European Journal of Mineralogy最新文献

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Dutrowite, Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O, a new mineral from the Apuan Alps (Tuscany, Italy): the first member of the tourmaline supergroup with Ti as a species-forming chemical constituent Dutrowite,Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O,一种来自阿普安阿尔卑斯山脉(意大利托斯卡纳)的新矿物:电气石超群中第一个以Ti为物种形成化学成分的成员
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-02-10 DOI: 10.5194/ejm-35-81-2023
C. Biagioni, F. Bosi, D. Mauro, H. Skogby, A. Dini, F. Zaccarini
{"title":"Dutrowite, Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O, a new mineral from the Apuan Alps (Tuscany, Italy): the first member of the tourmaline supergroup with Ti as a species-forming chemical constituent","authors":"C. Biagioni, F. Bosi, D. Mauro, H. Skogby, A. Dini, F. Zaccarini","doi":"10.5194/ejm-35-81-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-81-2023","url":null,"abstract":"Abstract. The new tourmaline supergroup mineral dutrowite,\u0000Na(Fe2.52+Ti0.5)Al6(Si6O18)(BO3)3(OH)3O,\u0000has been discovered in an outcrop of a Permian metarhyolite near the hamlet\u0000of Fornovolasco, Apuan Alps, Tuscany, Italy. It occurs as chemically\u0000homogeneous domains, up to 0.5 mm, brown in colour, with a light-brown streak\u0000and a vitreous lustre, within anhedral to subhedral prismatic crystals, up\u0000to 1 mm in size, closely associated with Fe-rich oxy-dravite. Dutrowite is\u0000trigonal, space group R3m, with a=15.9864(8), c=7.2187(4) Å, V=1597.68(18) Å3, and Z=3. The crystal structure was refined to\u0000R1=0.0257 for 1095 unique reflections with Fo>4σ (Fo) and 94 refined parameters. Electron microprobe analysis,\u0000coupled with Mössbauer spectroscopy, resulted in the empirical\u0000structural formula X(Na0.81Ca0.20K0.01)Σ1.02 Y(Fe1.252+Mg0.76Ti0.56Al0.42)Σ3.00 Z(Al4.71Fe0.273+V0.023+Mg0.82Fe0.182+)Σ6.00 T[(Si5.82Al0.18)Σ6.00O18]\u0000(BO3)3O(3)(OH)3O(1)[O0.59(OH)0.41]Σ1.00, which was recast in the\u0000empirical ordered formula, required for classification purposes:\u0000X(Na0.81Ca0.20K0.01)Σ1.02 Y(Fe1.432+Mg1.00Ti0.56)Σ3.00 Z(Al5.13Fe0.273+V0.023+Mg0.58)Σ6.00 T[(Si5.82Al0.18)Σ6.00O18]\u0000(BO3)3V(OH)3 W[O0.59(OH)0.41]Σ1.00. Dutrowite is an\u0000oxy-species belonging to the alkali group of the tourmaline supergroup.\u0000Titanium is hosted in octahedral coordination, and its incorporation is\u0000probably due to the substitution 2Al3+ = Ti4+ + (Fe,Mg)2+. Its occurrence seems to be related to late-stage\u0000high-T/low-P replacement of “biotite” during the\u0000late-magmatic/hydrothermal evolution of the Permian metarhyolite.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45306201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 71 国际矿物协会新矿物、命名法和分类委员会-通讯71
3区 地球科学
European Journal of Mineralogy Pub Date : 2023-02-06 DOI: 10.5194/ejm-35-75-2023
Pete Williams, Frédéric Hatert, Marco Pasero, Stuart Mills
{"title":"IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 71","authors":"Pete Williams, Frédéric Hatert, Marco Pasero, Stuart Mills","doi":"10.5194/ejm-35-75-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-75-2023","url":null,"abstract":"","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136372236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Bobtraillite from Gejiu hyperagpaitic nepheline syenite, southwestern China: new occurrence and crystal structure 个旧超白霞石正长岩中Bobtrallite的新产状及晶体结构
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-01-31 DOI: 10.5194/ejm-35-65-2023
Yanjuan Wang, F. Nestola, Z. Hou, X. Gu, G. Dong, Zhusen Yang, Guang Fan, Zhibin Xiao, Kai Qu
{"title":"Bobtraillite from Gejiu hyperagpaitic nepheline syenite, southwestern China: new occurrence and crystal structure","authors":"Yanjuan Wang, F. Nestola, Z. Hou, X. Gu, G. Dong, Zhusen Yang, Guang Fan, Zhibin Xiao, Kai Qu","doi":"10.5194/ejm-35-65-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-65-2023","url":null,"abstract":"Abstract. A second occurrence of bobtraillite is described from the\u0000Gejiu nepheline syenite, southwestern China. The extremely rare and complex\u0000boron-bearing zirconium silicate is associated with albite, orthoclase,\u0000jadeite, fluorite, andradite, titanite, as well as other REE and\u0000zirconium-bearing minerals, catapleiite, moxuanxueite, låvenite,\u0000eudialyte, britholite-(Ce), and calcioancylite-(La). The EMP and LA-ICP-MS\u0000analyses of the studied material give an empirical formula:\u0000(Na9.70Li0.42K0.08□1.80)Σ12.00(Sr10.61Ca1.14Fe0.07□0.18)Σ12.00(Zr12.87Ti0.53Nb0.31REE0.08Y0.06U0.02Th0.01□0.12)Σ14.00(Si42.41B5.59Al0.02)Σ48.02O132(OH)12 ⚫ 12H2O. Bobtraillite is trigonal,\u0000with space group P3¯c1, a=19.6977(6), c=9.9770(3) Å, V=3352.4(2) Å3, Z=1. Single-crystal structure refinement revealed\u0000that all sodium occupies the Na(1) and Na(2) sites; the site occupancy of\u0000these two positions is 0.835(18) and 0.15(2), respectively, suggesting that\u0000Na(1) site is Na dominant, while Na(2) is a vacancy-dominant site. The\u0000[8]-coordinated site has been assigned to Sr and Ca, with free\u0000occupancy factors, 0.874(10) and 0.126(10), respectively. These new data\u0000indicate that the ideal formula of bobtraillite could be written as\u0000(Na,□)12(□,Na)12Sr12Zr14(Si3O9)10[Si2BO7(OH)2]6 ⚫ 12H2O.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48376475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Appearance, study and a possible correction for boron: a phenomenon in ultra-soft X-ray measurements using a synthetic multilayer crystal and the EPMA 硼的外观、研究和可能的校正:使用合成多层晶体和EPMA进行超软x射线测量中的一种现象
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-01-25 DOI: 10.5194/ejm-35-59-2023
F. Wilke
{"title":"Appearance, study and a possible correction for boron: a phenomenon in ultra-soft X-ray measurements using a synthetic multilayer crystal and the EPMA","authors":"F. Wilke","doi":"10.5194/ejm-35-59-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-59-2023","url":null,"abstract":"Abstract. When measuring boron (B) in tourmalines calibrated with schorl, no deviations in\u0000the peak intensities could be detected with a proven analysis protocol and\u0000using the Mo/B4C multilayer crystal LDEB. It is only when boron is detected\u0000in natural and experimental samples, some with significantly lower boron\u0000concentrations than in tourmalines, that irregularities in the analysis\u0000become visible. This phenomenon is known but has not been analytically\u0000investigated so far. Using four natural and artificial solids with boron\u0000concentrations from 0.035 wt %–3.14 wt % B, an apparent linear trend line was\u0000drawn. The intersect of that trend line with the y axis represents the\u0000detection limit of boron, which is of about 0.25 wt % B. The discrepancy\u0000between the apparent and the true value trend lines at boron concentrations of\u00000.25 wt %–2.1 wt % B shows that a correction is necessary. At higher boron\u0000concentrations, the discrepancy between the apparent and true value\u0000trend lines is within the uncertainty of electron microprobe analysis (EPMA) and disappears\u0000completely up to boron concentrations of about 3 wt %.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46106627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Shear properties of MgO inferred using neural networks 利用神经网络推断MgO的剪切特性
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-01-17 DOI: 10.5194/ejm-35-45-2023
Ashim Rijal, L. Cobden, J. Trampert, H. Marquardt, J. Jackson
{"title":"Shear properties of MgO inferred using neural networks","authors":"Ashim Rijal, L. Cobden, J. Trampert, H. Marquardt, J. Jackson","doi":"10.5194/ejm-35-45-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-45-2023","url":null,"abstract":"Abstract. Shear properties of mantle minerals are vital for interpreting seismic shear wave speeds and therefore inferring the composition and dynamics of a planetary interior. Shear wave speed and elastic tensor components, from which the shear modulus can be computed, are usually measured in the laboratory mimicking the Earth's (or a planet's) internal pressure and temperature conditions. A functional form that relates the shear modulus to pressure (and temperature) is fitted to the measurements and used to interpolate within and extrapolate beyond the range covered by the data. Assuming a functional form provides prior information, and the constraints on the predicted shear modulus and its uncertainties might depend largely on the assumed prior rather than the data. In the present study, we propose a data-driven approach in which we train a neural network to learn the relationship between the pressure, temperature and shear modulus from the experimental data without prescribing a functional form a priori. We present an application to MgO, but the same approach works for any other mineral if there are sufficient data to train a neural network. At low pressures, the shear modulus of MgO is well-constrained by the data. However, our results show that different experimental results are inconsistent even at room temperature, seen as multiple peaks and diverging trends in probability density functions predicted by the network. Furthermore, although an explicit finite-strain equation mostly agrees with the likelihood predicted by the neural network, there are regions where it diverges from the range given by the networks. In those regions, it is the prior assumption of the form of the equation that provides constraints on the shear modulus regardless of how the Earth behaves (or data behave). In situations where realistic uncertainties are not reported, one can become overconfident when interpreting seismic models based on those defined equations of state. In contrast, the trained neural network provides a reasonable approximation to experimental data and quantifies the uncertainty from experimental errors, interpolation uncertainty, data sparsity and inconsistencies from different experiments.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45618885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Compositional variation and zoning of epidote supergroup minerals in the Campi Flegrei geothermal field, Naples, Italy 意大利那不勒斯Campi Flegrei地热田绿石超群矿物组成变化及分带特征
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-01-06 DOI: 10.5194/ejm-35-25-2023
H. Belkin, B. De Vivo
{"title":"Compositional variation and zoning of epidote supergroup minerals in the Campi Flegrei geothermal field, Naples, Italy","authors":"H. Belkin, B. De Vivo","doi":"10.5194/ejm-35-25-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-25-2023","url":null,"abstract":"Abstract. Authigenic epidote supergroups are an abundant accessory mineral in the\u0000calcium–aluminum silicate and thermometamorphic hydrothermal zones of the\u0000Campi Flegrei (Phlegraean Fields) geothermal field located west of Naples,\u0000Italy. Geothermal exploration for high-enthalpy fluid produced drill core\u0000and cuttings to ∼ 3 km depth in the Mofete (MF1, MF2, MF5) and\u0000San Vito (SV1, SV3) wells, where measured down-hole temperatures of\u0000epidote-bearing samples range from 270–350 ∘C and from\u0000285–390 ∘C for the Mofete and San Vito areas, respectively. Two\u0000epidote group (epidote, clinozoisite), some rare earth element\u0000(REE)-bearing, and two allanite group (allanite-(Ce), ferriallanite-(Ce))\u0000minerals were identified by electron microprobe. The allanite group is light\u0000rare earth element (LREE, La–Gd) enriched, Ce dominant, with REE + Y that\u0000varies from 30.59 wt %–14.32 wt %. Complex compositional variation such as\u0000oscillatory, sector, and complex (mixed) zoning is a ubiquitous feature\u0000observed in the epidote group, which occurs as veins, in vugs, as various\u0000size masses, and as isolated single crystals. Compositional zoning is caused\u0000by variable Fe ↔ Al3+ substitution and XFe [(Fe3+) / (Fe3++ Al)] ranges from 0.06–0.33 (Fe3+=0.185–0.967 apfu). XFe tends to decrease with increasing temperature\u0000in the Mofete wells, but its distribution is more complex in the San Vito\u0000wells, which records recent fault displacement. The variety and complexity\u0000of the epidote supergroup zoning suggest rapid fluid composition and/or\u0000intensive parameter fluctuations in the local hydrothermal system.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71223644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Reactive interaction between migmatite-related melt and mafic rocks: clues from the Variscan lower crust of Palmi (southwestern Calabria, Italy) 混合岩相关熔体和镁铁质岩石之间的反应相互作用:来自帕尔米(意大利卡拉布里亚西南部)华力西下地壳的线索
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2023-01-04 DOI: 10.5194/ejm-35-1-2023
M. Renna
{"title":"Reactive interaction between migmatite-related melt and mafic rocks: clues from the Variscan lower crust of Palmi (southwestern Calabria, Italy)","authors":"M. Renna","doi":"10.5194/ejm-35-1-2023","DOIUrl":"https://doi.org/10.5194/ejm-35-1-2023","url":null,"abstract":"Abstract. In the Variscan lower–intermediate crust exposed in the Palmi area (southwestern\u0000Calabria, Italy), amphibolites occur as foliated, decimeter-thick layers\u0000within migmatitic paragneiss and as a decametric main body adjacent to the\u0000migmatites. The main body is mostly fine-grained and weakly to moderately\u0000foliated; unfoliated medium-grained portions rarely occur. Amphibolites are\u0000mainly composed of plagioclase (An80−91) frequently developing triple\u0000junctions, amphibole consisting of cummingtonite rimmed by hornblende and\u0000variable amounts of biotite. Minor quartz is present in amphibolite layers\u0000within paragneiss. Accessory allanite occurs in amphibolite layers within\u0000migmatites and in foliated, fine-grained portions from the main body. This\u0000study mainly aims to achieve information about the effects triggered by the\u0000migration of migmatite-related melts into associated mafic rocks and its\u0000role in the re-distribution of major and trace elements out of the anatectic\u0000source. On the basis of whole-rock major- and trace-element compositions, the\u0000protolith of amphibolite is recognized as of cumulus origin, likely derived\u0000from basic melt emplaced in the framework of the late-Variscan lithospheric\u0000extension. The rocks experienced high-temperature subsolidus\u0000re-equilibration (∼800 ∘C) in conjunction with the\u0000development of amphibole. The origin of amphibole is attributed to a coupled\u0000dissolution–precipitation process related to the reaction between migrating\u0000SiO2-rich hydrous melt and precursor orthopyroxene (± plagioclase). Reactive melt migration also caused the crystallization of\u0000biotite ± allanite ± quartz ± plagioclase. SiO2-rich\u0000hydrous melt had REE (rare earth element) compositions similar to late-Variscan peraluminous\u0000granites and could have been derived by partial melting of metasediments\u0000akin to neighboring migmatitic paragneisses. Both whole-rock and amphibole analyses reveal a decrease in Mg# (Mg/(Mg+Fe2+)) from\u0000amphibolite layers within paragneiss to fine- and medium-grained rocks of\u0000the main body. Hornblende shows an increase in SiO2 and a decrease in\u0000Al2O3 and K2O with increasing Mg#. Amphibolites\u0000interlayered with paragneiss have higher K2O, Rb, Ba, Th, U and Zr\u0000relative to those from the main body. Furthermore, amphibole from\u0000amphibolites interlayered with paragneiss is distinct for relatively high\u0000Rb, Ba, MREE (middle rare earth element) and HREE (heavy rare earth element) concentrations. Within the main body, foliated,\u0000fine-grained rock has both the whole rock and amphibole enriched in Rb and Ba\u0000and high Zr bulk-rock contents. Whole-rock and mineral chemistry\u0000heterogeneity most likely reflects (i) variation of the composition of the\u0000melt during its reactive migration, in response to dissolution of\u0000pre-existing minerals and crystallization of new phases, and (ii) variable\u0000modification of the original compositions. Foliated and fine-grained\u0000amphibolites record the strongest modification, thereby suggesting that they\u0000represent permeabl","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49444530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Molecular overtones and two-phonon combination bands in the near-infrared spectra of talc, brucite and lizardite 滑石、水镁石和锂辉石近红外光谱中的分子泛音和两个声子组合带
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2022-12-14 DOI: 10.5194/ejm-34-627-2022
E. Balan, L. Paulatto, Qianyu Deng, K. Béneut, M. Guillaumet, B. Baptiste
{"title":"Molecular overtones and two-phonon combination bands in the near-infrared spectra of talc, brucite and lizardite","authors":"E. Balan, L. Paulatto, Qianyu Deng, K. Béneut, M. Guillaumet, B. Baptiste","doi":"10.5194/ejm-34-627-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-627-2022","url":null,"abstract":"Abstract. The near-infrared (NIR) spectra of hydrous minerals display absorption bands\u0000involving multiple excitations of vibrational modes. They usually involve OH\u0000stretching modes, but their interpretation is not straightforward due to the\u0000combined effects of bond anharmonicity and vibrational coupling. In the\u0000present study, the mid-infrared (MIR) and near-infrared spectra of\u0000well-ordered samples of trioctahedral layered hydrous minerals, talc,\u0000brucite and lizardite, have been measured on a spectral range extending\u0000from the fundamental vibrational modes to the second OH stretching\u0000overtones. The bands corresponding to molecular overtones are interpreted\u0000using an effective approach allowing us to infer the anharmonicity and coupling\u0000parameters controlling the OH stretching frequencies from spectroscopic data.\u0000They follow the usual relation between transition energy and quantum number\u0000of the excited state, which facilitates the comparison of NIR and MIR\u0000spectra. The results support the assignment of the main overtone bands to\u0000specific environments of OH groups and bring new constraints for the\u0000identification of the vibrational bands related to Fe and Al substitutions\u0000at octahedral sites in serpentines. The two-phonon absorption bands are\u0000theoretically analyzed at the density functional theory level by computing\u0000the absorption arising from the self-energy of the IR-active vibrational\u0000modes. The characteristics of the two-phonon OH stretching continuum between\u00007300 and 7400 cm−1 and of the combination bands between 4000 and 4800 cm−1 are related to the specificities of the one-phonon and two-phonon\u0000densities of states of the three minerals.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46464872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Iron oxidation state in serpentines and magnesian chlorites of subduction-related rocks 俯冲相关岩石的蛇纹岩和镁绿泥石中的铁氧化态
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2022-12-14 DOI: 10.5194/ejm-34-645-2022
B. Reynard, C. Fellah, C. McCammon
{"title":"Iron oxidation state in serpentines and magnesian chlorites of subduction-related rocks","authors":"B. Reynard, C. Fellah, C. McCammon","doi":"10.5194/ejm-34-645-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-645-2022","url":null,"abstract":"Abstract. The ferric iron content in hydrothermally altered ultrabasic rocks and their major minerals, serpentines and Mg-chlorites, is important for establishing the oxidation state budget from oceanic ridges to subduction zones, in carbonaceous chondrites, and for modeling phase equilibria. A compilation of literature Mössbauer spectroscopic data on serpentines and magnesian chlorites from high-pressure ophiolites yields much lower ferric-to-total-iron ratios (Fe3+ / Fetotal) than those obtained on similar samples by X-ray absorption near-edge spectroscopy (XANES), leading to contradictory estimates of the ferric iron budget of subduction zones. New Mössbauer analysis of antigorite and Mg-chlorite samples from suites of high-pressure ophiolitic terrains of various Phanerozoic ages confirms the low and homogeneous values previously obtained by this technique, while lizardite inherited from oceanic hydrothermal alteration is ferric iron rich. We argue that XANES values may be biased by photo-oxidation when samples have a high Mg content, which is the case for serpentines and chlorites from subduction zones. Photo-oxidation is less important in Fe-poor phyllosilicates of the mica and talc families and does not affect the Fe-rich serpentines (greenalite, cronstedtite) of meteorites or Fe-rich terrestrial phyllosilicates. Mössbauer Fe3+ / Fetotal ratios of serpentine confirm the occurrence of a major redox change at the lizardite–antigorite transition near 300–400 ∘C rather than at the dehydration of antigorite at 500–650 ∘C in serpentinites from high-pressure ophiolites.","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41365226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
ICDP Oman Drilling Project: varitextured gabbros from the dike–gabbro transition within drill core GT3A ICDP阿曼钻探项目:GT3A岩芯内岩脉-辉长岩过渡带的变结构辉长岩
IF 2.1 3区 地球科学
European Journal of Mineralogy Pub Date : 2022-12-12 DOI: 10.5194/ejm-34-603-2022
Artur Engelhardt, J. Koepke, Chao Zhang, D. Garbe‐Schönberg, A. Jesus
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