D. Nishio–Hamane, Koichi Momma, M. Ohnishi, S. Inaba
Oxyyttrobeta fi te – (Y) is the fi rst member in the beta fi te group of the pyrochlore supergroup found in albite – rich pegmatite from Souri Valley, Komono, Mie Prefecture, Japan. This new mineral occurs as small anhedral grains with sizes of 20 to 200 µm in cylinder – shaped aggregates with a substrate of thalénite – (Y) and synchysite – (Y). Small amounts of aeschynite – (Y), thorianite, and thorite are also associated in the same occurrence with oxyyttrobeta fi te – (Y), and gadolinite – (Y) is also included at the boundary between the aggregate and albite. The physical properties are: brown in color, brittle, transparent, non – fl uorescent, vitreous luster, white streak with a Mohs hardness of 5, and a calculated density of 5.54 g·cm − 3 . Oxyyttrobeta fi te – (Y) is an optically isometric material with brown color under the microscope with a refractive index of n = 2.3 calculated using the Gladstone – Dale relationship. The empirical formula of oxyyttrobeta fi te – (Y) calculated on the basis of B = 2 with A 2 B 2 X 6 Y composition is (Y 1.58 Dy
{"title":"Oxyyttrobetafite–(Y), Y2Ti2O6O, a new mineral of the pyrochlore supergroup in a pegmatite from Souri Valley, Komono, Mie Prefecture Japan","authors":"D. Nishio–Hamane, Koichi Momma, M. Ohnishi, S. Inaba","doi":"10.2465/jmps.220728","DOIUrl":"https://doi.org/10.2465/jmps.220728","url":null,"abstract":"Oxyyttrobeta fi te – (Y) is the fi rst member in the beta fi te group of the pyrochlore supergroup found in albite – rich pegmatite from Souri Valley, Komono, Mie Prefecture, Japan. This new mineral occurs as small anhedral grains with sizes of 20 to 200 µm in cylinder – shaped aggregates with a substrate of thalénite – (Y) and synchysite – (Y). Small amounts of aeschynite – (Y), thorianite, and thorite are also associated in the same occurrence with oxyyttrobeta fi te – (Y), and gadolinite – (Y) is also included at the boundary between the aggregate and albite. The physical properties are: brown in color, brittle, transparent, non – fl uorescent, vitreous luster, white streak with a Mohs hardness of 5, and a calculated density of 5.54 g·cm − 3 . Oxyyttrobeta fi te – (Y) is an optically isometric material with brown color under the microscope with a refractive index of n = 2.3 calculated using the Gladstone – Dale relationship. The empirical formula of oxyyttrobeta fi te – (Y) calculated on the basis of B = 2 with A 2 B 2 X 6 Y composition is (Y 1.58 Dy","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"10 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832437","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}
This study presents the use of petrographic plagioclase alteration indicators as a new method for quantitatively evaluating the extent of plagioclase alteration within granites, using the Toki granite, central Japan, as an example. The new petrological indicator enables us to discuss the similarities/di ff erences in the extent of alteration within a rock body and between rock bodies. Alteration indicators and areal fractions of microvoids in the plagioclase grains were obtained through the analysis of backscattered electron images. The volume of the micropores in the altered plagioclase was estimated using the areal fraction of microvoids in the grains. The plagioclase alteration indicators were obtained as the ratio between the alteration product domain and the original plagioclase domain. We found positive correlations between the plagioclase alteration and biotite chloritization indicators presented in Yuguchi et al. (2021), indicating that each alteration indicator can be used independently as a representative value for the sample. The positive correlations between the areal fraction of microvoids in the altered plagioclase and the alteration indicator in the samples and petrographic observations indicated the following: 1) the altered plagioclase contains the incipient micropores and the alteration micropores, 2) the incipient micropores, which were caused by the dissolution of plagioclase during the incipient stage of plagioclase alteration, acted as a pathway of hydrothermal fl uid within the plagioclase, resulting in alteration progress, and 3) the hydrothermal alteration resulted in the production of new alteration micropores. In the Toki granite, the progress of plagioclase alteration is essentially dominated by the progress of biotite chloritization. The progress of biotite chloritization essentially in fl uenced the progress of plagioclase
本文以日本中部Toki花岗岩为例，提出了利用岩相斜长石蚀变指标定量评价花岗岩内斜长石蚀变程度的新方法。新的岩石学指标使我们能够讨论一个岩体内和岩体之间蚀变程度的异同。通过背向散射电子图像分析，获得了斜长石颗粒的蚀变指标和微孔的面积分数。蚀变斜长石中微孔的体积是用颗粒中微孔的面积分数来估计的。斜长石蚀变指标为蚀变产物域与原斜长石域之比。我们发现Yuguchi et al.(2021)提出的斜长石蚀变与黑云母绿泥化指标之间存在正相关关系，表明每种蚀变指标都可以独立作为样品的代表性值。蚀变斜长石中微孔的面积分数与样品中的蚀变指标和岩石学观察呈正相关，表明:蚀变斜长石包含有初始微孔和蚀变微孔;2)初始微孔是斜长石蚀变初期溶蚀作用形成的，是热液流体在斜长石内部的通道，导致蚀变进程;3)热液蚀变导致新的蚀变微孔的产生。在东木花岗岩中，斜长石蚀变的过程主要以黑云母绿岩化的过程为主。黑云母绿泥化作用的进展基本上影响了斜长石的进展
{"title":"Association of hydrothermal plagioclase alteration with micropores in a granite: Petrographic indicators to evaluate the extent of hydrothermal alteration","authors":"T. Yuguchi, Y. Izumino, E. Sasao","doi":"10.2465/jmps.220415","DOIUrl":"https://doi.org/10.2465/jmps.220415","url":null,"abstract":"This study presents the use of petrographic plagioclase alteration indicators as a new method for quantitatively evaluating the extent of plagioclase alteration within granites, using the Toki granite, central Japan, as an example. The new petrological indicator enables us to discuss the similarities/di ff erences in the extent of alteration within a rock body and between rock bodies. Alteration indicators and areal fractions of microvoids in the plagioclase grains were obtained through the analysis of backscattered electron images. The volume of the micropores in the altered plagioclase was estimated using the areal fraction of microvoids in the grains. The plagioclase alteration indicators were obtained as the ratio between the alteration product domain and the original plagioclase domain. We found positive correlations between the plagioclase alteration and biotite chloritization indicators presented in Yuguchi et al. (2021), indicating that each alteration indicator can be used independently as a representative value for the sample. The positive correlations between the areal fraction of microvoids in the altered plagioclase and the alteration indicator in the samples and petrographic observations indicated the following: 1) the altered plagioclase contains the incipient micropores and the alteration micropores, 2) the incipient micropores, which were caused by the dissolution of plagioclase during the incipient stage of plagioclase alteration, acted as a pathway of hydrothermal fl uid within the plagioclase, resulting in alteration progress, and 3) the hydrothermal alteration resulted in the production of new alteration micropores. In the Toki granite, the progress of plagioclase alteration is essentially dominated by the progress of biotite chloritization. The progress of biotite chloritization essentially in fl uenced the progress of plagioclase","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Age, provenance and geological significance of (meta)–sedimentary rocks in the Yitong–Gongzhuling area, NE China: Constraints from zircon U–Pb geochronology","authors":"Shengnan Sun, Zuozhen Han, Z. Song","doi":"10.2465/jmps.211224","DOIUrl":"https://doi.org/10.2465/jmps.211224","url":null,"abstract":"","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832189","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}
Herein, an in situ high – temperature synchrotron X – ray di ff raction study of gypsum is performed in the temperature range of 30 – 200 °C to investigate the continuous structural change from gypsum to soluble anhydrite through hemihydrate. Thermogravimetric and di ff erential thermal analysis curves reveal that dehydration occurs in two stages. The di ff raction peaks of β – hemihydrate with the trigonal space group P 3 1 21 gradually become sharper above 90 °C, whereas those of gypsum become less intense and cannot be distinctly observed at 160 °C. The CaO 8 dodecahedra and SO 4 tetrahedra in gypsum expand negligibly with temperature. The site occupancy parameter of the water oxygen (Ow) atom in gypsum remains at approximately 1.0, within the experimental error. When water molecules are lost from gypsum, it immediately transforms into β – hemihydrate, without maintaining its structure. The volumetric thermal expansion coe ffi cient of gypsum is 1.31 × 10 − 4 K − 1 . The site occupancy of Ow in β – hemihydrate continuously decreases from 0.8 and reaches approximately 0.5 at temperatures of 130 – 140 °C, where soluble anhydrite with a hexagonal space group P 6 2 22 begins to form. Therefore, β – hemihydrate dehydration can be translated by the chemical formula CaSO 4 · x H 2 O (0.5 ≤ x ≤ 0.8). The volumetric thermal expansion coe ffi cient of β – hemihydrate, determined at temperatures between 90 and 140 °C is 1.54 × 10 − 4 K − 1 . β – Hemihydrate coexists with soluble anhydrite above 140 °C; however, the amount of β – hemihydrate decreases with temperature. In β – hemihydrate, water molecules are continuously released from the CaO 9 tetradecahedra, thereby resulting in its contraction. Consequently, the structural change to a smaller CaO 8 dodecahedron triggers its transformation into soluble anhydrite without the collapse of its one – dimensional linear chains. With further heating, β – hemihydrate completely transforms into soluble anhydrite at 170 °C. The volumetric thermal expansion coe ffi cient of soluble anhydrite determined in the temperature range of 170 – 200 °C is 1.69 × 10 − 5 K − 1 , which is an order of magnitude smaller than the values of gypsum and β – hemihydrate.
{"title":"Structural evolution of gypsum (CaSO4·2H2O) during thermal dehydration","authors":"A. Kyono, R. Ikeda, S. Takagi, Wataru Nishiyasu","doi":"10.2465/jmps.220811","DOIUrl":"https://doi.org/10.2465/jmps.220811","url":null,"abstract":"Herein, an in situ high – temperature synchrotron X – ray di ff raction study of gypsum is performed in the temperature range of 30 – 200 °C to investigate the continuous structural change from gypsum to soluble anhydrite through hemihydrate. Thermogravimetric and di ff erential thermal analysis curves reveal that dehydration occurs in two stages. The di ff raction peaks of β – hemihydrate with the trigonal space group P 3 1 21 gradually become sharper above 90 °C, whereas those of gypsum become less intense and cannot be distinctly observed at 160 °C. The CaO 8 dodecahedra and SO 4 tetrahedra in gypsum expand negligibly with temperature. The site occupancy parameter of the water oxygen (Ow) atom in gypsum remains at approximately 1.0, within the experimental error. When water molecules are lost from gypsum, it immediately transforms into β – hemihydrate, without maintaining its structure. The volumetric thermal expansion coe ffi cient of gypsum is 1.31 × 10 − 4 K − 1 . The site occupancy of Ow in β – hemihydrate continuously decreases from 0.8 and reaches approximately 0.5 at temperatures of 130 – 140 °C, where soluble anhydrite with a hexagonal space group P 6 2 22 begins to form. Therefore, β – hemihydrate dehydration can be translated by the chemical formula CaSO 4 · x H 2 O (0.5 ≤ x ≤ 0.8). The volumetric thermal expansion coe ffi cient of β – hemihydrate, determined at temperatures between 90 and 140 °C is 1.54 × 10 − 4 K − 1 . β – Hemihydrate coexists with soluble anhydrite above 140 °C; however, the amount of β – hemihydrate decreases with temperature. In β – hemihydrate, water molecules are continuously released from the CaO 9 tetradecahedra, thereby resulting in its contraction. Consequently, the structural change to a smaller CaO 8 dodecahedron triggers its transformation into soluble anhydrite without the collapse of its one – dimensional linear chains. With further heating, β – hemihydrate completely transforms into soluble anhydrite at 170 °C. The volumetric thermal expansion coe ffi cient of soluble anhydrite determined in the temperature range of 170 – 200 °C is 1.69 × 10 − 5 K − 1 , which is an order of magnitude smaller than the values of gypsum and β – hemihydrate.","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832449","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}
T. Hokada, T. Adachi, Y. Osanai, N. Nakano, S. Baba, T. Toyoshima
We have found corundum in direct contact with quartz and biotite and as inclusions in garnet in the pelitic gneisses of northern Austkampane in the Northeastern (NE) Terrane of the Sør Rondane Mountains (SRM), East Antarctica. Our samples, which include corundum – bearing gneisses, show petrographic features such as staurolite inclusions in garnet, compositional zoning of orthoamphibole with Al decreasing toward the rims, and late – stage cordierite formation, and these features are characteristic of a clockwise P – T trajectory. The obser-vations are consistent with the proposed regional clockwise P – T evolution of the NE Terrane in the SRM. The corundum and other inclusions observed in the garnet porphyroblasts are interpreted to have formed owing to either staurolite breakdown or metastable crystallization relative to kyanite prior to the peak metamorphism. The close association of biotite and quartz surrounding corundum inclusions suggests fl uid – or melt – related processes. These petrographic features imply that the corundum and quartz (rarely observed in high – grade metamorphic rocks) formed as a result of metastable crystallization during the prograde stage of the clockwise P – T evolution of a
{"title":"Formation of corundum in direct contact with quartz and biotite in clockwise P–T trajectory from the Sør Rondane Mountains, East Antarctica","authors":"T. Hokada, T. Adachi, Y. Osanai, N. Nakano, S. Baba, T. Toyoshima","doi":"10.2465/jmps.220317","DOIUrl":"https://doi.org/10.2465/jmps.220317","url":null,"abstract":"We have found corundum in direct contact with quartz and biotite and as inclusions in garnet in the pelitic gneisses of northern Austkampane in the Northeastern (NE) Terrane of the Sør Rondane Mountains (SRM), East Antarctica. Our samples, which include corundum – bearing gneisses, show petrographic features such as staurolite inclusions in garnet, compositional zoning of orthoamphibole with Al decreasing toward the rims, and late – stage cordierite formation, and these features are characteristic of a clockwise P – T trajectory. The obser-vations are consistent with the proposed regional clockwise P – T evolution of the NE Terrane in the SRM. The corundum and other inclusions observed in the garnet porphyroblasts are interpreted to have formed owing to either staurolite breakdown or metastable crystallization relative to kyanite prior to the peak metamorphism. The close association of biotite and quartz surrounding corundum inclusions suggests fl uid – or melt – related processes. These petrographic features imply that the corundum and quartz (rarely observed in high – grade metamorphic rocks) formed as a result of metastable crystallization during the prograde stage of the clockwise P – T evolution of a","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"264 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832633","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}
Attempts to synthesize transparent polycrystalline jadeite have been made by direct conversion from bulk glass at pressures 10 – 20 GPa and temperatures 900 – 1300 °C using Kawai – type multianvil apparatus. The grain size of jadeite tends to decrease with increasing pressure, but we failed to synthesize polycrystalline jadeite with grain sizes in nano – regime (<100 nm) and obtained the sample with the smallest average grain size of ~ 240 nm at 20 GPa and 1300 °C for 20 min. Polycrystalline jadeite of the minimum grain size exhibits high optical transparency with a transmittance of ~ 70% for a typical wavelength in the visible region. The highest Vickers hardness (H v ) of 14.2 GPa was observed for the polycrystalline jadeite sample with the minimum grain size of ~240 nm, which is about 7% higher than the hardness (H v = 13.3 GPa) of the sample with the largest grain size of ~ 390 nm. Further increases in optical transparency and hardness of polycrystalline jadeite would be realized if we get nano – polycrystalline samples by optimizing pressure, temperature, heating duration, etc. of the ultrahigh – pressure synthesis experiment.
{"title":"Synthesis of transparent polycrystalline jadeite under high pressure and temperature","authors":"Keisuke Mitsu, T. Irifune, H. Ohfuji, A. Yamada","doi":"10.2465/jmps.210319","DOIUrl":"https://doi.org/10.2465/jmps.210319","url":null,"abstract":"Attempts to synthesize transparent polycrystalline jadeite have been made by direct conversion from bulk glass at pressures 10 – 20 GPa and temperatures 900 – 1300 °C using Kawai – type multianvil apparatus. The grain size of jadeite tends to decrease with increasing pressure, but we failed to synthesize polycrystalline jadeite with grain sizes in nano – regime (<100 nm) and obtained the sample with the smallest average grain size of ~ 240 nm at 20 GPa and 1300 °C for 20 min. Polycrystalline jadeite of the minimum grain size exhibits high optical transparency with a transmittance of ~ 70% for a typical wavelength in the visible region. The highest Vickers hardness (H v ) of 14.2 GPa was observed for the polycrystalline jadeite sample with the minimum grain size of ~240 nm, which is about 7% higher than the hardness (H v = 13.3 GPa) of the sample with the largest grain size of ~ 390 nm. Further increases in optical transparency and hardness of polycrystalline jadeite would be realized if we get nano – polycrystalline samples by optimizing pressure, temperature, heating duration, etc. of the ultrahigh – pressure synthesis experiment.","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42686705","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}
H. Hongu, A. Yoshiasa, Ginga Kitahara, Yumiko Miyano, K. Han, Koichi Momma, R. Miyawaki, M. Tokuda, K. Sugiyama
{"title":"Crystal structure refinement and crystal chemistry of parasymplesite and vivianite","authors":"H. Hongu, A. Yoshiasa, Ginga Kitahara, Yumiko Miyano, K. Han, Koichi Momma, R. Miyawaki, M. Tokuda, K. Sugiyama","doi":"10.2465/jmps.200904","DOIUrl":"https://doi.org/10.2465/jmps.200904","url":null,"abstract":"","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41333187","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}
M. Enami, Ayano Nishii, T. Mouri, M. Tsuboi, Y. Kouketsu
Olivine is a major mineral in ultrama fi c and ma fi c rocks. Due to the higher Mg/Fe partition coe ffi cient of olivine than the coexisting phases, the occurrences of Mg – poorer olivine grains, especially with Mg#[= Mg/(Mg + Fe 2+ )] = 0.2 – 0.6, are rarely reported, and thus, their spectroscopic data are limited. Fe – rich olivine phenocrysts showing compositional zoning with Mg# = ~ 0.5 (core) and ~ 0.3 (rim) and microphenocrysts with Mg# = ~ 0.4 (core) and ~ 0.2 (rim) occur in basaltic trachyandesite of Miocene Shitara volcanic rocks in central Japan. These olivine grains were investigated by Raman spectroscopy. Combining our data with the published values, we have revised the equation for Mg# – Raman spectrum relationship proposed by Mouri and Enami (2008) as follows: Mg# = 0.005446 ω 2 − 0.20259 ω + 1.8442 (correlation coe ffi cient r 2 = 0.984), where ω is the di ff erence between the doublet peak positions ( κ 2 − κ 1 ).
{"title":"Fe–rich olivine from an andesite dike in Miocene Shitara volcanic rocks, central Japan: a revised relationship between Mg/Fe ratio and Raman spectrum in olivine","authors":"M. Enami, Ayano Nishii, T. Mouri, M. Tsuboi, Y. Kouketsu","doi":"10.2465/JMPS.201204","DOIUrl":"https://doi.org/10.2465/JMPS.201204","url":null,"abstract":"Olivine is a major mineral in ultrama fi c and ma fi c rocks. Due to the higher Mg/Fe partition coe ffi cient of olivine than the coexisting phases, the occurrences of Mg – poorer olivine grains, especially with Mg#[= Mg/(Mg + Fe 2+ )] = 0.2 – 0.6, are rarely reported, and thus, their spectroscopic data are limited. Fe – rich olivine phenocrysts showing compositional zoning with Mg# = ~ 0.5 (core) and ~ 0.3 (rim) and microphenocrysts with Mg# = ~ 0.4 (core) and ~ 0.2 (rim) occur in basaltic trachyandesite of Miocene Shitara volcanic rocks in central Japan. These olivine grains were investigated by Raman spectroscopy. Combining our data with the published values, we have revised the equation for Mg# – Raman spectrum relationship proposed by Mouri and Enami (2008) as follows: Mg# = 0.005446 ω 2 − 0.20259 ω + 1.8442 (correlation coe ffi cient r 2 = 0.984), where ω is the di ff erence between the doublet peak positions ( κ 2 − κ 1 ).","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"6 5","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41246302","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}
Yuma Morimitsu, Y. Shirose, S. Enju, K. Tsuruta, N. Shimobayashi
Zaïrite was found from the quartz vein penetrating into the metamorphosed mudstone of the Wazuka Unit in Ishidera area, – Prefecture, which is the fi rst occurrence in Japan. Zaïrite occurs as bright – yellow granular crystals (20 – 30 µm) in a cavity formed by the leaching of fl uorapatite with native bismuth inclusion. The chemical composition of zaïrite from Ishidera was closer to the ideal chemical composition, comparing with the zaïrite from type locality including Al. The empirical formula from electron probe micro-analyzer (EPMA) analysis on the basis of O = 8, OH − = 6 was (Bi 0.70 Ca 0.23 ) Σ 0.93 Fe 3+2.91 (P 2.04 S 0.09 O 8 )(OH) 6 . The unit cell parameters obtained from the X – ray di ff raction (XRD) pattern were a = 7.311(3) Å and c = 16.407(7) Å, larger than the type locality due to di ff erence in chemical composition.
Zaïrite是在日本石得县石寺地区洼冢组的变质泥岩中穿透的石英脉中发现的，为日本首次发现。Zaïrite以亮黄色颗粒状晶体(20 - 30µm)的形式出现在含天然铋包裹体的氟磷灰石浸出形成的空腔中。石原地区的zaïrite化学成分比Al地区的zaïrite更接近理想化学成分。在O = 8, OH−= 6的基础上，电子探针微分析仪(EPMA)分析得出的经验公式为(Bi 0.70 Ca 0.23) Σ 0.93 Fe 3+2.91 (P 2.04 S 0.09 O 8)(OH) 6。X射线衍射(XRD)图得到的单晶胞参数为a = 7.311(3) Å， c = 16.407(7) Å，由于化学成分的差异大于类型局域。
{"title":"Zaïrite in quartz veins from Ishidera area, Wazuka, Kyoto Prefecture, Japan","authors":"Yuma Morimitsu, Y. Shirose, S. Enju, K. Tsuruta, N. Shimobayashi","doi":"10.2465/JMPS.201130D","DOIUrl":"https://doi.org/10.2465/JMPS.201130D","url":null,"abstract":"Zaïrite was found from the quartz vein penetrating into the metamorphosed mudstone of the Wazuka Unit in Ishidera area, – Prefecture, which is the fi rst occurrence in Japan. Zaïrite occurs as bright – yellow granular crystals (20 – 30 µm) in a cavity formed by the leaching of fl uorapatite with native bismuth inclusion. The chemical composition of zaïrite from Ishidera was closer to the ideal chemical composition, comparing with the zaïrite from type locality including Al. The empirical formula from electron probe micro-analyzer (EPMA) analysis on the basis of O = 8, OH − = 6 was (Bi 0.70 Ca 0.23 ) Σ 0.93 Fe 3+2.91 (P 2.04 S 0.09 O 8 )(OH) 6 . The unit cell parameters obtained from the X – ray di ff raction (XRD) pattern were a = 7.311(3) Å and c = 16.407(7) Å, larger than the type locality due to di ff erence in chemical composition.","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45142626","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 major and trace element characteristics of the clinopyroxene from two generations of dykes, dolerite and olivine dolerite dykes of Western Dharwar Craton were investigated by using electron microprobe and LA – ICPMS. The clinopyroxene in dolerite dykes show a compositional zoning with Mg# decreasing from the core to the rim (85 to 51) and Cr 2 O 3 contents decrease towards the rim. The trace and rare earth element (REE) pattern of the core shows lower concentrations of REEs compared to the rim. The clinopyroxene in the olivine dolerites are devoid of zoning and compositionally more primitive than the dolerites as visible in the trace element and REE concentrations. The dolerite and olivine dolerite are formed from di ff erent source magmas and the fractional crystallization of clinopyroxene is dominant in dolerites. The present estimated melt composition in equilibrium with clinopyroxene is consistent with the bulk rock composition for dolerite and olivine dolerite.
{"title":"Trace and rare earth element geochemistry of clinopyroxene in mafic dykes from Western Dharwar craton, southern India","authors":"S. Silpa, M. Satish‐Kumar, E. Takazawa, K. Sajeev","doi":"10.2465/JMPS.201130C","DOIUrl":"https://doi.org/10.2465/JMPS.201130C","url":null,"abstract":"The major and trace element characteristics of the clinopyroxene from two generations of dykes, dolerite and olivine dolerite dykes of Western Dharwar Craton were investigated by using electron microprobe and LA – ICPMS. The clinopyroxene in dolerite dykes show a compositional zoning with Mg# decreasing from the core to the rim (85 to 51) and Cr 2 O 3 contents decrease towards the rim. The trace and rare earth element (REE) pattern of the core shows lower concentrations of REEs compared to the rim. The clinopyroxene in the olivine dolerites are devoid of zoning and compositionally more primitive than the dolerites as visible in the trace element and REE concentrations. The dolerite and olivine dolerite are formed from di ff erent source magmas and the fractional crystallization of clinopyroxene is dominant in dolerites. The present estimated melt composition in equilibrium with clinopyroxene is consistent with the bulk rock composition for dolerite and olivine dolerite.","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":" ","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47650826","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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