{"created":"2023-06-20T15:28:42.898604+00:00","id":8205,"links":{},"metadata":{"_buckets":{"deposit":"63116cfb-4a8d-4b29-a33d-8c4d1b87944d"},"_deposit":{"created_by":12,"id":"8205","owners":[12],"pid":{"revision_id":0,"type":"depid","value":"8205"},"status":"published"},"_oai":{"id":"oai:ouj.repo.nii.ac.jp:00008205","sets":["389:528"]},"author_link":["10444","10440","10441","10445","10443","10442"],"item_10001_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2004-10-25","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"5","bibliographicPageEnd":"616","bibliographicPageStart":"600","bibliographicVolumeNumber":"113","bibliographic_titles":[{"bibliographic_title":"地學雜誌"},{"bibliographic_title":"Journal of Geography (Chigaku Zasshi)","bibliographic_titleLang":"en"}]}]},"item_10001_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Recent advances in seismic studies have revealed that earthquakes have a close link with chemical processes, <I>i.e.</I> metamorphic dehydration. From this point of view, we provide a new scheme for observation of on-going regional metamorphism in a subduction zone.<BR>Combining the phase diagrams of MORB + water and peridotite + water with the thermal structure of the descending Pacific oceanic plate in NE Japan and in the Philippine Sea (PHS) plate in SW Japan, we can draw the distribution of metamorphic facies of regional metamorphism. However, the most uncertain parameter is thermal structure, even though it has been calculated numerically, because of the difficulty of evaluating frictional heating, heat transportation by dehydrated fluids and mantle convection in the hanging wall. To overcome this problem, we have carried out different approach from seismic observations in estimating the thermal structure of a subduction zone, by applying the dehydration-induced earthquake hypothesis. This hypothesis involves the assumptions as follows : 1) any dehydration in the subducted slab induces earthquakes, 2) peridotite of the subducting plate is more or less hydrated, as well as the oceanic crust, and 3) the dehydration reactions proceed in near equilibrium condition.<BR>Direct seismic determination of the depths of the blueschist or epidote-amphibolite facies to eclogite transformation, decomposition of serpentine (antigorite), and the stability limit of clinochlore enable us to establish fixed points for the slab temperature. The seismogenic zone (150°C to 350°C), the depth limit of non-volcanic tremor seismicity, and the slab melting in SW Japan (800-900°C) were also used to fix temperatures at given depths. Three profiles in NE-Japan and two profiles in SW-Japan were examined, and their P-T paths along the Wadati-Benioff zone were estimated to be anti-clockwise in all cases. The P-T paths are consistent with those of metamorphic facies series from well-studied on-land regional metamorphic belts. The P-T path of the subducting slab in NE-Japan is colder than that of the eastern-Shikoku section in SW-Japan, except for the Kii-peninsula section which has an almost similar P-T path to that in NE-Japan.<BR>Comparison between the on-going metamorphism beneath the Japanese islands and the on-land regional metamorphic belts in the Sanbagawa and Kokchetav shows that the P-T conditions of these two metamorphic belts are located between that of NE-Japan and of the eastern-Shikoku profile.<BR>A numerical model for wedge-mantle convection shows that the direction of the small corner flow of the wedge mantle causes a back current along the subducting slab. The area of the corner flow is wider in a shallow subduction zone corresponding to that in eastern Shikoku, and is narrower in a steeper subduction zone represented by NE-Japan. Since the exhumed metamorphic belts have intermediate P-T conditions between those in NE Japan and eastern Shikoku, We suggest that a change in the mode of wedge-corner flow from steep to shallow subduction plays some role in the exhumation of a metamorphic belt. Such a change in Cretaceous time from 120 Ma to 80 Ma may have promoted the exhumation of the Sanbagawa belt.","subitem_description_type":"Abstract"}]},"item_10001_description_6":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"Recent advances in seismic studies have revealed that earthquakes have a close link with chemical processes, <I>i.e.</I> metamorphic dehydration. From this point of view, we provide a new scheme for observation of on-going regional metamorphism in a subduction zone.<BR>Combining the phase diagrams of MORB + water and peridotite + water with the thermal structure of the descending Pacific oceanic plate in NE Japan and in the Philippine Sea (PHS) plate in SW Japan, we can draw the distribution of metamorphic facies of regional metamorphism. However, the most uncertain parameter is thermal structure, even though it has been calculated numerically, because of the difficulty of evaluating frictional heating, heat transportation by dehydrated fluids and mantle convection in the hanging wall. To overcome this problem, we have carried out different approach from seismic observations in estimating the thermal structure of a subduction zone, by applying the dehydration-induced earthquake hypothesis. This hypothesis involves the assumptions as follows : 1) any dehydration in the subducted slab induces earthquakes, 2) peridotite of the subducting plate is more or less hydrated, as well as the oceanic crust, and 3) the dehydration reactions proceed in near equilibrium condition.<BR>Direct seismic determination of the depths of the blueschist or epidote-amphibolite facies to eclogite transformation, decomposition of serpentine (antigorite), and the stability limit of clinochlore enable us to establish fixed points for the slab temperature. The seismogenic zone (150°C to 350°C), the depth limit of non-volcanic tremor seismicity, and the slab melting in SW Japan (800-900°C) were also used to fix temperatures at given depths. Three profiles in NE-Japan and two profiles in SW-Japan were examined, and their P-T paths along the Wadati-Benioff zone were estimated to be anti-clockwise in all cases. The P-T paths are consistent with those of metamorphic facies series from well-studied on-land regional metamorphic belts. The P-T path of the subducting slab in NE-Japan is colder than that of the eastern-Shikoku section in SW-Japan, except for the Kii-peninsula section which has an almost similar P-T path to that in NE-Japan.<BR>Comparison between the on-going metamorphism beneath the Japanese islands and the on-land regional metamorphic belts in the Sanbagawa and Kokchetav shows that the P-T conditions of these two metamorphic belts are located between that of NE-Japan and of the eastern-Shikoku profile.<BR>A numerical model for wedge-mantle convection shows that the direction of the small corner flow of the wedge mantle causes a back current along the subducting slab. The area of the corner flow is wider in a shallow subduction zone corresponding to that in eastern Shikoku, and is narrower in a steeper subduction zone represented by NE-Japan. Since the exhumed metamorphic belts have intermediate P-T conditions between those in NE Japan and eastern Shikoku, We suggest that a change in the mode of wedge-corner flow from steep to shallow subduction plays some role in the exhumation of a metamorphic belt. Such a change in Cretaceous time from 120 Ma to 80 Ma may have promoted the exhumation of the Sanbagawa belt.","subitem_description_type":"Other"}]},"item_10001_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"10443","nameIdentifierScheme":"WEKO"}],"names":[{"name":"MARUYAMA, Shigenori"}]},{"nameIdentifiers":[{"nameIdentifier":"10444","nameIdentifierScheme":"WEKO"}],"names":[{"name":"OMORI, Soichi"}]},{"nameIdentifiers":[{"nameIdentifier":"10445","nameIdentifierScheme":"WEKO"}],"names":[{"name":"IWASE, Yasuyuki"}]}]},"item_10001_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"公益社団法人 東京地学協会"}]},"item_10001_source_id_11":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN00322536","subitem_source_identifier_type":"NCID"}]},"item_10001_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0022135X","subitem_source_identifier_type":"ISSN"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"丸山, 茂徳"}],"nameIdentifiers":[{"nameIdentifier":"10440","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"大森, 聡一"}],"nameIdentifiers":[{"nameIdentifier":"10441","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"岩瀬, 康行"}],"nameIdentifiers":[{"nameIdentifier":"10442","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2014-09-05"}],"displaytype":"detail","filename":"113_600.pdf","filesize":[{"value":"2.6 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"日本列島直下で現在進行中の広域変成作用","url":"https://ouj.repo.nii.ac.jp/record/8205/files/113_600.pdf"},"version_id":"663227fd-091f-4658-aeb7-3403f9c80438"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"沈み込み帯","subitem_subject_scheme":"Other"},{"subitem_subject":"スラブ内地震","subitem_subject_scheme":"Other"},{"subitem_subject":"広域変成作用","subitem_subject_scheme":"Other"},{"subitem_subject":"脱水誘発地震仮説","subitem_subject_scheme":"Other"},{"subitem_subject":"東北日本","subitem_subject_scheme":"Other"},{"subitem_subject":"西南日本","subitem_subject_scheme":"Other"},{"subitem_subject":"変成岩の上昇","subitem_subject_scheme":"Other"},{"subitem_subject":"subduction_zone","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"intraslab_eathquake","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"regional_metamorphism","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"dehydraion-induced_earthquake_hypothesis","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"northeastern_Japan","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"southwestern_Japan","subitem_subject_language":"en","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"journal article","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"日本列島直下で現在進行中の広域変成作用","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"日本列島直下で現在進行中の広域変成作用"},{"subitem_title":"On-going Regional Metamorphism beneath the Japanese Islands","subitem_title_language":"en"}]},"item_type_id":"10001","owner":"12","path":["528"],"pubdate":{"attribute_name":"公開日","attribute_value":"2014-09-05"},"publish_date":"2014-09-05","publish_status":"0","recid":"8205","relation_version_is_last":true,"title":["日本列島直下で現在進行中の広域変成作用"],"weko_creator_id":"12","weko_shared_id":-1},"updated":"2023-06-20T16:12:15.549878+00:00"}