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.
Capillitas是阿根廷的一个浅成热液脉型矿床，以其矿物学多样性而闻名，有超过一百二十种已描述的矿物，包括五个新种，并存在带状和钟乳石菱锰矿。Stalacites以不同尺寸的单个或组合圆柱体出现，长度从几厘米到1.36米，直径可达8厘米。它们的横截面可能表现出不同的方面：从简单的同心条纹到更复杂的纹理，而它们的外表面可以是光滑的，有起伏或扑克芯片状纹理。钟乳石的颜色从白色到覆盆子粉色不等，边缘偶尔会有棕色条纹，对应于一种名为“capillitite”的各种菱锰矿。MnO的含量范围为27.50至61.71重量%，因为它可以被CaO、FeO、ZnO和MgO显著取代。这种矿物所显示的各种深浅的粉红色和棕色反映了置换作用。粉红色样品中的不同取代对晶胞参数的影响很小，而在棕色品种中，它们的大小明显较小，粉红色菱锰矿（n=24）的平均值为：a 4.776Å，c 15.690Å，细胞体积为310.3Å3，而“capillite”晶胞参数（n=7）为：a=4.739，c=15.558，晶胞体积为302.6Å3。从流体包裹体数据中获得的25 de Mayo脉带状菱锰矿的形成条件表明，温度为145°至150°C，盐度高达4 wt.%NaCl（eq）。钟乳石的形成是通过超热液渗透到一个短暂充满蒸汽的孤立空腔中来解释的，超热液中含有Mn和碳酸氢盐。
{"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}
P. Jakubová, J. Kotková, R. Wirth, R. Škoda, J. Haifler
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.
{"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}
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.
{"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}
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.
这种新矿物是在捷克共和国赫拉德茨Králové省Trutnov附近的Radvanice废弃煤矿燃烧的废料堆中发现的。垃圾场火灾是1980年以前自发发生的，没有人为的物质沉积在那里。作为合成的三角形α-GeO - 2的天然类似物的橄榄岩的测定是基于其化学成分、x射线粉末衍射数据和拉曼光谱。橄榄石以白色至棕色聚集体的形式出现，类似于棉花簇，大小可达1毫米，由1 μm厚、1毫米长的针状晶体组成。单个晶体被扭曲，类似于纺织纤维。含Cl和F的高温(400-500℃)气体在燃烧的煤矿排土场地表下40-60 cm深度直接结晶形成橄榄岩。它与方铅矿、辉锑矿、铋锑矿、绿钛矿和铋的多组分聚集体一起在粉砂岩片上形成一层薄而精致的外壳。理想的橄榄岩配方，geo2，需要100wt . %的geo2。锗部分被二氧化硅取代(2.33-5.67 wt. % sio2)， Ge 1 Si -1取代的程度限制在0.03-0.09 apfu Si，经验公式范围为(Ge 0.91-0.97 Si 0.03-0.09) Σ1.00 o2。橄榄岩呈三角形，p3121或p3221, a = 4.980(5) Å， c = 5.644(4) Å， V = 121.2(2) Å 3, Z = 3。粉末x射线衍射图的最强反射[d (Å)/I (hkl)]分别为: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)。橄榄石的晶体结构以棱角共享的[geo4]四面体为基础，形成类似α-石英的三维网状结构。Pertoldite以布拉格查尔斯大学理学院经济地质学教授zdenk Pertold(1933-2020)的名字命名。该矿物及其名称已得到国际矿物学协会新矿物、命名法和分类委员会(编号2021-074)的批准，全型标本存放在布拉格国家博物馆矿物学和岩石学部的收藏中，目录编号为P1P 31/2021。
{"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}
Paolo Ballirano, B. Celata, Henrik Skogby, G. Andreozzi, F. Bosi, Z. Li, Z. Al→, Y. Li, Al
The thermal behavior of a gem-quality purplish-red Mn-bearing elbaite from the Anjanabonoina pegmatite, Madagascar, with composition
马达加斯加Anjabonoina伟晶岩中一种宝石级紫红色含锰elbaite的热行为
{"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}
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.
利用电子探针显微分析仪(EPMA)研究了英国西南部Land 's End花岗岩热液石英-电气石岩石中电气石的多代和生长阶段，揭示了电气石组成变化的细节，重点研究了锡的分布。电气石的化学成分变化很大，主要是由原石-学校固溶体组成，并向富铁成分方向发展。一些生长带具有非常高的铁含量(> 3.5 apfu)，大量的fe3 +与低Al相结合。控制主要元素组成的主要取代载体是fe2 + Mg -1和fe3 + Al -1。Fe-Mg交换是早期生长阶段的主要取代，而Fe-Al取代在结晶序列的末尾变得更加重要。锡通常与高铁带有关，但并非所有富铁带都必然有高锡含量。电气石中的八面体位置，最有可能是Y -位置，通过提出的耦合取代YZ Sn 4+ + 2yz Fe 2+ + 5yz Fe 3+ + wo2 -↔2yz Mg 2+ + 6yz Al 3+ + woh -来承载Sn。薄的富锡带(含sno2达2.53 wt. %)与锡石结晶的开始一致，随后生长带中较低的锡含量反映了锡石缓冲热液系统中的流体化学和锡溶解度。该研究证明了定量x射线作图在细间距生长带中识别和定量微量元素的适用性。
{"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}
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
{"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}
D. Mauro, C. Biagioni, U. Hålenius, H. Skogby, V. Dottorini, F. Bosi
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
{"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}
P. Bačík, D. Ozdín, P. Uher, M. Chovan, Al□Mg, AlOMg, Mg, FeCaAl
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.
{"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}
F. Câmara, F. Bosi, H. Skogby, U. Hålenius, B. Celata, M. Ciriotti
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.
{"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}
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