Journal of Geosciences最新文献

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

{"title":"Perspectives on premetamorphic stratabound tourmalinites","authors":"J. Slack","doi":"10.3190/jgeosci.349","DOIUrl":"https://doi.org/10.3190/jgeosci.349","url":null,"abstract":".","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":"42046645","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":"Calcium-rich dravite from the Arignac Gypsum Mine, France: Implications for tourmaline development in a sulfate-rich, highly magnesian meta-evaporite","authors":"B. Dutrow, D. Henry","doi":"10.3190/jgeosci.352","DOIUrl":"https://doi.org/10.3190/jgeosci.352","url":null,"abstract":"Tourmaline occurs in a wide range of compositional environments, but its occurrence in meta-evaporites is less commonly investigated. Highly magnesian ( X Mg = 0.90–0.98), poikiloblastic tourmaline occurs in a sulfate-rich, anhydrite– gypsum-bearing meta-evaporite in the Arignac Gypsum Mine, France and preserves a petrologic record of this unusual geochemical environment. Originally a Triassic evaporite deposit, the sample is interpreted to have undergone high-temperature–low-pressure (HT–LP) metamorphism and subsequently experienced low-grade, highly deformed overprints. Poikiloblastic tourmaline preserves relicts of the HT–LP mineral assemblage, as inclusions of anhydrite, phlogopite, dolomite, tremolite, Cl-rich scapolite (71–85 % marialite component), rutile, zircon, and fluor-apatite. The low-grade deformational overprints are characterized by partial replacement of anhydrite by gypsum, phlogopite by clinochlore, dolomite by talc, and scapolite by mixtures of near end-member albite and K-feldspar with later crosscutting calcite and celestite. Tourmaline develops two textural zones – zone 1 with few mineral inclusions and zone 2 with abundant inclusions and/or complex chemical zoning. The tourmaline","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":"43375573","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":"Ti4+ and Sn4+-bearing tourmalines - pressure control and comparison of synthetic and natural counterparts","authors":"O. Vereshchagin, Bernd Wunder, Ivan A. Baksheev, Franziska D.H. Wilke, N. S. Vlasenko, O. Frank-Kamenetskaya, Ag Li","doi":"10.3190/jgeosci.345","DOIUrl":"https://doi.org/10.3190/jgeosci.345","url":null,"abstract":".","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":"45501425","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 inner architecture of tourmaline crystals, as inferred from the morphology of color zones in thin slices","authors":"P. Rustemeyer","doi":"10.3190/jgeosci.348","DOIUrl":"https://doi.org/10.3190/jgeosci.348","url":null,"abstract":"","PeriodicalId":15957,"journal":{"name":"Journal of Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41611206","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":"Geological interpretation of a seismic reflection profile in the eastern part of the Bohemian Cretaceous Basin","authors":"Z. Skácelová, B. Mlčoch, S. Čech","doi":"10.3190/jgeosci.339","DOIUrl":"https://doi.org/10.3190/jgeosci.339","url":null,"abstract":"A seismic reflection profile was realized in the eastern part of the Bohemian Cretaceous Basin in the years 2013–2015. Seismic research was supported by a detailed gravity and geoelectric survey. The profile crossed three significant hydrogeological structures or districts: Vysoké Mýto, Ústí and Kyšperk synclines. Interpretation of geophysical data enabled a determination of the Cretaceous sediments with a thickness of up to 250 m and Permian sediments even with a thickness of 2000 m. The seismic reflectors and gravity effect, together with the boreholes and geological mapping, were used to compile the uncovered geological map.","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":"48854353","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":"Ar-Ar Geochronology and Sr-Nd-Pb-O Isotopic Systematics of the Post-collisional Volcanic Rocks from the Karapınar-Karacadağ Area (Central Anatolia, Turkey): An Alternative Model for Orogenic Geochemical Signature in Sodic Alkali Basalts","authors":"Gülin GENÇOG˘LU Korkmaz, H. Kurt, Kürşad Asan, Matthew Leybourne","doi":"10.3190/jgeosci.343","DOIUrl":"https://doi.org/10.3190/jgeosci.343","url":null,"abstract":"The Plio–Quaternary post-collisional volcanism in the Karapınar area is represented by two occurrences: (1) Karacadağ Volcanic Complex (KCVC) and (2) Karapınar Volcanic Field (KPVF). The investigated volcanic units are the southwes - tern part of the Neogene to Quaternary Cappadocia Volcanic Province (CVP) in Central Anatolia. The CVP generally displays calc–alkaline affinity in the Late Miocene to Pliocene rocks, but both calc-alkaline and sodic alkaline affinity in the Plio–Quaternary rocks, all of which have an orogenic geochemical signature. Such a volcanic activity contradicts the Western and Eastern Anatolian volcanism characterized by anorogenic OIB-like sodic alkaline volcanic rocks postdating early orogenic calc–alkaline ones. We hypothesize that such temporal and geochemical variations in the investigated rocks result from crustal contamination and present major and trace element chemistry and Sr–Nd–Pb–O isotope geochemistry, coupled with 40 Ar/ 39 Ar geochronology data to restrict the genesis and evolution of the rocks. The Neogene Karacadağ volcanic rocks are represented by lava flows, domes and their pyroclastic equivalents constituting a stratovolcano, and dated by new 40 Ar/ 39 Ar ages of 5.65 to 5.43 Ma. They are mainly composed of andesitic, rarely basaltic, dacitic and trachytic rocks and have a calc–alkaline character. Constituting a monogenetic volcanic field, the Quaternary Karapınar volcanic rocks are typically formed by cinder cones, maars and associated lavas, including xenoliths and xenocrysts plucked from the Karacadağ rocks. They comprise basaltic to andesitic rocks with a transitional affinity, from sodic alkaline to calc–alkaline. Both the Karacadağ and Karapınar volcanic rocks display incompatible trace element patterns rather characteristic for orogenic volcanic rocks. The Sr, Nd and Pb isotopic systematics of both units show a relatively narrow range, but their δ 18 O values are markedly different. The Karacadag volcanic rocks have δ 18 O values ranging from 7.5 to 8.9 ‰, resembling those of subduction-related basalts, but the Karapınar volcanics have δ 18 O ratios between 5.7 and 6.5 ‰ corresponding to OIB-like rocks. Additionally, δ 18 O values and 87 Sr/ 86 Sr ratios correlate positively with SiO 2 in the rocks, indicating that contamination played an important role during differentiation processes. All the data obtained suggest that the Karacadağ basaltic rocks stemmed from a subduction-modified lithospheric mantle source. On the other hand, the origin of the Karapınar basaltic rocks can be explained in terms of OIB-like melts contaminated with the Karacadağ volcanic rocks to gain orogenic geochemical signature, which may be an alternative model for the origin of the CVP sodic alkali basalts.","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":"49058714","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":"Titanium-oxide activity during the formation of gold-bearing quartz veins: evidence for closed system behavior","authors":"K. Pacak, J. Zacharias, M. Němec","doi":"10.3190/jgeosci.340","DOIUrl":"https://doi.org/10.3190/jgeosci.340","url":null,"abstract":"Titanium contents of both vein and magmatic quartz from five Bohemian gold deposits with known P–T history were used to calculate/discuss the titanium oxide activities (a TiO 2 ) of natural quartz formed in the absence of Ti-buffering phases at 250–550 °C and 0.1–4 kbar. Data suggest significant variations in a TiO 2 during vein quartz formation, due to variation of P, T and growth rate. Negative correlation between a TiO 2 and quartz formation temperature was documented for intrusion-related gold deposits, implying quartz precipitation under closed-system conditions (i.e., without substantial equilibration of the ascending fluid with surrounding rocks). We propose a relationship for quantifying disequilibrium quartz formation that can be readily applied to quartz with known P–T history. The relationship was tested on natural samples exhibiting both rapid and slow","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":"46189182","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":"Michalskiite, Cu2+Mg3Fe3+3.33(VO4)6, an Mg analogue of lyonsite, from the Ronneburg uranium deposit, Thuringia, Germany","authors":"A. Kampf, J. Plášil, R. Škoda, J. Čejka","doi":"10.3190/jgeosci.341","DOIUrl":"https://doi.org/10.3190/jgeosci.341","url":null,"abstract":"","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":"42111887","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}