This paper reports the fi rst outcrop occurrence of an ultrahigh – temperature (UHT) metamorphic rock from the Sør Rondane Mountains (SRM), East Antarctica. A pelitic gneiss from Balchenfjella, eastern SRM, contains mesoperthite that gave UHT condition (>900 °C) by ternary feldspar thermometry. The UHT mesoperthite is present both in the matrix and as an inclusion in garnet. The garnet also has nanogranitoid inclusions next to the mesoperthite, which are interpreted to be an UHT melt. The re – integrated nanogranitoid composition is plotted in the primary phase region of quartz and classi fi ed as granite. Even crystallized nanogranitoids can provide appropriate original melt composition in the An – Ab – Or and Qz – Ab – Or spaces, whereas Mg concentration is enriched due to local retrograde Fe – Mg exchange reaction between the nanogranitoid inclusions and the host garnet. Although metamorphic rocks in the SRM are highly retrogressed, this study revealed that the micro-structural evidence of UHT condition is partially preserved. Further investigation of timing and areal extent of UHT metamorphism helps us to understand the tectonic model of the SRM.
本文报道了南极东部朗丹山(SRM)超高温变质岩的首次露头。SRM东部Balchenfjella的泥质片麻岩含中长辉石，经三元长石测温，其UHT条件(bb0 ~ 900℃)。超高温中辉长岩既存在于基体中，也以石榴石包裹体的形式存在。石榴石在中长岩旁边也有纳米花岗岩类包裹体，这被解释为UHT熔体。在石英原生相区绘制了重积分的纳米花岗岩组成，归类为花岗岩。在An - Ab - Or和Qz - Ab - Or空间中，即使纳米花岗岩结晶也能提供合适的初始熔体成分，而镁的富集则是由于纳米花岗岩包裹体与主石榴石之间局部的铁-镁逆行交换反应。虽然SRM中的变质岩是高度退变的，但研究表明，UHT条件下的微结构证据被部分保存。对超高温变质作用的时间和面积范围的进一步研究有助于我们了解SRM的构造模式。
{"title":"Ultrahigh–temperature metamorphism and melt inclusions from the Sør Rondane Mountains, East Antarctica","authors":"Fumiko Higashino, Tetsuo Kawakami","doi":"10.2465/jmps.220325","DOIUrl":"https://doi.org/10.2465/jmps.220325","url":null,"abstract":"This paper reports the fi rst outcrop occurrence of an ultrahigh – temperature (UHT) metamorphic rock from the Sør Rondane Mountains (SRM), East Antarctica. A pelitic gneiss from Balchenfjella, eastern SRM, contains mesoperthite that gave UHT condition (>900 °C) by ternary feldspar thermometry. The UHT mesoperthite is present both in the matrix and as an inclusion in garnet. The garnet also has nanogranitoid inclusions next to the mesoperthite, which are interpreted to be an UHT melt. The re – integrated nanogranitoid composition is plotted in the primary phase region of quartz and classi fi ed as granite. Even crystallized nanogranitoids can provide appropriate original melt composition in the An – Ab – Or and Qz – Ab – Or spaces, whereas Mg concentration is enriched due to local retrograde Fe – Mg exchange reaction between the nanogranitoid inclusions and the host garnet. Although metamorphic rocks in the SRM are highly retrogressed, this study revealed that the micro-structural evidence of UHT condition is partially preserved. Further investigation of timing and areal extent of UHT metamorphism helps us to understand the tectonic model of the SRM.","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":"68832699","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}
Yuya Itami, D. Nakamura, Atsushi Yasumoto, T. Hirajima, M. Svojtka
The origins of eclogite associated with garnet peridotite in continent – continent collision belts are still debated. We performed petrological studies of eclogites collected from a garnet peridotite block from Nové Dvory in the Gföhl Unit of the Moldanubian Zone in the Variscan orogenic belt, Czech Republic. The eclogite was divided into three types: one kyanite (Ky) – bearing and two Ky – free types. Garnet and omphacite in the Ky – bearing eclogite have lower Fe contents than those in the Ky – free eclogite. Furthermore, the Ky – free eclogite was divided into two types on the basis of Ca content in garnet: Ca – rich ( X grs > 0.32) and Ca – poor ( X grs < 0.32) types, except for Ca – poor rim compositions. Application of conventional geothermobarometers to the Ky – bearing type and the Ky – free type with Ca – rich garnet yielded similar pressure – temperature ( P – T ) conditions (3.2 – 4.8 GPa and 920 – 1160 °C) to those of previous studies, whereas the Ky – free type with Ca – poor garnet yielded slightly lower P – T conditions (3.1 – 3.4 GPa and 950 – 990 °C) than the other two types. The observed chemical variation of garnet is probably due to the di ff erence in origins, whereby, according to our new results and previous fi ndings, the Ky – bearing eclogite was derived from plagioclase – bearing crustal gabbro, whereas the Ky – free eclogite with Ca – rich garnet was derived from a crystal cumulate possibly in the mantle wedge. In the Ky – free eclogite samples with Ca – poor garnet, chemical compositions of garnet and omphacite are di ff erent from those in the other Ky – free samples, and those samples with Ca – poor garnet would have a di ff erent origin from the others. One of the Ky – free type with Ca – poor garnet retains garnet grains with chemical zonings probably created during the prograde history, although the eclogite underwent the extremely high temperature (~ 1000 °C) metamorphism. Calculated di ff usion distances in garnet reach 0.5 mm during 2 million years, even if we adopted a low value of di ff usion coe ffi cient data. Thus, the residence time of the eclogite at the peak meatamorphic conditions would have been shorter than at least 2 million years. The subsequent decompression and cooling after the peak metamorphism were also probably very fast to avoid the chemical homogenization of garnet.
{"title":"Multiple origins of UHP eclogites in a garnet peridotite block (Nové Dvory, Czech Republic) and short duration of heating","authors":"Yuya Itami, D. Nakamura, Atsushi Yasumoto, T. Hirajima, M. Svojtka","doi":"10.2465/jmps.220221","DOIUrl":"https://doi.org/10.2465/jmps.220221","url":null,"abstract":"The origins of eclogite associated with garnet peridotite in continent – continent collision belts are still debated. We performed petrological studies of eclogites collected from a garnet peridotite block from Nové Dvory in the Gföhl Unit of the Moldanubian Zone in the Variscan orogenic belt, Czech Republic. The eclogite was divided into three types: one kyanite (Ky) – bearing and two Ky – free types. Garnet and omphacite in the Ky – bearing eclogite have lower Fe contents than those in the Ky – free eclogite. Furthermore, the Ky – free eclogite was divided into two types on the basis of Ca content in garnet: Ca – rich ( X grs > 0.32) and Ca – poor ( X grs < 0.32) types, except for Ca – poor rim compositions. Application of conventional geothermobarometers to the Ky – bearing type and the Ky – free type with Ca – rich garnet yielded similar pressure – temperature ( P – T ) conditions (3.2 – 4.8 GPa and 920 – 1160 °C) to those of previous studies, whereas the Ky – free type with Ca – poor garnet yielded slightly lower P – T conditions (3.1 – 3.4 GPa and 950 – 990 °C) than the other two types. The observed chemical variation of garnet is probably due to the di ff erence in origins, whereby, according to our new results and previous fi ndings, the Ky – bearing eclogite was derived from plagioclase – bearing crustal gabbro, whereas the Ky – free eclogite with Ca – rich garnet was derived from a crystal cumulate possibly in the mantle wedge. In the Ky – free eclogite samples with Ca – poor garnet, chemical compositions of garnet and omphacite are di ff erent from those in the other Ky – free samples, and those samples with Ca – poor garnet would have a di ff erent origin from the others. One of the Ky – free type with Ca – poor garnet retains garnet grains with chemical zonings probably created during the prograde history, although the eclogite underwent the extremely high temperature (~ 1000 °C) metamorphism. Calculated di ff usion distances in garnet reach 0.5 mm during 2 million years, even if we adopted a low value of di ff usion coe ffi cient data. Thus, the residence time of the eclogite at the peak meatamorphic conditions would have been shorter than at least 2 million years. The subsequent decompression and cooling after the peak metamorphism were also probably very fast to avoid the chemical homogenization of garnet.","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":"68832236","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":"Determination of orientational ordering of hydroxy groups in kulanite between 120-353 K using single-crystal X-ray diffraction","authors":"R. Yamane, M. Tokuda, K. Sugiyama","doi":"10.2465/jmps.220701","DOIUrl":"https://doi.org/10.2465/jmps.220701","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":"68832383","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}
Mineralogical investigation of platinum – group minerals (PGM) from the placer deposit in northwestern Hokkaido, Japan, was conducted at six rivers and two coasts covering an area of 70 km north – south and 30 km east – west: the Moshosanbetsu River (M), the Shosanbetsu River (S), the Ainusawa River (A), the Tomamae coast (T), the Obira coast (OC), the Kamikinenbetsusawa River (K), the Obirashibe River (OR), and the Numatapon River (N) from north to south. Details of the major PGM grain and the occurrence of small but diverse PGM inclusions were revealed in this study. Among diverse PGM inclusions, Cu 3 Pt mineral was discovered in PGM placer from the coast of Tomamae town, and it has been approved as a new mineral, tomamaeite, named after the type locality, by the International Mineralogical Association, the Commission on New Minerals, Nomenclature and Classi fi cation (IMA – CNMNC). Later, tomamaeite was also discovered in fi ve localities. Tomamaeite occurs in Pt – Fe(Cu) alloys such as tulameenite, ferronickelplatinum, tetraferroplatinum, and hongshiite as an anhedral particle with a size of less than 20 µm. Tomamaeite is an opaque mineral and has metallic luster with a pale mist white color in re fl ected light. The hardness of tomamaeite has yet to be determined, although it is estimated to be ~ 3½ from comparison with compositionally related minerals and the calculated density is 12.4 g·cm − 3 using the empirical formula and powder X – ray di ff raction data. The empirical formula of tomamaeite calculated on the basis of 4 apfu is (Cu 3.01
{"title":"Platinum–group minerals in the placer deposit in northwestern Hokkaido, Japan: description of a new mineral, tomamaeite","authors":"D. Nishio–Hamane, Katsuyuki Saito","doi":"10.2465/jmps.220309","DOIUrl":"https://doi.org/10.2465/jmps.220309","url":null,"abstract":"Mineralogical investigation of platinum – group minerals (PGM) from the placer deposit in northwestern Hokkaido, Japan, was conducted at six rivers and two coasts covering an area of 70 km north – south and 30 km east – west: the Moshosanbetsu River (M), the Shosanbetsu River (S), the Ainusawa River (A), the Tomamae coast (T), the Obira coast (OC), the Kamikinenbetsusawa River (K), the Obirashibe River (OR), and the Numatapon River (N) from north to south. Details of the major PGM grain and the occurrence of small but diverse PGM inclusions were revealed in this study. Among diverse PGM inclusions, Cu 3 Pt mineral was discovered in PGM placer from the coast of Tomamae town, and it has been approved as a new mineral, tomamaeite, named after the type locality, by the International Mineralogical Association, the Commission on New Minerals, Nomenclature and Classi fi cation (IMA – CNMNC). Later, tomamaeite was also discovered in fi ve localities. Tomamaeite occurs in Pt – Fe(Cu) alloys such as tulameenite, ferronickelplatinum, tetraferroplatinum, and hongshiite as an anhedral particle with a size of less than 20 µm. Tomamaeite is an opaque mineral and has metallic luster with a pale mist white color in re fl ected light. The hardness of tomamaeite has yet to be determined, although it is estimated to be ~ 3½ from comparison with compositionally related minerals and the calculated density is 12.4 g·cm − 3 using the empirical formula and powder X – ray di ff raction data. The empirical formula of tomamaeite calculated on the basis of 4 apfu is (Cu 3.01","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":"68832257","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}
Daiki Fukuyama, K. Shinoda, Daigo Takagi, Yasuhiro Kobayashi
The compositional dependence of the intensity and electric fi eld gradient (EFG) tensors for Fe 2+ at the M 1 sites, Fe 2+ at the M 2 sites, and Fe 3+ at the M 1 sites in Ca – rich pyroxene were obtained from Mössbauer spectra of crystallographically oriented single – crystal thin sections of four Ca – rich natural pyroxenes. Components of the intensity tensor ( I XX , I YY , I XY , and I ZZ ) for Fe 2+ at the M 1 sites in Wo 50 Ca – rich pyroxene were almost the same; the averages of the I XX , I YY , I XY , and I ZZ components were 0.342, 0.477, 0.039, and 0.681, respectively. Intensity tensor for Fe 2+ at the M 1 sites of Wo 40 Ca – rich pyroxene was di ff erent from the Wo 50 . Whereas principal axes of EFG tensors for Fe 2+ at the M 1 sites of Wo 50 pyroxenes had the same direction, principal axes of V XX and V YY of EFG of Wo 40 had di ff erent directions from that from Wo 50 . The di ff erence of intensity and EFG tensors between Wo 50 and Wo 40 suggests that the intensity and EFG tensors for Fe 2+ at M 1 sites are dependent on the Ca contents and are independent of Fe contents. Some intensity and EFG tensors for Fe 2+ at the M 2 sites and Fe 3+ at the M 1 sites in Ca – rich pyroxene were also obtained. However, the compositional dependence of the intensity and EFG tensors has yet to be clari fi ed, because the number of examples is insu ffi
{"title":"Compositional dependence of intensity and electric field gradient tensors for Fe2+ at the M1 site in Ca–rich pyroxene by single crystal Mössbauer spectroscopy","authors":"Daiki Fukuyama, K. Shinoda, Daigo Takagi, Yasuhiro Kobayashi","doi":"10.2465/jmps.220506","DOIUrl":"https://doi.org/10.2465/jmps.220506","url":null,"abstract":"The compositional dependence of the intensity and electric fi eld gradient (EFG) tensors for Fe 2+ at the M 1 sites, Fe 2+ at the M 2 sites, and Fe 3+ at the M 1 sites in Ca – rich pyroxene were obtained from Mössbauer spectra of crystallographically oriented single – crystal thin sections of four Ca – rich natural pyroxenes. Components of the intensity tensor ( I XX , I YY , I XY , and I ZZ ) for Fe 2+ at the M 1 sites in Wo 50 Ca – rich pyroxene were almost the same; the averages of the I XX , I YY , I XY , and I ZZ components were 0.342, 0.477, 0.039, and 0.681, respectively. Intensity tensor for Fe 2+ at the M 1 sites of Wo 40 Ca – rich pyroxene was di ff erent from the Wo 50 . Whereas principal axes of EFG tensors for Fe 2+ at the M 1 sites of Wo 50 pyroxenes had the same direction, principal axes of V XX and V YY of EFG of Wo 40 had di ff erent directions from that from Wo 50 . The di ff erence of intensity and EFG tensors between Wo 50 and Wo 40 suggests that the intensity and EFG tensors for Fe 2+ at M 1 sites are dependent on the Ca contents and are independent of Fe contents. Some intensity and EFG tensors for Fe 2+ at the M 2 sites and Fe 3+ at the M 1 sites in Ca – rich pyroxene were also obtained. However, the compositional dependence of the intensity and EFG tensors has yet to be clari fi ed, because the number of examples is insu ffi","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":"68832342","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}
To determine the phase boundary between diaspore ( α – AlOOH) and δ – AlOOH, in situ X – ray di ff raction experiments were carried out using a multi – anvil high – pressure apparatus and synchrotron X – ray. The stability of each phase was determined by observing the change in powder X – ray di ff raction patterns. The equilibrium phase boundary is described by the formula P (GPa) = 12.2 (±4.9) + 0.0027 (±0.0044) × T (K). The boundary determined in this study is located at a lower pressure than that estimated by previous quenching experimental studies.
{"title":"In situ X–ray diffraction study of the phase boundary between diaspore and δ–AlOOH","authors":"A. Suzuki","doi":"10.2465/jmps.211215","DOIUrl":"https://doi.org/10.2465/jmps.211215","url":null,"abstract":"To determine the phase boundary between diaspore ( α – AlOOH) and δ – AlOOH, in situ X – ray di ff raction experiments were carried out using a multi – anvil high – pressure apparatus and synchrotron X – ray. The stability of each phase was determined by observing the change in powder X – ray di ff raction patterns. The equilibrium phase boundary is described by the formula P (GPa) = 12.2 (±4.9) + 0.0027 (±0.0044) × T (K). The boundary determined in this study is located at a lower pressure than that estimated by previous quenching experimental studies.","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"7 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68831892","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}
Takehiro Hirayama, T. Shibata, M. Yoshikawa, Khadidja Abbou-Kebir, K. Kimura, Y. Osanai, K. Das, Y. Hayasaka, K. Takemura
Granitic and gabbroic xenoliths have been found within dacitic lavas in the Hime – shima volcanic group (HVG) of northeastern Kyushu, Japan. The HVG is located near the boundary between the Ryoke and Sangun belts, suggesting that the HVG and associated crustal xenoliths may provide insights into the subsurface distribution of the Ryoke and Sangun belts in Kyushu. This study focuses on xenoliths obtained from the coastal boulders near the Kane Lava of the HVG. The HVG xenoliths consist of gabbro, gabbroic diorite, amphibolite, gneiss, basaltic andesite, and tu ff aceous sandstone, with the latter two types resembling those found in the basement rocks of the HVG. The gabbroic xenoliths are geochemically similar to gabbros in the Ryoke belt. The U – Pb dating for zircon in the gneiss xenoliths yielded a metamorphic age of ~ 111 Ma with Th/U values <0.1, similar to the age obtained for metamorphic rocks in or of the Ryoke belt. The new data presented in this study indicate that the xenoliths in the HVG were derived from basement units associated with the Ryoke belt, which in turn, means that the HVG is tectonically underlain by the Ryoke belt. This also suggests that the Ryoke belt extends further north in Kyushu than was previously considered, as implied by the presence of this belt directly below the HVG.
{"title":"Origin of xenoliths within the Hime–shima volcanic group, Kyushu, southwestern Japan Arc","authors":"Takehiro Hirayama, T. Shibata, M. Yoshikawa, Khadidja Abbou-Kebir, K. Kimura, Y. Osanai, K. Das, Y. Hayasaka, K. Takemura","doi":"10.2465/jmps.211217b","DOIUrl":"https://doi.org/10.2465/jmps.211217b","url":null,"abstract":"Granitic and gabbroic xenoliths have been found within dacitic lavas in the Hime – shima volcanic group (HVG) of northeastern Kyushu, Japan. The HVG is located near the boundary between the Ryoke and Sangun belts, suggesting that the HVG and associated crustal xenoliths may provide insights into the subsurface distribution of the Ryoke and Sangun belts in Kyushu. This study focuses on xenoliths obtained from the coastal boulders near the Kane Lava of the HVG. The HVG xenoliths consist of gabbro, gabbroic diorite, amphibolite, gneiss, basaltic andesite, and tu ff aceous sandstone, with the latter two types resembling those found in the basement rocks of the HVG. The gabbroic xenoliths are geochemically similar to gabbros in the Ryoke belt. The U – Pb dating for zircon in the gneiss xenoliths yielded a metamorphic age of ~ 111 Ma with Th/U values <0.1, similar to the age obtained for metamorphic rocks in or of the Ryoke belt. The new data presented in this study indicate that the xenoliths in the HVG were derived from basement units associated with the Ryoke belt, which in turn, means that the HVG is tectonically underlain by the Ryoke belt. This also suggests that the Ryoke belt extends further north in Kyushu than was previously considered, as implied by the presence of this belt directly below the HVG.","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":"68832093","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 metamorphic complex from the Mt. Tenzan area in northern Kyushu consists mainly of ma fi c rocks with small amounts of siliceous, calc – silicate, and ultrama fi c rocks. These lithofacies can be recognized as an ophiolitic complex. Metamorphosed ma fi c rocks are divided into two types, amphibolites I and II, which are probably derived from supracrustal and intrusive rocks, respectively. The geochemical data of both amphibolites plotted within the fi eld between mid – ocean ridge and island arc basalts; such geochemical features resemble those of back – arc basin basalts. As the metamorphic complex was intruded by Cretaceous granitoids, protoliths of the complex could have been formed prior to the Cretaceous. The protolith lithofacies assemblage and geochemical constraints of the Tenzan metamorphic complex indicate the correlation with the Yakuno ophiolite rather than the Oeyama ophiolite.
{"title":"Geochemical characteristics of an ophiolitic complex from Mt. Tenzan area, Saga Prefecture, northern Kyushu","authors":"Yusaku Tanaka, K. Eshima, M. Owada","doi":"10.2465/jmps.210831","DOIUrl":"https://doi.org/10.2465/jmps.210831","url":null,"abstract":"The metamorphic complex from the Mt. Tenzan area in northern Kyushu consists mainly of ma fi c rocks with small amounts of siliceous, calc – silicate, and ultrama fi c rocks. These lithofacies can be recognized as an ophiolitic complex. Metamorphosed ma fi c rocks are divided into two types, amphibolites I and II, which are probably derived from supracrustal and intrusive rocks, respectively. The geochemical data of both amphibolites plotted within the fi eld between mid – ocean ridge and island arc basalts; such geochemical features resemble those of back – arc basin basalts. As the metamorphic complex was intruded by Cretaceous granitoids, protoliths of the complex could have been formed prior to the Cretaceous. The protolith lithofacies assemblage and geochemical constraints of the Tenzan metamorphic complex indicate the correlation with the Yakuno ophiolite rather than the Oeyama ophiolite.","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":"68832163","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}
Yoshihiro Nakamura, Koji U. Takahashi, J. Hosoi, H. Hara
A new type of compact deep – UV micro – Raman spectroscopy system was developed with a single monochromator, front – illuminated cooled charge – coupled device, and 266 nm nanosecond pulsed laser to overcome laser – induced fl uorescence from surrounding minerals and organic material. Deep – UV micro – Raman spectroscopy is particularly useful in analyzing the fl uorescence – free Raman spectra of dispersed low – maturity carbonaceous material and coal, although deep – UV excitation lasers may cause serious degradation and laser – induced heating of the sample surface, especially in microanalysis. The laser – induced damage threshold for fully ordered graphite and coal (VR r = ~ 0.5%) was assessed to facilitate the acquisition of accurate Raman spectra with a spot size of ~ 1 µm. For fully ordered graphite, there was no serious degradation of the sample surface with an energy fl uence of 0.10 – 2.50 J cm − 2 . Some sample surfaces became black at higher fl uences of 1.96 – 2.50 J cm − 2 , suggesting irreversible damage by deep – UV lasers. The Raman shift of the G band after measurement involves a downshift of 1.7 – 7.4 cm − 1 relative to other spectra obtained at low laser fl uences of <0.34 J cm − 2 . The G band full width at half maximum (FWHM) also increased with increasing laser fl uence. Serious degradation of polished coal surfaces occurs at even lower laser fl uences of 0.34 – 2.50 J cm − 2 . The degree of change in Raman parameters such as the D and G band FWHM depends on the laser fl uence during measurements. Heating and damage by a deep – UV laser is greater than that by visible lasers. Laser fl uences of <0.16 and 0.34 J cm − 2 are required for accurate Raman analyses of dispersed carbonaceous material in sedimentary rocks and fully ordered graphite in metasediment, respectively
{"title":"Determination of the laser–induced damage threshold for graphite and coal with deep–UV micro–Raman spectroscopy","authors":"Yoshihiro Nakamura, Koji U. Takahashi, J. Hosoi, H. Hara","doi":"10.2465/jmps.220316","DOIUrl":"https://doi.org/10.2465/jmps.220316","url":null,"abstract":"A new type of compact deep – UV micro – Raman spectroscopy system was developed with a single monochromator, front – illuminated cooled charge – coupled device, and 266 nm nanosecond pulsed laser to overcome laser – induced fl uorescence from surrounding minerals and organic material. Deep – UV micro – Raman spectroscopy is particularly useful in analyzing the fl uorescence – free Raman spectra of dispersed low – maturity carbonaceous material and coal, although deep – UV excitation lasers may cause serious degradation and laser – induced heating of the sample surface, especially in microanalysis. The laser – induced damage threshold for fully ordered graphite and coal (VR r = ~ 0.5%) was assessed to facilitate the acquisition of accurate Raman spectra with a spot size of ~ 1 µm. For fully ordered graphite, there was no serious degradation of the sample surface with an energy fl uence of 0.10 – 2.50 J cm − 2 . Some sample surfaces became black at higher fl uences of 1.96 – 2.50 J cm − 2 , suggesting irreversible damage by deep – UV lasers. The Raman shift of the G band after measurement involves a downshift of 1.7 – 7.4 cm − 1 relative to other spectra obtained at low laser fl uences of <0.34 J cm − 2 . The G band full width at half maximum (FWHM) also increased with increasing laser fl uence. Serious degradation of polished coal surfaces occurs at even lower laser fl uences of 0.34 – 2.50 J cm − 2 . The degree of change in Raman parameters such as the D and G band FWHM depends on the laser fl uence during measurements. Heating and damage by a deep – UV laser is greater than that by visible lasers. Laser fl uences of <0.16 and 0.34 J cm − 2 are required for accurate Raman analyses of dispersed carbonaceous material in sedimentary rocks and fully ordered graphite in metasediment, respectively","PeriodicalId":51093,"journal":{"name":"Journal of Mineralogical and Petrological Sciences","volume":"23 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68832323","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":"Serpentinization of forsterite under hydrothermal conditions and controlled synthesis of lizardite","authors":"Zhiqiang Zhou, Hongjuan Sun, T. Peng","doi":"10.2465/jmps.220630b","DOIUrl":"https://doi.org/10.2465/jmps.220630b","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":"68832378","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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