start-ver=1.4 cd-journal=joma no-vol=35 cd-vols= no-issue=2 article-no= start-page=159 end-page=169 dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=20260811 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An interdisciplinary approach to sampling hard rock cores of the oceanic crust for microbiological and biogeochemical research en-subtitle= kn-subtitle= en-abstract= kn-abstract=Studying life in the deep, rocky subseafloor involves many layers of technological and methodological challenges, and each drilling project or expedition must make a series of choices to address these challenges. We report on the workflow for sampling hard rock cores for microbiological and biogeochemical research that was developed and optimized during International Ocean Discovery Program (IODP) Expedition 399. All steps of the workflow, including selection of the sample and its shipboard homogenization and subsampling for specific analyses, were designed to maximize the potential for interdisciplinary collaborations and syntheses of results. Furthermore, multiple strategies to minimize and detect potential microbial and organic chemical contamination of the core samples were employed, including the shipboard detection of a fluorescent chemical tracer pumped into the drill fluid. Contamination tracer levels were detectable on the exterior surfaces of the core but absent in the homogenized interiors of most core samples. Based on the experiences and preliminary results of this expedition, recommendations for processing samples on future expeditions are presented. en-copyright= kn-copyright= en-aut-name=BrazeltonWilliam J. en-aut-sei=Brazelton en-aut-mei=William J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=CavazosOscar en-aut-sei=Cavazos en-aut-mei=Oscar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=RobareJordyn A. en-aut-sei=Robare en-aut-mei=Jordyn A. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SouthamGordon en-aut-sei=Southam en-aut-mei=Gordon kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SuhonenJohanna en-aut-sei=Suhonen en-aut-mei=Johanna kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=WangFengping en-aut-sei=Wang en-aut-mei=Fengping kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=LangSusan Q. en-aut-sei=Lang en-aut-mei=Susan Q. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=McCaigAndrew en-aut-sei=McCaig en-aut-mei=Andrew kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=BlumPeter en-aut-sei=Blum en-aut-mei=Peter kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=AbeNatsue en-aut-sei=Abe en-aut-mei=Natsue kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=ColtatRémi en-aut-sei=Coltat en-aut-mei=Rémi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=DeansJeremy R. en-aut-sei=Deans en-aut-mei=Jeremy R. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=DickersonKristin L. en-aut-sei=Dickerson en-aut-mei=Kristin L. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=GodardMarguerite en-aut-sei=Godard en-aut-mei=Marguerite kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=JohnBarbara E. en-aut-sei=John en-aut-mei=Barbara E. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=KleinFrieder en-aut-sei=Klein en-aut-mei=Frieder kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=KuehnRebecca en-aut-sei=Kuehn en-aut-mei=Rebecca kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=LinKuan-Yu en-aut-sei=Lin en-aut-mei=Kuan-Yu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=LissenbergC. Johan en-aut-sei=Lissenberg en-aut-mei=C. Johan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=LiuHaiyang en-aut-sei=Liu en-aut-mei=Haiyang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= en-aut-name=LopesEthan L. en-aut-sei=Lopes en-aut-mei=Ethan L. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=21 ORCID= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=22 ORCID= en-aut-name=ParsonsAndrew J. en-aut-sei=Parsons en-aut-mei=Andrew J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=23 ORCID= en-aut-name=PathakVamdev en-aut-sei=Pathak en-aut-mei=Vamdev kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=24 ORCID= en-aut-name=ReaganMark K. en-aut-sei=Reagan en-aut-mei=Mark K. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=25 ORCID= en-aut-name=WheatC. Geoffrey en-aut-sei=Wheat en-aut-mei=C. Geoffrey kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=26 ORCID= affil-num=1 en-affil=School of Biological Sciences, University of Utah kn-affil= affil-num=2 en-affil=International Ocean Discovery Program, Texas A&M University kn-affil= affil-num=3 en-affil=School of Molecular Sciences, Arizona State University kn-affil= affil-num=4 en-affil=School of the Environment and Sustainable Minerals Institute, University of Queensland kn-affil= affil-num=5 en-affil=International Ocean Discovery Program, Texas A&M University kn-affil= affil-num=6 en-affil=School of Oceanography, Shanghai Jiao Tong University kn-affil= affil-num=7 en-affil=Dept. of Geol. and Geophys., Woods Hole Oceanographic Institution kn-affil= affil-num=8 en-affil=School of Earth and Environment, University of Leeds kn-affil= affil-num=9 en-affil=International Ocean Discovery Program, Texas A&M University kn-affil= affil-num=10 en-affil=Japan Agency for Marine-Earth Science and Technology kn-affil= affil-num=11 en-affil=ISTO, UMR 7327, Univ. Orleans, CNRS, BRGM, OSUC kn-affil= affil-num=12 en-affil=School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi kn-affil= affil-num=13 en-affil=Dept. of Earth and Planetary Sciences, University of California kn-affil= affil-num=14 en-affil=Geosciences Montpellier, CNRS, University of Montpellier kn-affil= affil-num=15 en-affil=Dept. of Geology and Geophysics, University of Wyoming, Laramie kn-affil= affil-num=16 en-affil=Dept. of Geol. and Geophys., Woods Hole Oceanographic Institution, kn-affil= affil-num=17 en-affil=Institute of Geosciences and Geography, Martin Luther University Halle-Wittenberg kn-affil= affil-num=18 en-affil=Electron Microscopy Core Facility, Purdue University kn-affil= affil-num=19 en-affil=School of Earth and Environmental Sciences, Cardiff University kn-affil= affil-num=20 en-affil=Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences kn-affil= affil-num=21 en-affil=Dept. of Geophysics, Stanford University kn-affil= affil-num=22 en-affil=Dept. Earth Sciences, Okayama University kn-affil= affil-num=23 en-affil=School of Geography, Earth and Environmental Sciences, University of Plymouth kn-affil= affil-num=24 en-affil=Dept. Geology, Central University of Punjab kn-affil= affil-num=25 en-affil=Dept. of Earth and Environmental Sciences, University of Iowa kn-affil= affil-num=26 en-affil=Global Undersea Research Unit, University of Alaska Fairbanks kn-affil= END start-ver=1.4 cd-journal=joma no-vol=542-543 cd-vols= no-issue= article-no= start-page=108716 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=20261115 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Serpentinization parageneses controlled by lithological variations among olivine gabbro and peridotite from the Atlantis Massif, Mid-Atlantic Ridge en-subtitle= kn-subtitle= en-abstract= kn-abstract=Serpentinization of olivine impacts the geochemical and ecological environment via molecular hydrogen production, promoted by iron oxidation to form magnetite and ferric iron in serpentine. Previous studies suggested that serpentinization proceeds with various reactions and the extent of iron oxidation is variable depending on the reaction pathways. To examine the effect of lithological variation on reactions at an incipient stage of serpentinization, we carried out microscopic observations, electron-probe analyses, and Raman spectroscopy of serpentine veins cutting olivine in gabbroic rocks and peridotites from the Atlantis Massif, Mid-Atlantic Ridge. The results indicate that the serpentine veins in the proximity of olivine dominantly comprise lizardite mixed with variable minor phases or components depending on igneous lithology: brucite in peridotites, troctolites, and primitive olivine gabbros; cronstedtite-bearing serpentine, commonly without brucite, in some troctolites and slightly evolved olivine gabbros; and neither brucite nor cronstedtite component in evolved olivine gabbros. This suggests that incipient-stage serpentinization paragenesis is dominantly controlled by silica activity reflecting lithological variation. In addition to magnetite, the formation of cronstedtite in gabbroic rocks has the potential to produce hydrogen. The presence or absence of brucite and cronstedtite could affect the timing and magnitude of iron oxidation and hydrogen production during serpentinization. Considering the predominance of gabbroic rocks in the lower oceanic crust, the variation in incipient-stage serpentinization paragenesis in gabbroic rocks may have an impact on the redox state and ecological environment around the (sub)seafloor. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KazumataShun en-aut-sei=Kazumata en-aut-mei=Shun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KleinFrieder en-aut-sei=Klein en-aut-mei=Frieder kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=3 en-affil=Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution kn-affil= en-keyword=Serpentinization kn-keyword=Serpentinization en-keyword=Brucite kn-keyword=Brucite en-keyword=Cronstedtite kn-keyword=Cronstedtite en-keyword=Olivine gabbro kn-keyword=Olivine gabbro en-keyword=Peridotite kn-keyword=Peridotite en-keyword=Atlantis Massif kn-keyword=Atlantis Massif END start-ver=1.4 cd-journal=joma no-vol=32 cd-vols= no-issue=1 article-no= start-page=9 end-page=19 dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=20260331 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Petrological study of Sue ware from the Sabukaze kiln site, Okayama Prefecture kn-title=寒風古窯跡群須恵器の岩石学的研究 en-subtitle= kn-subtitle= en-abstract= kn-abstract=　The Sabukaze kiln site, a representative ancient tunnel-kiln site in the Kibi region, worked during the Asuka period (from early 7th century to early 8th century) to produce Sue ware including jars, cups, coffins, and ornamental tiles. To determine the provenance of the materials used for the Sue ware, we carried out petrological analyses of 13 Sue sherds, including optical microscopy, X-ray diffractometry, X-ray fluorescence spectroscopy, Raman spectroscopy, and electron-probe analysis. In spite of the difference of production time, all the Sue sherds show close similarities in modal proportion of mineral inclusions with dominant quartz and feldspar, and minor volcanic glass, in chemical compositions of feldspar and interstitial matrix, and in whole-sherd chemical composition. These similarities suggest that the paste materials of the Sabukaze Sue ware were commonly derived from weathered rhyolitic rocks and obtained from the same or neighboring mining site(s) located near the kiln site. en-copyright= kn-copyright= en-aut-name=ANAMITaiji en-aut-sei=ANAMI en-aut-mei=Taiji kn-aut-name=阿南太士 kn-aut-sei=阿南 kn-aut-mei=太士 aut-affil-num=1 ORCID= en-aut-name=NOZAKAToshio en-aut-sei=NOZAKA en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=2 ORCID= en-aut-name=KIMURAOsamu en-aut-sei=KIMURA en-aut-mei=Osamu kn-aut-name=木村理 kn-aut-sei=木村 kn-aut-mei=理 aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil=岡山大学大学院環境生命自然科学研究科 affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil=岡山大学学術研究院環境生命自然科学学域 affil-num=3 en-affil=Department of Archaeology, Osaka University kn-affil=大阪大学考古学研究室 en-keyword=Sabukaze kiln site kn-keyword=Sabukaze kiln site en-keyword=Sue ware kn-keyword=Sue ware en-keyword=provenance kn-keyword=provenance en-keyword=petrology kn-keyword=petrology END start-ver=1.4 cd-journal=joma no-vol=70 cd-vols= no-issue= article-no= start-page=105566 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=202604 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A semi-quantitative archaeothermometer based on feldspar and volcanic glass compositions in ancient ceramics from the Kibi region, Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=In this study, we analyzed the chemical compositions of feldspar and volcanic glass clasts in haniwa from kofuns and Sue ware from the Sabukaze kiln site, both in the Kibi region, southwestern Japan, to estimate the thermal conditions of ceramic firing in the 5th–8th centuries CE. Based on the coexistence of molten and unmolten feldspar rims, the solidus temperatures were estimated at ∼ 1050°C–1150°C for haniwa and ∼ 1150°C–1200°C for Sue ware. Volcanic glass compositions changed systematically during firing, showing increases in K2O and decreases in Na2O. From these observations, we propose a semi-quantitative archaeothermometer using variations in the K/Na molar ratio of volcanic glass within a ceramic matrix. This approach can be applied to investigate the development of kiln-firing in the Kibi region, the existence of haniwa potters employing different firing methods, variation in heat input for producing Sue vessels of differing sizes or functions, and temperature-controlled practices in Sue ware production. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OhbayashiNaoya en-aut-sei=Ohbayashi en-aut-mei=Naoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TodaYuki en-aut-sei=Toda en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AnamiTaiji en-aut-sei=Anami en-aut-mei=Taiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SugiuraKanako en-aut-sei=Sugiura en-aut-mei=Kanako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NozakiTakahiro en-aut-sei=Nozaki en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KimuraOsamu en-aut-sei=Kimura en-aut-mei=Osamu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MatsumotoNaoko en-aut-sei=Matsumoto en-aut-mei=Naoko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=SeikeAkira en-aut-sei=Seike en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=3 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=4 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=5 en-affil=Department of Archaeology, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=7 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=8 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=9 en-affil=Department of Archaeology, Okayama University kn-affil= en-keyword=Haniwa kn-keyword=Haniwa en-keyword=Sue ware kn-keyword=Sue ware en-keyword=Firing temperature kn-keyword=Firing temperature en-keyword=Kibi kn-keyword=Kibi en-keyword=Japan kn-keyword=Japan END start-ver=1.4 cd-journal=joma no-vol=60 cd-vols= no-issue= article-no= start-page=104813 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=202412 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Petrological characterization for material provenance of haniwa earthenware from mounded tombs in the Kibi region, Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=To determine the provenance of the materials used in the production of haniwa earthenware unearthed from mounded tombs (kofun) in the Kibi region (modern Okayama Prefecture) during the Kofun period (late 3rd – 6th century CE) of Japan, we carried out petrological analyses of haniwa sherds, including optical microscopy, X-ray diffractometry, X-ray fluorescence spectroscopy, and electron-probe analysis. The 25 haniwa sherds analyzed from 12 representative mounded tombs are composed of mineral and rock inclusions with variable grain size set in a clay matrix. The dominant inclusions are quartz, K-feldspar, and plagioclase, associated with minor amounts of amphibole, volcanic glass, and granitic rocks in all the haniwa sherds, and small amounts of hornfels, quartz rock, and accessory minerals, including mica, ilmenite, and chromite, in some of the sherds. Amphibole and plagioclase have compositional variations indicative of the mixing of tephra and granitic components. The compositions of volcanic glass inclusions are similar to those of the Aira-Tanzawa and Kikai-Akahoya tephras widely distributed in southwestern Japan. Bulk chemical compositions show magmatic differentiation trends, which are variable between individual tombs. From these results, it is concluded that the paste materials of haniwa in the Kibi region were commonly derived from weathered granitic rocks mixed with minor amounts of three widespread tephras. The variations of chemical and mineralogical compositions are probably the reflection of local geologic settings, suggesting the presence of specific mining sites of paste materials around each tomb. The mining sites could be located at the bases of hills of granitic rocks covered by widespread tephras and in some cases, near the flood plain of big river systems. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OhbayashiNaoya en-aut-sei=Ohbayashi en-aut-mei=Naoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TodaYuki en-aut-sei=Toda en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SugiuraKanako en-aut-sei=Sugiura en-aut-mei=Kanako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NozakiTakahiro en-aut-sei=Nozaki en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KimuraOsamu en-aut-sei=Kimura en-aut-mei=Osamu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MatsumotoNaoko en-aut-sei=Matsumoto en-aut-mei=Naoko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=SeikeAkira en-aut-sei=Seike en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=3 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=4 en-affil=Department of Archaeology, Okayama University kn-affil= affil-num=5 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=7 en-affil=Research Institute for the Dynamics of Civilizations, Okayama University kn-affil= affil-num=8 en-affil=Department of Archaeology, Okayama University kn-affil= en-keyword=Haniwa kn-keyword=Haniwa en-keyword=Paste material kn-keyword=Paste material en-keyword=Provenance kn-keyword=Provenance en-keyword=Kofun kn-keyword=Kofun en-keyword=Kibi kn-keyword=Kibi en-keyword=Japan kn-keyword=Japan END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=1 article-no= start-page=1 end-page=12 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240331 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Petrological characteristics of the stone chamber of Tobiotsuka Kofun, Okayama Prefecture kn-title=鳶尾塚古墳の石室石材の岩石学的特徴 en-subtitle= kn-subtitle= en-abstract= kn-abstract=　Tobiotsuka Kofun, a tumulus built on the Misu Hills in the Kofun period, has a horizontal stone chamber made of huge stone blocks with a width up to 2 meters or more. To specify the source of the stone blocks, we carried out the measurement of magnetic susceptibility, petrographic observation, and chemical analysis of minerals. The stones are amphibole-biotite granite with phenocrystic large grains of K-feldspar. The back-wall stone of the chamber has higher magnetic susceptibility than ceiling and side-wall stones, which probably results from a higher amount of magnetite formed by the alteration of biotite in the back-wall stone. Furthermore, the back-wall stone is different from ceiling stone in that it has lower XMg [Mg/(Mg + Fe) mole ratio], lower Al, Ti, and Na + K contents and higher Si contents of amphibole, higher XMg of biotite, and shows a tendency to have higher Na (albite component) contents at rims of plagioclase crystals and lower Ti contents of zircon. These characteristics of the back-wall stone are similar to those of granite exposed in the Koshinzan area about 2 km northeast of Tobiotsuka Kofun, whereas the ceiling and side-wall stones are similar to granite outcrops in the vicinity of Tobiotsuka Kofun, e.g., in the Midoriyama area. It is concluded that the quarry for the back-wall was located at a different place from that for the ceiling and side-wall stones. en-copyright= kn-copyright= en-aut-name=KANEKOTakahiro en-aut-sei=KANEKO en-aut-mei=Takahiro kn-aut-name=金子峻大 kn-aut-sei=金子 kn-aut-mei=峻大 aut-affil-num=1 ORCID= en-aut-name=NOZAKAToshio en-aut-sei=NOZAKA en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=2 ORCID= en-aut-name=SEIKEAkira en-aut-sei=SEIKE en-aut-mei=Akira kn-aut-name=清家章 kn-aut-sei=清家 kn-aut-mei=章 aut-affil-num=3 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil=岡山大学大学院自然科学研究科 affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil=岡山大学学術研究院環境生命自然科学学域 affil-num=3 en-affil=Department of Archaeology, Okayama University kn-affil=岡山大学学術研究院社会文化科学学域 en-keyword=Tobiotsuka Kofun kn-keyword=Tobiotsuka Kofun en-keyword=stone chamber kn-keyword=stone chamber en-keyword=granite kn-keyword=granite END start-ver=1.4 cd-journal=joma no-vol=17 cd-vols= no-issue=1 article-no= start-page=1 end-page=5 dt-received= dt-revised= dt-accepted= dt-pub-year=2010 dt-pub=20101224 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=西南日本の熱変成超苦鉄質岩体中のかんらん石と輝石の組成変化に関する覚書 kn-title=A note on compositional variation of olivine and pyroxene in thermally metamorphosed ultramafic complexes from SW Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=This short article presents some diagrams showing the compositional variations of primary and metamorphic olivine, orthopyroxene and clinopyroxene in peridotites and serpentinites from thermally metamorphosed ultramafic complexes in SW Japan. In contrast to olivine, which shows a gradual change of chemical composition corresponding with metamorphic grade, orthopyroxene and clinopyroxene show clear differences in composition between primary and metamorphic phases. Compared with primary pyroxenes, even though their compositions could be variable depending on original rock composition, metamorphic orthopyroxene and metamorphic clinopyroxene is clearly deficient in Cr(2)O(3) and CaO, and in Cr(2)O(3) and Al(2)O(3), respectively. These characteristics are useful for the discrimination between the pyroxenes of different origin. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Department of Earth Sciences, Faculty of Science, Okayama University en-keyword=chemical composition kn-keyword=chemical composition en-keyword=olivine kn-keyword=olivine en-keyword=orthopyroxene kn-keyword=orthopyroxene en-keyword=clinopyroxene kn-keyword=clinopyroxene en-keyword=metaperidotite kn-keyword=metaperidotite END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue=1 article-no= start-page=1 end-page=8 dt-received= dt-revised= dt-accepted= dt-pub-year=1994 dt-pub=19940920 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Petrography of primary peridotites from the Ohsa-yama area, Okayama Prefecture en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ultramafic rocks exposed around Mt. Ohsa(= Ohsa-yama), Okayama prefecture, designated as "Ohsa-yama ultramafic body" all together, are one of the Alpine-type peridotites in the Sangun metamorphic belt. They are intensely serpentinized and locally suffered contact metamorphism by younger granitic intrusions. In a por-tion of the ohsa-yama body where it has been affected by the contact metamorphism, the constituent minerals, texture and structure of primary ultramafic rocks have been locally preserved. Petrographic studies revead that the primary ultramafic rocks of the ohsa-yama body consist domimantly of dunite and harzburgite possessing no obvious layering, and their constituent minerals are similar in composition to those of the Tari-Misaka and Ashidachi ultramafic bodies. These features indicate that unlike the Ochiai-Hokubo body, the Ohsa-yama ultra-mafic body belongs to the "massive group" of the Arai's (1980) classification. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=1 ORCID= en-aut-name=ShibataTsugio en-aut-sei=Shibata en-aut-mei=Tsugio kn-aut-name=柴田次夫 kn-aut-sei=柴田 kn-aut-mei=次夫 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Department of Earth Sicences, Faculty of Science Okayama University affil-num=2 en-affil= kn-affil=Department of Earth Sicences, Faculty of Science Okayama University en-keyword=petrography kn-keyword=petrography en-keyword=dunite kn-keyword=dunite en-keyword=harzburgite kn-keyword=harzburgite en-keyword=massive ultramafic body kn-keyword=massive ultramafic body END start-ver=1.4 cd-journal=joma no-vol=2 cd-vols= no-issue=1 article-no= start-page=1 end-page=12 dt-received= dt-revised= dt-accepted= dt-pub-year=1995 dt-pub=19950920 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mineral paragenesis in thermally metamorphosed serpentinites, Ohsa-yama, Okayama Prefecture en-subtitle= kn-subtitle= en-abstract= kn-abstract=The Ohsa-yama ultramafic body, which consists of several types of serpentinized peridotites, underwent contact metamorphism caused by a Cretaceous granite intrusion ; this metamorphism resulted in the formation of contact aureole, 1.5-2.0 km wide, around the granite intrusion, and produced progressive mineral changes in metaserpentinites toward the contact between the Ohsa-yama body and the granite intrusion. On the basis of analysis of mineral paragenetic relations, the Ohsa-yama ultramafic body can be divided into three zones with progressive changes in mineral assemblages as follows : Zone Ⅰ : serpentine ± chlorite ± brucite Zone Ⅱ : olivine + talc ± tremolite ± chlorite Zone Ⅲ : olivine + orthopyroxene ± tremolite ± spinel Zone Ⅰ corresponds to the parts unaffected by the thermal event, and Zones Ⅱ and Ⅲ correspond to the thermally metamorphosed parts of the Ohsa-yama body. The results obtained in this study are generally consistent with those of the previous studies on metamorphic peridotites from the Sangun and Muzuru zones. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=1 ORCID= en-aut-name=ShibataTsugio en-aut-sei=Shibata en-aut-mei=Tsugio kn-aut-name=柴田次夫 kn-aut-sei=柴田 kn-aut-mei=次夫 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Department of Earth Sciences, Faculty of Science Okayama University affil-num=2 en-affil= kn-affil=Department of Earth Sciences, Faculty of Science Okayama University en-keyword=peridotite kn-keyword=peridotite en-keyword=serpentinite kn-keyword=serpentinite en-keyword=thermal metamorphism kn-keyword=thermal metamorphism en-keyword=contact metamorphism kn-keyword=contact metamorphism END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue=1 article-no= start-page=33 end-page=40 dt-received= dt-revised= dt-accepted= dt-pub-year=1997 dt-pub=19970920 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Ferroglaucophane schist from the Ohsa-yama srea, Okayama Prefecture, Japan kn-title=岡山県大佐山地域に産するフェロ藍閃石片岩 en-subtitle= kn-subtitle= en-abstract= kn-abstract=A ferroglaucophane schist occurs in fault contact with serpentinites at the Ohsa-yama area, Southwest Japan. It consists of albite, ferroglaucophane and actinolite with small amounts of stilpnomelane, sphene, apatite and K-feldspar. Petrological studies reveal that the schist was originally igneous rock of felsic or intermediate composition and has suffered two stages of metamorphism : ferroglaucophane has been formed at the first stage and actinolite at the second stage. In a basic schist from the same outcrop that the ferroglaucophane schist occurs, tremolitic amphibole instead of alkali amphibole has been formed along with chlorite, phengite and albite. Such a difference in mineral association between the schists is ascribed to a difference in whole rock composition, particu-larly in Fe/Mg ratio. Some of the schists from th Ohsa-yama area characteristically contain glaucophane or ferroglaucophane and have low Fe2O3/FeO ratios, forming a striking contrast to the crossite schists that commonly occur in the so-called "Sangun metamorphic terrane". These facts suggest that the alkali amphiboles of the Ohsa-yama schists were formed under higher P/T and more reducing conditions than those of the regional metamrphic rocks. On the other hand, development of the second-stage actinolite in the ferroglaucophane schist is consistent with the meta-morphic parageneses of greenschists from adjacent areas. Consequently the ferroglaucophane schist is considered one of the tectonic blocks that were captured by mobile serpentinites and have suffered the regional metamor-phism after the emplacement of the serpentinites into the present geologic position. en-copyright= kn-copyright= en-aut-name=NozakaToshio en-aut-sei=Nozaka en-aut-mei=Toshio kn-aut-name=野坂俊夫 kn-aut-sei=野坂 kn-aut-mei=俊夫 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学理学部地球科学科 en-keyword=ferroglaucophane kn-keyword=ferroglaucophane en-keyword=petrology kn-keyword=petrology en-keyword=tectonic block kn-keyword=tectonic block en-keyword=serpentinite kn-keyword=serpentinite en-keyword=high P/T metamorphism, kn-keyword=high P/T metamorphism, en-keyword=Ohsa-yama kn-keyword=Ohsa-yama en-keyword=Sangun metamorphic terrane kn-keyword=Sangun metamorphic terrane en-keyword=Southwest Japan kn-keyword=Southwest Japan END