Journal: Geochemical Journal

Abbreviation

Geochem. J.

Publisher

Geochemical Society of Japan

Journal Volumes

ISSN

1880-5973
0016-7002

Description

Filters

2012 - 201952020 - 20252
Reset filters

Search Results

Publications 1 - 7 of 7
  • Preface
    Item type: Journal Article
    Tachibana, S.; Busemann, H.; Bonal, L. (2014)
    Geochemical Journal
  • Springwater chemical anomalies prior to the Mw = 7.2 Van Earthquake (Turkey)
    Item type: Journal Article
    Inan, Sedat; Balderer, Werner P.; Leuenberger-West, Fanny; et al. (2012)
    Geochemical Journal
  • The molybdenum isotopic composition of the modern ocean
    Item type: Journal Article
    Nakagawa, Yusuke; Takano, Shotaro; Firdaus, M. Lutfi; et al. (2012)
    Geochemical Journal
  • Radiocarbon content of carbon dioxide and methane in hydrothermal fluids of Okinawa Trough vents
    Item type: Journal Article
    Kawagucci, Shinsuke; Matsui, Yohei; Früh-Green, Gretchen L. (2020)
    Geochemical Journal
    Here we quantify radiocarbon (14C) content in CO2 and CH4 from hydrothermal fluids collected at 5 vent sites in the Okinawa Trough. These data provide preliminary insights on how different carbon sources and circulation processes contribute to vent fluids and take into consideration all potential contaminations during sample processing and analysis with accelerator mass spectrometer. For CO214C-dead values observed in fluids of most sites (Hatoma, Hitoshi, Noho) demonstrate the complete removal of the inorganic carbon in the recharged seawater. Conversely, the significantly positive 14CO2 are detected in fluids from the Daiyon-Yonaguni site, which implies the persistence of the recharged seawater-derived inorganic carbon and/or a contribution from thermal degradation of sedimentary 14C-containing carbon during fluid upwelling. The CH4 in these fluids were predominantly 14C-dead or nearly 14C-dead, suggesting a source of deep-buried, 14C-dead sedimentary carbon. The methods outlined in our study exemplify a useful way of elucidating radiocarbon contents of geofluids, and provide future studies with a means to improve our understanding of carbon circulation between hydrosphere and lithosphere. © 2020 by The Geochemical Society of Japan.
  • Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis
    Item type: Journal Article
    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; et al. (2015)
    Geochemical Journal
  • Major elements and noble gases of the Jinju (H5) meteorite, an observed fall on March 9, 2014, in South Korea
    Item type: Journal Article
    Nagao, Keisuke; Haba, Makiko K.; Lee, Jong I.; et al. (2016)
    Geochemical Journal
  • The elemental abundances of Ryugu: Assessment of chemical heterogeneities and the nugget effect
    Item type: Journal Article
    Yokoyama, Tetsuya; Dauphas, Nicolas; Fukai, Ryota; et al. (2025)
    Geochemical Journal
    The Hayabusa2 spacecraft sampled ~5.4 g of asteroid material from the Cb-type asteroid Ryugu. Initial analysis of the Ryugu materials revealed a mineralogical, chemical, and isotopic kinship to the CI chondrites. In this study, we have summarized the elemental abundances of Ryugu samples published to date, and evaluated their compositional variability associated with the CI chondrite data. The abundances of some elements (e.g., P, Ca, Mn, and rare earth elements) in individual Ryugu particles were found to show large relative dispersions compared to the other elements, presumably due to the nugget effect of aqueously formed minor secondary minerals (e.g., dolomite, apatite, magnetite, and pyrrhotite). Consequently, the mean abundances of Ryugu for these elements, calculated using currently available Ryugu data, are accompanied by a certain degree of uncertainties. We suggest establishing a consortium to determine the representative elemental abundances of Ryugu by measuring aliquots from a large homogenized powder sample that can mitigate the nugget effect. Our statistical calculation shows that at least 750 and 400 mg of homogenized samples from Chambers A and C, respectively, are needed to achieve within $\pm$ 5% compositional heterogeneity. The data obtained throughout the consortium activity complement the scientific objectives of the Hayabusa2 mission. Moreover, we anticipate that the obtained Ryugu data, coupled with the elemental abundances of CI chondrites, provide new insights into the chemical composition of the Solar System, which will be used by multidisciplinary communities, including Earth and planetary sciences, astronomy, physics, and chemistry.
Publications 1 - 7 of 7