Journal of the Geological Society of Japan最新文献

K-Ar ages of an andesitic parallel dike swarm in the Takane area, Takayama City, Gifu Prefecture, Central Japan 日本中部岐阜县高山市高根地区安山岩平行脉群的K-Ar年龄

Journal of the Geological Society of Japan Pub Date : 2020-09-15 DOI: 10.5575/geosoc.2020.0021

M. Niwa, Tadamasa Ueki, H. Hoshi, Y. Sugisaki, K. Yagi, Terumasa Tozawa

引用次数: 0

Erratum : Granites of Japan: 勘误:日本花岗岩:

Journal of the Geological Society of Japan Pub Date : 2020-08-15 DOI: 10.5575/geosoc.erratum_2020.08

T. Nakajima

引用次数: 0

The discovery of ikaite from sediment cores in the eastern margin of the Japan Sea and its significance 日本海东缘沉积物岩心中衣海岩的发现及其意义

Journal of the Geological Society of Japan Pub Date : 2019-12-15 DOI: 10.5575/geosoc.2019.0034

Y. Kakuwa, Naizhong Zhang, R. Matsumoto, H. Tomaru, N. Ishida, Tatsuya Motegi

{"title":"The discovery of ikaite from sediment cores in the eastern margin of the Japan Sea and its significance","authors":"Y. Kakuwa, Naizhong Zhang, R. Matsumoto, H. Tomaru, N. Ishida, Tatsuya Motegi","doi":"10.5575/geosoc.2019.0034","DOIUrl":"https://doi.org/10.5575/geosoc.2019.0034","url":null,"abstract":"The low-temperature carbonate mineral ikaite was recovered from sediment cores from the Sado West area, in the eastern margin of the Japan Sea. The ikaite-bearing sediments consist of dark-colored, bioturbated or burrow-mottled mud with sand and silt laminae. There are rare occurrences of ikaite within mud containing thin, parallel laminations indicative of anoxic sedimentary environments. Ikaite occurs either as veins of granular aggregates or as large crystals, some of which exceed 10 cm in length. The nature of the ikaite occurrences indicate that it is unlikely that ikaite formed directly on the seafloor. The ikaite deposits are found at depths shallower than 10 meters below the sea floor (mbsf), but pore-water analysis suggests that the ikaite crystals formed within the sulfate–methane transition (SMT) zone, likely at 2–5 mbsf. The ikaite stable carbon isotopic ratios are low, -33 to -34 per mil, indicating that carbon derived from microbial oxidation of methane gas was involved in ikaite formation, consistent with the occurrence of ikaite within the SMT. The most recent formation of ikaite is calculated to be more than 9,700 years ago. All ikaite occurrences are in cores that do not contain methane hydrates. Hydrate-bearing cores are usually associated with calcite nodules. Further investigation is required to determine the controlling factors in the formation of either ikaite or ordinary calcite. Ikaite becomes unstable at depths greater than 70 mbsf as the methane flux or the temperature increases during burial. Large crystals of ikaite are replaced by stable calcite to form Gennou Ishi.","PeriodicalId":264556,"journal":{"name":"Journal of the Geological Society of Japan","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125786192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Geology of the Maizuru and Obama districts, Southwest Japan: 日本西南部迈祖和奥巴马地区的地质

Journal of the Geological Society of Japan Pub Date : 2019-11-15 DOI: 10.5575/geosoc.2019.0030

M. Kametaka, Yoshiaki Sugamori, N. Ishida, Kazuo Matsui, H. Kishimoto, T. Umeda, Atsuyoshi Higashi, H. Yamane, T. Sugimori, S. Uozumi, T. Nagata, K. Matsuba, Yasue Kuwajima, A. Iwamori, K. Kanaya

引用次数: 1

Geology of the Nishinoomote Formation, Kumage Group, in the northern part of Tanegashima Island, Kagoshima Prefecture, SW Japan 日本西南部鹿儿岛县种子岛北部Kumage群Nishinoomote组地质

Journal of the Geological Society of Japan Pub Date : 2018-05-15 DOI: 10.5575/GEOSOC.2017.0082

Akihide Kikukawa, Y. Aita, K. Kameo, N. Kotake

{"title":"Geology of the Nishinoomote Formation, Kumage Group, in the northern part of Tanegashima Island, Kagoshima Prefecture, SW Japan","authors":"Akihide Kikukawa, Y. Aita, K. Kameo, N. Kotake","doi":"10.5575/GEOSOC.2017.0082","DOIUrl":"https://doi.org/10.5575/GEOSOC.2017.0082","url":null,"abstract":"Geology, geological age, and sedimentary environment of the Nishinoomote Formation in the Kumage Group distributed in Tanegashima Island, Kagoshima, Japan were examined on the basis of detailed mapping of lithology, biostratigraphic data of radiolarian fossils and calcareous nannofossils, and ichnological analysis. Since the Nishinoomote Formation consists mainly of sandy sediments, mudstone containing large amounts of trace fossils in the middle stratigraphic interval of the Nishinoomote is newly subdivided as the Okubo Mudstone Member. The Nishinoomote Formation correlated with the radiolarian fossil zone RP20c–RP21a (31.1–28.5 Ma) and the calcareous nannofossil zone NP23–NP24 (30.00–26.84 Ma). Therefore, geological age of the Nishinoomote Formation can be considered to be late early Oligocene (30.0–28.5 Ma). Investigation of the distribution pattern of lithology and the geological age revealed that (1) contemporaneous stratigraphic intervals in the Nishinoomote Formation repeatedly appeared due to folds and thrusts, (2) total thickness of the Nishinoomote seems to be less than 1000 m, which is thinner than those estimated by previous authors, (3) the Nishinoomote can be correlated with not the Hyuga but the Nichinan Groups distributed in Kyusyu, and (4) depositional environment for the Nishinoomote might be a sea-floor deeper than 2000 m in water depth. Further detailed sedimentological approach must be required to clarify the origin of the Nishinoomote Formation.","PeriodicalId":264556,"journal":{"name":"Journal of the Geological Society of Japan","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123185140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Reexamination on stratigraphy of the Middle to Upper Pleistocene Shimosa Group beneath the Tsukuba Upland, Ibaraki Prefecture, central Japan 日本中部茨城县筑波高地中至上更新世下佐群地层学的再考察

Journal of the Geological Society of Japan Pub Date : 2018-05-15 DOI: 10.5575/GEOSOC.2017.0076

K. Sakata, T. Naya, Misao Hongo, H. Nakazato, T. Nakazawa

{"title":"Reexamination on stratigraphy of the Middle to Upper Pleistocene Shimosa Group beneath the Tsukuba Upland, Ibaraki Prefecture, central Japan","authors":"K. Sakata, T. Naya, Misao Hongo, H. Nakazato, T. Nakazawa","doi":"10.5575/GEOSOC.2017.0076","DOIUrl":"https://doi.org/10.5575/GEOSOC.2017.0076","url":null,"abstract":"The stratigraphy of the Middle to Upper Pleistocene Shimosa Group beneath the Tsukuba Upland area of Ibaraki Prefecture, Kanto Plain, central Japan has been reexamined by performing detailed facies observations and analyzing intercalated tephra layers and fossil pollen assemblages in sediment cores. The Pleistocene deposits in the sediment cores are divided into five depositional cycles, each composed of fluvial and coastal sediments that formed under the influence of glacioeustacy. These cycles are correlated with the Yabu, Kamiizumi, Kiyokawa (Kamiiwahashi), Kioroshi, and Joso formations in ascending order based on the tephroand palyno-stratigraphy. Of note, the incised valley fill beneath the Tsukuba Upland area, which was previously correlated with the Kamiiwahashi Formation (MIS 7), corresponds to the Kioroshi Formation (MIS 5e). The valley was incised during MIS 6, which was one of the most prominent sea level lowstands of the last 400 ky. The new correlation is consistent with the distribution of equivalent incised valley fills in the Kioroshi Formation beneath the Kanto Plain in Chiba and Saitama prefectures.","PeriodicalId":264556,"journal":{"name":"Journal of the Geological Society of Japan","volume":"170 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123194931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Stratigraphy and distribution pattern of volcanogenic sediments beneath downtown Mashiki, Kumamoto, SW Japan, seriously damaged by the 2016 Kumamoto Earthquake 2016年熊本地震严重破坏的熊本益城市区火山沉积层地层学及分布格局

Journal of the Geological Society of Japan Pub Date : 2018-05-15 DOI: 10.5575/GEOSOC.2017.0077

T. Nakazawa, K. Sakata, Yoshiki Sato, H. Hoshizumi, A. Urabe, M. Yoshimi

引用次数: 1

Faults affecting the basement and surface soil in the aftershock area of the 1997 Northwestern Kagoshima Earthquake 1997年鹿儿岛西北部地震余震区影响基底和表层土壤的断层

Journal of the Geological Society of Japan Pub Date : 2018-05-15 DOI: 10.5575/GEOSOC.2018.0006

H. Mukoyoshi, H. Hayashi, H. Uchida, Natsu Yoshizaki, T. Takeda, K. Goto, S. Sekine, K. Kasahara

{"title":"Faults affecting the basement and surface soil in the aftershock area of the 1997 Northwestern Kagoshima Earthquake","authors":"H. Mukoyoshi, H. Hayashi, H. Uchida, Natsu Yoshizaki, T. Takeda, K. Goto, S. Sekine, K. Kasahara","doi":"10.5575/GEOSOC.2018.0006","DOIUrl":"https://doi.org/10.5575/GEOSOC.2018.0006","url":null,"abstract":": In 1997 , two strong earthquakes occurred on March 26 (M j 6 . 6 ) and May 13 (M j 6 . 4 ) in the northwestern part of Kagoshima Prefecture, Japan (termed the 1997 Northwestern Kagoshima Earthquakes). However no seismogenic faults associated with these earthquakes had previously been recognized at the surface. In this study, we report structural observations from newly recognized fault outcrops located 1 . 5 and 2 km southwest of the epicenter of the M j 6 . 6 earthquake. One outcrop consists of the Miocene Shibi-san Granodiorite, which is unconformably overlain by lower sandy loam, lower humic soil, upper sandy loam, and upper humic soil layers that are clearly offset by steeply dipping faults. We measured ~ 40 cm of vertical separa-tion of the contact between the lower sandy loam and lower humic soil layers along a WNW-trending fault, above which the ground surface flexed upward by about 20 cm. The second outcrop is a streambed expo-sure of the Shibi-san Granodiorite that shows a 30 -cm-thick layer of foliated cataclasite along a fault plane, with textural evidence of sinistral slip.","PeriodicalId":264556,"journal":{"name":"Journal of the Geological Society of Japan","volume":" 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134218137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Lecture note on the theories of strain and deformation analyses:: 7. Inverse method for determining non-coaxial, finite deformations 应变与变形分析理论课堂讲稿:确定非同轴有限变形的逆方法

Journal of the Geological Society of Japan Pub Date : 2018-05-15 DOI: 10.5575/GEOSOC.2017.0083

A. Yamaji

引用次数: 0

Eruptive history of Asahidake Volcano, central Hokkaido: New study of the stratigraphy and eruption ages of the Asahidake late stage products. 北海道中部旭日山火山喷发史:旭日山晚期产物地层与喷发时代的新研究。

Journal of the Geological Society of Japan Pub Date : 2018-04-15 DOI: 10.5575/GEOSOC.2018.0001

Kosuke Ishige, M. Nakagawa, Y. Ishizuka

{"title":"Eruptive history of Asahidake Volcano, central Hokkaido: New study of the stratigraphy and eruption ages of the Asahidake late stage products.","authors":"Kosuke Ishige, M. Nakagawa, Y. Ishizuka","doi":"10.5575/GEOSOC.2018.0001","DOIUrl":"https://doi.org/10.5575/GEOSOC.2018.0001","url":null,"abstract":"The eruptive history and eruption style of Asahidake volcano, the youngest volcanic edifice of the Taisetsu Volcano Group, central Hokkaido, Japan, are investigated to evaluate its long-term volcanic hazards. The Asahidake edifice consists of a pyroclastic cone whose growth is associated with lava effusions since the late Pleistocene. The eruption rate was relatively high, with an estimated 1.0 km dense rock equivalent (DRE)/ky from 15 ka to 9 ka that rapidly decreased to 0.03 km DRE/ky from 9 ka to present. After the latest magmatic eruption ca. 5 ka, there was a 2 ky dormant period that was followed by a large-scale phreatic eruption ca. 2.8 ka, which possessed the following eruption sequence. The sequence began with edifice collapse that produced a debris avalanche and formed the Jigokudani horseshoe-shaped crater, followed by phreatic explosions. Lahar flows then effused from many small craters and fissures that had formed in and at the opening part of the Jigokudani crater. This eruptive activity decreased after the eruption sequence. We recognize that the most recent small-scale phreatic eruption occurred ca. 0.7 ka. Although the current fumarole activity is remarkable, it appears that the eruptive activity has declined considerably since the 2.8 ka eruption. Considering the temporal change in eruptive activity, it is possible that the activity of Asahidake volcano has monotonically decreased over the past 10,000 years. However, in the context of volcanic hazard mitigation, it should be noted that small-scale phreatic explosions and/or effusions of lahar similar to the 0.7 ka eruption might potentially occur and endanger tourism activities.","PeriodicalId":264556,"journal":{"name":"Journal of the Geological Society of Japan","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125999185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0