Journal of Geosciences最新文献

{"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}

{"title":"Crystal chemistry and evolution of tourmaline in tourmalinites from Zlatá Idka, Slovakia","authors":"P. Bačík, D. Ozdín, P. Uher, M. Chovan, Al□Mg, AlOMg, Mg, FeCaAl","doi":"10.3190/jgeosci.350","DOIUrl":"https://doi.org/10.3190/jgeosci.350","url":null,"abstract":"Tourmalinites occur in early-Paleozoic metamorphic rocks of the Gemeric Unit near Zlatá Idka village, Western Car-pathians, eastern Slovakia. Tourmaline compositions, analyzed with the electron microprobe, include a wide range of tourmaline species. Tourmaline in tourmalinites from Zlatá Idka is compositionally variable, with the dominant substitution Mg–Fe 2+ consistent with prevalent schorl–dravite compositions and their fluor-and oxy-dominant counterparts – fluor-schorl, fluor-dravite, oxy-schorl and oxy-dravite. Portions of tourmaline are enriched in Ca in the form of the fluor-uvite and magnesio-lucchesiite components. A subset of the compositions has Ti > 0.25 atoms per formula unit ( apfu ) and corresponds to the hypothetical “magnesio-dutrowite”, Mg-dominant analogue of dutrowite. In addition, some of the tourmalines are X -site vacant and classified as foitite. The crystal chemistry of tourmaline is complex and influenced by several exchange mechanisms, including Mg(Fe) –1 , Al□(Mg,Fe) –1 Na –1 , AlO(Mg,Fe) –1 (OH) –1 (Mg,Fe)CaAl –1 Na –1 , MgCaOAl –1 □ –1 (OH) –1 , Ti 0.5 O(Fe,Mg) –0.5 (OH) –1 and TiMg(Al) –2 substitutions. In general, tourmalines in all samples usually have oscillatory-zoned dravitic cores and schorlitic rims (Tur I). However, in ZLT-4 and ZLT-6 samples, some crystals have secondary Mg-dominant and Ca-enriched overgrowths (Tur II), partially replacing Tur I. Tourmalinites were most likely produced by regional or contact metasomatic processes, likely due to the intrusion of the Permian Poproč granitic massif. Origin of tourmalinites likely results from the flow of late-magmatic to early post-magmatic B,F-rich fluids from the granite intrusion into adjacent metamorphic rocks. The tourmaline crystallization and its resulting chemical composition were controlled by both the metapelitic host rock and the granitic intrusion; the Mg-rich cores of the Tur I are most likely compositionally related to the metapelitic host rock, whereas later schorlitic to foititic compositions in rims suggest origin due to the intrusion-triggered fluid flow. The significant changes and oscillations of tourmaline zon - ing imply a dynamic, unstable fluid regime. The late Ca-rich Tur II could result from subsequent metasomatic processes associated with the alteration of host-rock minerals.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44707496","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":"Schorl-1A from Langesundsfjord (Norway)","authors":"F. Câmara, F. Bosi, H. Skogby, U. Hålenius, B. Celata, M. Ciriotti","doi":"10.3190/jgeosci.344","DOIUrl":"https://doi.org/10.3190/jgeosci.344","url":null,"abstract":"A crystal fragment of schorl from Langesundsfjord (Norway), showing a zonation with a biaxial optic behavior in the rim, was studied by electron microprobe analysis, single-crystal X-ray diffraction, Mössbauer, infrared and optical absorption spectroscopy and optical measurements. Measured 2 V x is 15.6°. We concluded that biaxial character of the sample is not due to internal stress because it cannot be removed by heating and cooling. Diffraction data were refined with a standard R 3 m space group model, with a = 16.0013(2) Å, c = 7.2263(1) Å, and with a non-conventional triclinic R 1 space-group model keeping the same hexagonal triple cell ( a = 16.0093(5) Å, b = 16.0042(5) Å, c = 7.2328(2) Å, α = 90.008(3)°, β = 89.856(3)°, γ = 119.90(9)°), yielded R all = 1.75% (3136 unique reflections) vs. R all = 2.","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44121888","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}