Monohydrocalcite (CaCO3·H2O) is a mineral rarely found in natural environments. Here we report finding of this mineral in the composition of the microbialites in Laguna de los Cisnes (Isla Grande, Chile), a saline alkaline lake with high Mg/Ca ratio. We have made a detailed structural and mineralogical description of these microbialites with the use of light and scanning electron microscopy, infrared spectroscopy and X-ray analysis. The predominantly carbonate composition of microbialites was revealed. Carbonates were represented mainly by high-magnesium calcites and monohydrocalcite. Calcite and aragonite were found in minor quantities. In addition, a small amount of silicates and amorphous hydromagnesite were found. The yellowish-brown surface layer of microbialites consists of numerous crystals within a mineralized exopolysaccharide (EPS) matrix. A large number of unicellular and filamentous algae, as well as areas of released EPS, are also seen here. Below is a slimy green layer. This layer is not mineralized, it represents an "algal-bacterial mat" consisting of algae, cyanobacteria, and diatoms developed in EPS. Chisel-shaped crystals of monohydrocalcite and its amorphous spherical precursors are numerous in these upper layers. The deeper layers are mineralized, they consist predominantly of Mg-carbonates with varying degrees of Mg. Algae and cyanobacteria are decomposed or fossilized there. Thus, monohydrocalcite occurs in the composition of the microbialites being one of the main mineral components. As in other lacustrine localities it is formed in the presence of algae and cyanobacteria. To our knowledge this is the first report on the discovery of monohydrocalcite in South America.
{"title":"Formation of Monohydrocalcite in the Microbialites from Laguna de Los Cisnes (Isla Grande de Tierra del Fuego, Chile)","authors":"L. Zaytseva, O. Samylina, A. Prokin","doi":"10.3390/IECMS2021-09340","DOIUrl":"https://doi.org/10.3390/IECMS2021-09340","url":null,"abstract":"Monohydrocalcite (CaCO3·H2O) is a mineral rarely found in natural environments. Here we report finding of this mineral in the composition of the microbialites in Laguna de los Cisnes (Isla Grande, Chile), a saline alkaline lake with high Mg/Ca ratio. We have made a detailed structural and mineralogical description of these microbialites with the use of light and scanning electron microscopy, infrared spectroscopy and X-ray analysis. The predominantly carbonate composition of microbialites was revealed. Carbonates were represented mainly by high-magnesium calcites and monohydrocalcite. Calcite and aragonite were found in minor quantities. In addition, a small amount of silicates and amorphous hydromagnesite were found. \u0000The yellowish-brown surface layer of microbialites consists of numerous crystals within a mineralized exopolysaccharide (EPS) matrix. A large number of unicellular and filamentous algae, as well as areas of released EPS, are also seen here. Below is a slimy green layer. This layer is not mineralized, it represents an \"algal-bacterial mat\" consisting of algae, cyanobacteria, and diatoms developed in EPS. Chisel-shaped crystals of monohydrocalcite and its amorphous spherical precursors are numerous in these upper layers. The deeper layers are mineralized, they consist predominantly of Mg-carbonates with varying degrees of Mg. Algae and cyanobacteria are decomposed or fossilized there. \u0000Thus, monohydrocalcite occurs in the composition of the microbialites being one of the main mineral components. As in other lacustrine localities it is formed in the presence of algae and cyanobacteria. To our knowledge this is the first report on the discovery of monohydrocalcite in South America.","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129423609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ta and Nb are considered critical raw materials; due to their properties and potential applications in wide sectors. This study deals with Sn-Ta-Nb minerals from the Penouta mine (Orense, Spain), the only active mine in Europe producing tantalum minerals. These are obtained from mining wastes accumulated during old mining jobs in tailing ponds. The industrial processing flowsheet is based on successive gravimetric stages followed by low intensity magnetic separation to reduce ferromagnetic contaminants. Sn-Ta-Nb concentrate, with grades between 35-45% Sn and 4-7% Ta2O5 and Nb2O5, is obtained in this stage with plant recoveries around 60-70% respectively. A chemical-mineralogical characterization by size fractions, FRX and DRX was carried out to implement a size classification stage using a circular vibrating screen in the processing plant. The finest fractions, containing higher grades of well liberated Sn, Ta, Nb minerals, were the feeding for dry high intensity magnetic separation (DHIMS) multifactorial tests, while, coarse fractions were re-grinded to maximize performance. The good results obtained in these tests demonstrate that two products with commercial quality could be obtained, a cassiterite concentrate with grades between 70-78% SnO2 and a tantalite-columbite concentrate with grades ranging between 12 and 14% Ta2O5 and Nb2O5, also increasing the overall recovery of the plant.
{"title":"Characterization, Classification, Dry High Intensity Magnetic Separation (DHIMS) and Re-rinding Techniques to Improve the Mineral Performance of Sn-Ta-Nb Mineral Concentrate","authors":"Jennire Nava Rosario, J. Aguado, T. González","doi":"10.3390/IECMS2021-09344","DOIUrl":"https://doi.org/10.3390/IECMS2021-09344","url":null,"abstract":"Ta and Nb are considered critical raw materials; due to their properties and potential applications in wide sectors. This study deals with Sn-Ta-Nb minerals from the Penouta mine (Orense, Spain), the only active mine in Europe producing tantalum minerals. These are obtained from mining wastes accumulated during old mining jobs in tailing ponds. The industrial processing flowsheet is based on successive gravimetric stages followed by low intensity magnetic separation to reduce ferromagnetic contaminants. Sn-Ta-Nb concentrate, with grades between 35-45% Sn and 4-7% Ta2O5 and Nb2O5, is obtained in this stage with plant recoveries around 60-70% respectively. A chemical-mineralogical characterization by size fractions, FRX and DRX was carried out to implement a size classification stage using a circular vibrating screen in the processing plant. The finest fractions, containing higher grades of well liberated Sn, Ta, Nb minerals, were the feeding for dry high intensity magnetic separation (DHIMS) multifactorial tests, while, coarse fractions were re-grinded to maximize performance. The good results obtained in these tests demonstrate that two products with commercial quality could be obtained, a cassiterite concentrate with grades between 70-78% SnO2 and a tantalite-columbite concentrate with grades ranging between 12 and 14% Ta2O5 and Nb2O5, also increasing the overall recovery of the plant.","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126060981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khalid Schellen, I. Graham, A. McKinnon, K. Privat, C. Dietz
The newly discovered Federation deposit, with a resource estimate of 2.6 Mt @ 7.7% Pb, 13.5% Zn, 0.8 g/t Au, and 9 g/t Ag, lies 10 km south of the Hera deposit within the Cobar Basin of the Lachlan Orogen. Located just north of the Erimeran Granite contact and between the Lower Amphitheatre Group and underlying shallow marine Mouramba Group Roset Sandstone, the host siltstones and sandstones have been brecciated, intensely silicified, and chloritized close to mineralization. Oriented in an overall east-northeast strike and with a steep south-southeast dip, the siltstones mainly comprise quartz, clinochlore, biotite, and muscovite. Federation also has highly fragmented zones with breccia and vein-fill of calcite. The main ore mineralization includes sphalerite and galena, with lesser chalcopyrite, pyrrhotite, pyrite, gold, and very rare meneghinite. Mineralization occurs within silicified veins and breccias of Zn-Pb sulfides, which generally grade to moderate veining of sulfides with Pb and Cu dominant sulfides, as well as minor veining of base metals associated with visible gold. Mineralization throughout the deposit is fairly simple, with a low diversity of minerals. Iron concentration varies throughout the deposit, decreasing towards the center. Observations of massive sphalerite with gradations of red to honeycomb yellow indicate the transition from high Fe (7–10%) to low Fe (2–5%) within the coarse sulfide assemblages over a very short distance. Within the main mineralized corridor, fibrous amphibole inclusions within galena/sphalerite assemblages are observed at 251 m, as well as epidote associated with sulfides at 573 m. Other ore-associated gangue minerals include ilmenite, siderite, scheelite, magnetite, apatite, and rutile.
{"title":"The Ore and Gangue Mineralogy of the Newly-Discovered Federation Deposit, Central NSW, Australia","authors":"Khalid Schellen, I. Graham, A. McKinnon, K. Privat, C. Dietz","doi":"10.3390/iecms2021-09348","DOIUrl":"https://doi.org/10.3390/iecms2021-09348","url":null,"abstract":"The newly discovered Federation deposit, with a resource estimate of 2.6 Mt @ 7.7% Pb, 13.5% Zn, 0.8 g/t Au, and 9 g/t Ag, lies 10 km south of the Hera deposit within the Cobar Basin of the Lachlan Orogen. Located just north of the Erimeran Granite contact and between the Lower Amphitheatre Group and underlying shallow marine Mouramba Group Roset Sandstone, the host siltstones and sandstones have been brecciated, intensely silicified, and chloritized close to mineralization. Oriented in an overall east-northeast strike and with a steep south-southeast dip, the siltstones mainly comprise quartz, clinochlore, biotite, and muscovite. Federation also has highly fragmented zones with breccia and vein-fill of calcite. The main ore mineralization includes sphalerite and galena, with lesser chalcopyrite, pyrrhotite, pyrite, gold, and very rare meneghinite. Mineralization occurs within silicified veins and breccias of Zn-Pb sulfides, which generally grade to moderate veining of sulfides with Pb and Cu dominant sulfides, as well as minor veining of base metals associated with visible gold. Mineralization throughout the deposit is fairly simple, with a low diversity of minerals. Iron concentration varies throughout the deposit, decreasing towards the center. Observations of massive sphalerite with gradations of red to honeycomb yellow indicate the transition from high Fe (7–10%) to low Fe (2–5%) within the coarse sulfide assemblages over a very short distance. Within the main mineralized corridor, fibrous amphibole inclusions within galena/sphalerite assemblages are observed at 251 m, as well as epidote associated with sulfides at 573 m. Other ore-associated gangue minerals include ilmenite, siderite, scheelite, magnetite, apatite, and rutile.","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131099751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Gjyli, A. Korpa, V. Teneqja, D. Siliqi, C. Belviso
Fly Ash is a coal combustion product partly disposed of in landfills since it finds no other application. Recycling this solid is of great benefit in terms of quality, cost effectiveness and environment. The chemical and mineralogical composition of siliceous fly ash makes it an attractive and economic raw material for the synthesis of zeolites. Zeolites are microporous, aluminosilicate minerals characterized by a three-dimensional network of tetrahedral units produced industrially on a large scale. In this work synthetic zeolite X and zeolite A with a high crystallinity and high value of surface area were synthesized by pre-fusion method followed by hydrothermal treatment at various conditions. The data indicate that zeolitic products were obtained using NaOH while no zeolitic material was crystallized using KOH and LiOH. Pre-treatment of fly ash with acid before being used in the synthesis of artificial zeolites is considered an important parameter for the purity phase of zeolites. Without sodium aluminate additions, synthetic zeolite A was not formed. The results confirm that temperature, crystallization time, SiO2/Al2O3 ratio, type of water (distilled water and seawater), are also important parameters influencing type of zeolite synthesized. Zeolite X was used as novel catalyst for alkylation of phenol using diethyl carbonate.
{"title":"Siliceous Fly Ash Utilization Conditions for Zeolite Synthesis","authors":"S. Gjyli, A. Korpa, V. Teneqja, D. Siliqi, C. Belviso","doi":"10.3390/IECMS2021-09359","DOIUrl":"https://doi.org/10.3390/IECMS2021-09359","url":null,"abstract":"Fly Ash is a coal combustion product partly disposed of in landfills since it finds no other application. Recycling this solid is of great benefit in terms of quality, cost effectiveness and environment. The chemical and mineralogical composition of siliceous fly ash makes it an attractive and economic raw material for the synthesis of zeolites. Zeolites are microporous, aluminosilicate minerals characterized by a three-dimensional network of tetrahedral units produced industrially on a large scale. In this work synthetic zeolite X and zeolite A with a high crystallinity and high value of surface area were synthesized by pre-fusion method followed by hydrothermal treatment at various conditions. The data indicate that zeolitic products were obtained using NaOH while no zeolitic material was crystallized using KOH and LiOH. Pre-treatment of fly ash with acid before being used in the synthesis of artificial zeolites is considered an important parameter for the purity phase of zeolites. Without sodium aluminate additions, synthetic zeolite A was not formed. The results confirm that temperature, crystallization time, SiO2/Al2O3 ratio, type of water (distilled water and seawater), are also important parameters influencing type of zeolite synthesized. Zeolite X was used as novel catalyst for alkylation of phenol using diethyl carbonate.","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125047966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Jiménez, A. Misol, Á. Morato, M. Vicente, V. Rives, R. Trujillano, A. Gil, S. Korili
Nowadays scientific and technological advances have allowed to Mankind to improve the life-style, but in this way, other problems have appeared. Currently, environmental problems are one of the most important. Many countries have developed a large number of environmental laws with the purpose of reducing human and industrial effects in the environment. In this work, a valorization procedure is developed for one of the most important wastes generated during aluminum recycling, namely, saline slag, finding that the final solids can be used for environmental applications. The procedure is divided into two steps: 1) recovery of aluminum from various slag fractions, and b) the use of recovered aluminum in the synthesis of two zeolites, namely, analcime (NaAlSi2O6·H2O) and pollucite (CsAlSi2O6·nH2O). Saline slag was ground, sieved (1 mm), washed and separated into two fractions of different sizes, one larger than 0.4 mm and other lower than 0.4 mm. The fraction <0.4 mm was treated under reflux conditions with NaOH or CsOH solutions of different concentrations. The extraction liquor contained aluminum and alkali metal cations; thus after adding the necessary amount of Si, hydrothermal synthesis was carried out at 200 °C for 24 hours, obtaining the zeolitic materials. The solids were characterized by powder X-ray diffraction, thermal analysis, FT–IR spectroscopy, element chemical analysis and electron microscopy. The results of the first step showed that a high percentage of Al (~ 44 wt.%) in the fraction <0.4 mm, can be recovered. The results of the second step indicated that crystalline analcime and pollucite zeolites can be hydrothermally synthesized from extractions liquors and a source of Si, being the only phases detected by PXRD. Acknowledgements. MINECO and ERDF (financing, MAT2016-78863-C2-R). Junta de Castilla y Leon (formation programs, AJ and AM). Santander Bank (AG).
{"title":"Preparation of Pollucite and Analcime Zeolites as a Method to Valorize Aluminum Saline Slags","authors":"A. Jiménez, A. Misol, Á. Morato, M. Vicente, V. Rives, R. Trujillano, A. Gil, S. Korili","doi":"10.3390/iecms2021-09335","DOIUrl":"https://doi.org/10.3390/iecms2021-09335","url":null,"abstract":"Nowadays scientific and technological advances have allowed to Mankind to improve the life-style, but in this way, other problems have appeared. Currently, environmental problems are one of the most important. Many countries have developed a large number of environmental laws with the purpose of reducing human and industrial effects in the environment. In this work, a valorization procedure is developed for one of the most important wastes generated during aluminum recycling, namely, saline slag, finding that the final solids can be used for environmental applications. The procedure is divided into two steps: 1) recovery of aluminum from various slag fractions, and b) the use of recovered aluminum in the synthesis of two zeolites, namely, analcime (NaAlSi2O6·H2O) and pollucite (CsAlSi2O6·nH2O). Saline slag was ground, sieved (1 mm), washed and separated into two fractions of different sizes, one larger than 0.4 mm and other lower than 0.4 mm. The fraction <0.4 mm was treated under reflux conditions with NaOH or CsOH solutions of different concentrations. The extraction liquor contained aluminum and alkali metal cations; thus after adding the necessary amount of Si, hydrothermal synthesis was carried out at 200 °C for 24 hours, obtaining the zeolitic materials. The solids were characterized by powder X-ray diffraction, thermal analysis, FT–IR spectroscopy, element chemical analysis and electron microscopy. The results of the first step showed that a high percentage of Al (~ 44 wt.%) in the fraction <0.4 mm, can be recovered. The results of the second step indicated that crystalline analcime and pollucite zeolites can be hydrothermally synthesized from extractions liquors and a source of Si, being the only phases detected by PXRD. \u0000Acknowledgements. MINECO and ERDF (financing, MAT2016-78863-C2-R). Junta de Castilla y Leon (formation programs, AJ and AM). Santander Bank (AG).","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126603891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Chile has developed its mining industry for decades, mainly in the north of the country, where arid climates dominate. Many of these tailings have been abandoned to the weather. The evaluation of what happens at the surface of abandoned tailings, depending on the dominant mineralogy and climate, will be critical in assessing potential impacts from wind erosion or reworking of these deposits. Two areas of study with different climates ranging from arid to semi-arid were evaluated by mineralogy, chemistry and particle size. Using statistical analysis, it was possible to establish different types of sediments, which mainly differed in secondary mineralogy, giving rise to three clusters. When observing these clusters in the field, different surfaces can be observed, in terms of their cohesion and wind erodibility potential. The mineralogical analysis of each cluster in both climates show that although the surfaces of the deposits are similar, the particle size, amount of pyrite and other phases vary from one site to another. From the characterization of these sites, it is evident that pyrite alone will not generate acidic solutions that lead to the precipitation of secondary phases. These secondary phases will be linked to the climate (meaning available humidity), particle size and quantity of pyrite present and neutralising phases. Depending on these variables, different potentially erodible surfaces will be generated, which will lead to a greater or lesser cohesion of particles and different metal contents which is, in turn, the reason for these tailings to become a public health issue.
{"title":"Wind erosion and factors controlling the surface composition in abandoned tailings","authors":"Javiera Gerding, A. Novoselov, J. Morales","doi":"10.3390/iecms2021-09355","DOIUrl":"https://doi.org/10.3390/iecms2021-09355","url":null,"abstract":": Chile has developed its mining industry for decades, mainly in the north of the country, where arid climates dominate. Many of these tailings have been abandoned to the weather. The evaluation of what happens at the surface of abandoned tailings, depending on the dominant mineralogy and climate, will be critical in assessing potential impacts from wind erosion or reworking of these deposits. Two areas of study with different climates ranging from arid to semi-arid were evaluated by mineralogy, chemistry and particle size. Using statistical analysis, it was possible to establish different types of sediments, which mainly differed in secondary mineralogy, giving rise to three clusters. When observing these clusters in the field, different surfaces can be observed, in terms of their cohesion and wind erodibility potential. The mineralogical analysis of each cluster in both climates show that although the surfaces of the deposits are similar, the particle size, amount of pyrite and other phases vary from one site to another. From the characterization of these sites, it is evident that pyrite alone will not generate acidic solutions that lead to the precipitation of secondary phases. These secondary phases will be linked to the climate (meaning available humidity), particle size and quantity of pyrite present and neutralising phases. Depending on these variables, different potentially erodible surfaces will be generated, which will lead to a greater or lesser cohesion of particles and different metal contents which is, in turn, the reason for these tailings to become a public health issue.","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121514892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Molina, A. Cambeses, J. Moreno, I. Morales, C. Lázaro, P. Montero, F. Bea
The classical Al-in-hornblende barometer has been very successful in determining the depth of intrusion of metaluminous cordilleran granitoid plutons that bear the buffering assemblage at near solidus conditions: hornblende-biotite-plagioclase-orthoclase-quartz-sphene-two Fe-Ti-oxides (or one Fe-Ti oxide + epidote)-melt-vapor (e.g., [1-3]). Ridolfi et al. [4] and Ridolfi and Renzulli [5] derived empirical amphibole-only barometric expressions that could be potentially applied to a larger number of phenocrystic assemblages from volcanic rocks. However, Erdmann et al. [6] claimed that these barometers are inaccurate and can give untenable estimates. A graphical barometer based on the partitioning of Al and Si between amphibole and plagioclase was derived by Fershtater [7] using amphibole-plagioclase compositional pairs of rocks from the Urals. More recently, Molina et al. [8] calibrated an empirical expression based on experimental data that can be applied to igneous and high-grade metamorphic rocks. In order to compare the reliability of amphibole-only and amphibole-plagioclase barometry, in this work, we test the performance of the expressions of Ridolfi and Renzulli [5] and Molina et al. [8], using an experimental data set compiled from the literature that has been recently published by Molina et al. [9]. In accordance with Erdmann et al.[6], the test reveals unsustainable pressure estimates with the amphibole-only barometric expressions from Ridolfi and Renzulli [5]. By contrast, the amphibole-plagioclase barometer from Molina et al. [8] performs well and yields a precision better than 1.7 kbar for Qz-Amp-Pl and Ol-free-Cpx-Amp-Pl assemblages with amphibole compositions having > 1 apfu (23O; normalisation to 13-CNK) Al, 0.05-0.27 apfu Ti: and < 1.07 apfu Fe3+. References 1. Hammarstrom and Zen, 1986, American Mineralogist 71, 1297–1313. 2 Schmidt, 1992, Contributions to Mineralogy and Petrology 110, 304–310. 3. Anderson and Smith, 1995, American Mineralogist 80, 549-449. 4. Ridolfi et al., 2010, Contributions to Mineralogy and Petrology 160, 45–66. 5. Ridolfi and Renzulli, 2012, Contributions to Mineralogy and Petrology 163, 877–895. 6. Erdmann et al., 2014, Contributions to Mineralogy and Petrology 167, 1016 7. Fershtater, 1990, Geokhimiya 3, 328–335. 8. Molina et al., 2015, Lithos 232 286–305. 9. Molina et al., 2020; American Mineralogist, in press, https://doi.org/10.2138/am-2020-7400
经典的al -in-角闪石气压计非常成功地确定了在近固相条件下具有缓冲组合的铝质科迪勒岩花岗岩类岩体的侵入深度:角闪石-黑云母-斜长石-正长石-石英-榍石-两种铁-钛氧化物(或一种铁-钛氧化物+绿帘石)-熔融蒸汽(例如[1-3])。Ridolfi et al.[4]和Ridolfi and Renzulli[5]推导出仅角闪岩的经验气压表达式，这些表达式可能应用于更多的火山岩斑晶组合。然而，Erdmann等人声称，这些晴雨表是不准确的，可以给出站不住脚的估计。Fershtater b[7]利用乌拉尔地区的角闪石-斜长石组成对，导出了一个基于角闪石-斜长石之间Al和Si分异的图解晴雨表。最近，Molina等人根据实验数据校准了一个经验表达式，该表达式可应用于火成岩和高级变质岩。为了比较双角石-斜长石和双角石-斜长石气压测定法的可靠性，在这项工作中，我们使用Molina et al.[9]最近发表的文献中编译的实验数据集，测试了Ridolfi和Renzulli[5]和Molina et al.[8]的表达式的性能。根据Erdmann等人[bb1]的研究，该测试揭示了Ridolfi和Renzulli bb1仅含角闪石的气压表达式的不可持续压力估计。相比之下，Molina et al.[8]的角闪石-斜长石气压计表现良好，对于含有> 1 apfu (23O)的角闪石成分的Qz-Amp-Pl和Ol-free-Cpx-Amp-Pl组合，精度优于1.7 kbar;正态化到13-CNK) Al, 0.05-0.27 apfu Ti:和< 1.07 apfu Fe3+。引用1。陈志刚，1986，《矿物学》第1期，1297-1313页。[2]施密特，1992，矿物学与岩石学的贡献(11)，304-310。3.安德森和史密斯，1995，美国矿物学80,549-449。4. Ridolfi et al.， 2010，矿物学与岩石学贡献，160,45-66。5. Ridolfi和Renzulli, 2012，矿物学和岩石学贡献163,877-895。6. Erdmann et al.， 2014，矿物学和岩石学贡献167,1016。科学通报，1990,3(3):328-335。8. Molina et al.， 2015, vol . 32(2): 286-305。9. Molina et al.， 2020;美国矿物学家，出版中，https://doi.org/10.2138/am-2020-7400
{"title":"A Cautionary Note on Amphibole Geobarometry","authors":"J. Molina, A. Cambeses, J. Moreno, I. Morales, C. Lázaro, P. Montero, F. Bea","doi":"10.3390/IECMS2021-09346","DOIUrl":"https://doi.org/10.3390/IECMS2021-09346","url":null,"abstract":"The classical Al-in-hornblende barometer has been very successful in determining the depth of intrusion of metaluminous cordilleran granitoid plutons that bear the buffering assemblage at near solidus conditions: hornblende-biotite-plagioclase-orthoclase-quartz-sphene-two Fe-Ti-oxides (or one Fe-Ti oxide + epidote)-melt-vapor (e.g., [1-3]). \u0000Ridolfi et al. [4] and Ridolfi and Renzulli [5] derived empirical amphibole-only barometric expressions that could be potentially applied to a larger number of phenocrystic assemblages from volcanic rocks. However, Erdmann et al. [6] claimed that these barometers are inaccurate and can give untenable estimates. \u0000A graphical barometer based on the partitioning of Al and Si between amphibole and plagioclase was derived by Fershtater [7] using amphibole-plagioclase compositional pairs of rocks from the Urals. More recently, Molina et al. [8] calibrated an empirical expression based on experimental data that can be applied to igneous and high-grade metamorphic rocks. \u0000In order to compare the reliability of amphibole-only and amphibole-plagioclase barometry, in this work, we test the performance of the expressions of Ridolfi and Renzulli [5] and Molina et al. [8], using an experimental data set compiled from the literature that has been recently published by Molina et al. [9]. \u0000In accordance with Erdmann et al.[6], the test reveals unsustainable pressure estimates with the amphibole-only barometric expressions from Ridolfi and Renzulli [5]. By contrast, the amphibole-plagioclase barometer from Molina et al. [8] performs well and yields a precision better than 1.7 kbar for Qz-Amp-Pl and Ol-free-Cpx-Amp-Pl assemblages with amphibole compositions having > 1 apfu (23O; normalisation to 13-CNK) Al, 0.05-0.27 apfu Ti: and < 1.07 apfu Fe3+. \u0000References \u00001. Hammarstrom and Zen, 1986, American Mineralogist 71, 1297–1313. \u00002 Schmidt, 1992, Contributions to Mineralogy and Petrology 110, 304–310. \u00003. Anderson and Smith, 1995, American Mineralogist 80, 549-449. \u00004. Ridolfi et al., 2010, Contributions to Mineralogy and Petrology 160, 45–66. \u00005. Ridolfi and Renzulli, 2012, Contributions to Mineralogy and Petrology 163, 877–895. \u00006. Erdmann et al., 2014, Contributions to Mineralogy and Petrology 167, 1016 \u00007. Fershtater, 1990, Geokhimiya 3, 328–335. \u00008. Molina et al., 2015, Lithos 232 286–305. \u00009. Molina et al., 2020; American Mineralogist, in press, https://doi.org/10.2138/am-2020-7400","PeriodicalId":118040,"journal":{"name":"Proceedings of The 2nd International Electronic Conference on Mineral Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116869523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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