.8 ± 0.14 and 4.99 ± 0.14 GPa at an entrapment temperature of 1100 °C, using unstrained reference diamond from the literature and own measurements, respectively. This is consistent with the earlier estimates and the elastic theory and does not require any elastic resetting suggested to account for the reported upshift in garnet. Our data suggest that the upshift in diamond hosted by garnet is related to the proximity of other diamond grains. We conclude that the use of diamond inclusions in elastic barometry should be backed by careful evaluation of its internal structure and associated phases and restricted to isometric monocrystalline diamond grains not occurring in clusters as required by the method.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46021136","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":"Sample preparation and chromatographic separation for Sr, Nd, and Pb isotope analysis in geological, environmental, and archaeological samples","authors":"Erban-Kochergina Y.V., E. V., HO J.M.","doi":"10.3190/jgeosci.357","DOIUrl":"https://doi.org/10.3190/jgeosci.357","url":null,"abstract":"In countless modern geochemical studies, diverse biological and geologic samples are analyzed for Sr, Nd, and Pb isotopic composition. Such heterogeneity presents challenges for a “one-size-fits-all” approach to sample preparation, necessitating customization of sample preparation and chromatographic separation methods. We present (1) digestion techniques for low-Nd silicates, carbonatites, carbonates, water, plant and wood material, organic soils, aerosols collected via filtration, as well as archaeological samples (alloys, teeth, and bones) (2) a column chromatographic approach for samples with low concentrations (large amounts of a matrix) and (3) method verification via replicate analyses of a wide variety of isotopic standards.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47979148","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":"Pertoldite, trigonal GeO2, the germanium analog of α-quartz: a new mineral from Radvanice, Czech Republic","authors":"Z. V., Š. R., Laufek F., S. J., H. J.","doi":"10.3190/jgeosci.355","DOIUrl":"https://doi.org/10.3190/jgeosci.355","url":null,"abstract":"The new mineral pertoldite was found in a burning waste dump of abandoned Kateřina colliery at Radvanice near Trutnov, Hradec Králové Department, Czech Republic. The dump fire started spontaneously before 1980 and no anthropogenic material was deposited there. The determination of pertoldite as a natural analogue of synthetic trigonal α-GeO 2 is based on its chemical composition, X-ray powder diffraction data, and Raman spectroscopy. Pertoldite occurs as white to brownish aggregates resembling cotton tufts, up to 1 mm in size, composed of acicular crystals up to ~1 μm thick and up to 1 mm in length. Individual crystals are distorted, resembling textile fibers. Pertoldite was formed by direct crystallization from hot (400–500 °C) gasses containing Cl and F as transporting agents at a depth of 40–60 cm under the surface of a burning coal mine dump. It nucleated as a thin, delicate crust on a chip of siltstone together with multi-component aggregates of galena, stibnite, bismuthian antimony, greenockite, and bismuth. The ideal formula of pertoldite, GeO 2 , requires 100 wt. % GeO 2 . Germanium is partially substituted by silica (2.33–5.67 wt. % SiO 2 ), the extent of Ge 1 Si –1 substitution is limited to 0.03–0.09 apfu Si, and the empirical formula ranges between (Ge 0.91-0.97 Si 0.03-0.09 ) Σ1.00 O 2 . Pertoldite is trigonal, P 3 1 21 or P 3 2 21, a = 4.980(5) Å, c = 5.644(4) Å, with V = 121.2(2) Å 3 and Z = 3. The strongest reflections of the powder X-ray diffraction pattern [d (Å)/I ( hkl )] are: 4.315/44(100), 3.425/100(101,011), 2.490/31(110), 2.360/41(012,102), 1.867/31(112), 1.4179/31(023,203), 1.4124/37 (122,212). The crystal structure of pertoldite is based on corner-sharing [GeO 4 ] tetrahedra forming a three-dimensional network similar to that of α-quartz. Pertoldite is named after Zdeněk Pertold (1933–2020), professor of economic geology at the Faculty of Sciences, Charles University in Prague. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (number 2021-074) and the holotype specimen is deposited in the collections in the Department of Mineralogy and Petrology, National Museum in Prague, under the catalogue number P1P 31/2021.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48531196","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":"HT breakdown of Mn-bearing elbaite from the Anjanabonoina pegmatite, Madagascar","authors":"Paolo Ballirano, B. Celata, Henrik Skogby, G. Andreozzi, F. Bosi, Z. Li, Z. Al→, Y. Li, Al","doi":"10.3190/jgeosci.347","DOIUrl":"https://doi.org/10.3190/jgeosci.347","url":null,"abstract":"The thermal behavior of a gem-quality purplish-red Mn-bearing elbaite from the Anjanabonoina pegmatite, Madagascar, with composition","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49103460","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":"Sn-rich tourmaline from the Land’s End granite, SW England","authors":"K. Drivenes","doi":"10.3190/jgeosci.351","DOIUrl":"https://doi.org/10.3190/jgeosci.351","url":null,"abstract":"no Multiple generations and growth stages of tourmaline from a hydrothermal quartz-tourmaline rock from the Land’s End granite, SW England, were investigated by Electron Probe MicroAnalyzer (EPMA) to reveal details of the variation in tourmaline composition with emphasis on the distribution of Sn. Tourmaline shows a large range in chemical composition, mostly on the dravite–schorl solid solution and towards more Fe-rich compositions. Several growth zones have very high Fe levels (> 3.5 apfu ) with a significant amount of Fe 3+ coupled with low Al. The main substitution vectors controlling the major element composition are Fe 2+ Mg –1 and Fe 3+ Al –1 . The Fe–Mg exchange is the main substitution in the earlier growth stages, whereas the Fe–Al substitution becomes more important towards the end of the crystallization sequence. Tin is commonly associated with the high-Fe zones, but all Fe-rich zones do not necessarily have elevated Sn content. Octahedral sites in tourmaline, most likely the Y -site, host Sn through the proposed coupled substitution YZ Sn 4+ + 2 YZ Fe 2+ + 5 YZ Fe 3+ + W O 2– ↔ 2 YZ Mg 2+ + 6 YZ Al 3+ + W OH – . The thin Sn-rich zones, hosting up to 2.53 wt. % SnO 2 , are interpreted to coincide with the onset of cassiterite crystallization, and the lower Sn content in subsequent growth zones reflects the fluid chemistry and Sn solubility in a cassiterite-buffered hydrothermal system. This study demonstrates the suitability of quantitative X-ray mapping in identifying and quantifying minor elements in finely-spaced growth zones.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43453061","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 arising from the international conference TUR2021","authors":"J. Cempírek, F. Bosi, H. Marschall","doi":"10.3190/jgeosci.360","DOIUrl":"https://doi.org/10.3190/jgeosci.360","url":null,"abstract":"1 Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic; jcemp@sci.muni.cz 2 Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy; ferdinando.bosi@uniroma1.it 3 FIERCE (Frankfurt Isotope & Element Research Center), Goethe Universität, Frankfurt am Main, Germany; marschall@em.uni-frankfurt.de","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45047982","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":"Nickel- and Fe3+-rich oxy-dravite from the Artana Mn prospect, Apuan Alps (Tuscany, Italy)","authors":"D. Mauro, C. Biagioni, U. Hålenius, H. Skogby, V. Dottorini, F. Bosi","doi":"10.3190/jgeosci.346","DOIUrl":"https://doi.org/10.3190/jgeosci.346","url":null,"abstract":"Nickel-and Fe 3+ -rich oxy-dravite was identified on a specimen collected in the Artana Mn prospect, Carrara, Apuan Alps, Tuscany, Italy. Oxy-dravite occurs as brownish-orange prismatic crystals, up to 0.3 mm in length, associated with quartz, carbonates, and hematite. Electron microprobe analysis gave (in wt. % – average of 7 spot analyses): SiO 2 35.81, TiO 2 0.41, B 2 O 3(calc) 10.38, Al 2 O 3 29.36, V 2 O 3 0.78, Cr 2 O 3 0.09, Fe 2 O 3 3.32, FeO 0.33, MgO 8.04, CaO 0.39, MnO 0.34, NiO 3.46, ZnO 0.40, Na 2 O 2.84, F 0.29, H 2 O (calc) 3.00, O = F –0.12, total 99.12. The Fe 3+ /Fe tot ratio was calculated based on optical absorp","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43658649","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}