A5100759109- Geological and Geochemical Analysis
- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Methane Hydrates and Related Phenomena
- earthquake and tectonic studies
- Geochemistry and Geologic Mapping
- High-pressure geophysics and materials
- Isotope Analysis in Ecology
- Radioactive element chemistry and processing
- Geological and Geophysical Studies
- Hydrocarbon exploration and reservoir analysis
- Geological Studies and Exploration
- Radioactive contamination and transfer
- Astro and Planetary Science
- Heavy metals in environment
- Microbial Community Ecology and Physiology
- Groundwater and Isotope Geochemistry
- Nuclear Physics and Applications
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Metal Extraction and Bioleaching
- Reservoir Engineering and Simulation Methods
- Analytical chemistry methods development
- CO2 Sequestration and Geologic Interactions
Japan Agency for Marine-Earth Science and Technology
2016-2025
Fukushima University
2025
The University of Tokyo
1983-2020
Naval Submarine Medical Research Laboratory
2014-2019
Kyoto University
2000-2018
Hamamatsu Photonics (Japan)
2008-2018
Naval Hospital Yokosuka Japan
2014-2018
Yamagata Prefectural University of Health Sciences
2010-2017
Tohoku University
2010-2016
Chiba University
2008-2016
Research Article| September 01, 2009 Ontong Java Plateau eruption as a trigger for the early Aptian oceanic anoxic event Maria Luisa G. Tejada; Tejada 1National Institute of Geological Sciences (NIGS), University Philippines, Quezon City, 1101, Philippines2Institute on Earth Evolution (IFREE), Japan Agency Marine-Earth Science and Technology, Yokosuka, 237-0061, Search other works by this author on: GSW Google Scholar Katsuhiko Suzuki; Suzuki 2Institute Junichiro Kuroda; Kuroda Rodolfo...
Abstract It has been suggested that Saturn’s moon Enceladus possesses a subsurface ocean. The recent discovery of silica nanoparticles derived from shows the presence ongoing hydrothermal reactions in interior. Here, we report results detailed laboratory experiments to constrain reaction conditions. To sustain formation nanoparticles, composition Enceladus’ core needs be similar carbonaceous chondrites. We show would consistent with NH 3 - and CO 2 -rich plume compositions. suggest high...
Research Article| January 01, 2013 Petrological and Nd-Sr-Os isotopic constraints on the origin of high-Mg adakitic rocks from North China Craton: Tectonic implications Bin Chen; Chen 1Key Laboratory Orogenic Belts Crustal Evolution, Peking University, Beijing 100871, Search for other works by this author on: GSW Google Scholar Bor-Ming Jahn; Jahn 2Department Geosciences, National Taiwan P.O. Box 13-318, Taipei, Katsuhiko Suzuki 3Institute Earth JAMSTEC, Yokosuka 237-0061, Japan Author...
Combined Pb-Sr-Nd-Hf-Os isotopes, together with major and trace element compositions, were determined from clinopyroxene olivine phenocrysts, along whole rocks, for ocean island basalts high μ (μ = 238U/204Pb) (HIMU) enriched mantle isotopic characteristics Cook-Austral Islands. Clinopyroxene separates record reliable information of the sources because minimized in situ radiogenic ingrowth their lower susceptibility to crustal contamination. Coherent systematics multi-isotope spaces defined...
Metalliferous umbers and red shales occur as unique products of the Kula‐Pacific ridge‐forearc collision in Late Cretaceous Shimanto Supergroup, an accretionary complex Japan. These are closely associated with greenstones mid‐ocean ridge basalt (MORB) origin regarded hydrothermal metalliferous precipitates related to MOR‐type volcanism. The were deposited trench area where both terrigenous detritus from land particulates a MOR supplied simultaneously. Besides predominance Fe Mn, exhibit...
Research Article| December 01, 2010 Marine osmium isotope record across the Triassic-Jurassic boundary from a Pacific pelagic site Junichiro Kuroda; Kuroda * 1Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan2National Oceanography Centre, Southampton, University of Southampton SO14 3ZH, UK *E-mail: kurodaj@jamstec.go.jp. Search other works by this author on: GSW Google Scholar Rie S. Hori; Hori 3Graduate School Engineering, Ehime University, Matsuyama 790-8577,...
[1] Molecular hydrogen, H2, is the key component to link inorganic lithosphere with subsurface biosphere. Geochemical and microbiological characterizations of natural hydrothermal fields strongly suggested that H2 an important energy source in microbial ecosystems because its metabolic versatility. One possible sources has been considered as earthquakes: mechanoradical reactions on fault surfaces generate during earthquake faulting. However it unclear whether faulting can abundant sustain...
We have discovered deep-sea mud that is extremely enriched in rare-earth elements and yttrium (together called REY) the Japanese Exclusive Economic Zone around Minamitorishima Island, western North Pacific Ocean. The maximum total REY concentration reaches approximately 7000 ppm, which much higher than reported for conventional deposits on land other known potential resources ocean. REY-rich characterized by abundant phillipsite biogenic calcium phosphate. In addition, stratigraphic layer...
Radioactive strontium-90 scattered by a nuclear power plant accident was specifically quantified conventional inductively coupled plasma quadrupole mass-spectrometry (ICP-QMS) preceded on-line chelate column separation (based on lab-on-valve) and oxygen reaction (designated the cascade step). The proposed system overcomes isobaric interference of 90Zr, whose soil concentration exceeds that 90Sr more than six orders magnitude. In addition, requires no ultimate mass spectrometry or radioactive...
Abstract Deep‐sea hydrothermal vents discharge abundant reductive energy into oxidative seawater. Herein, we demonstrated that in situ measurements of redox potentials on the surfaces active mineral deposits were more negative than surrounding seawater potential, driving electrical current generation. We also surface minerals widespread fields, regardless proximity to fluid discharges. Lab experiments verified potential was induced by a distant electron transfer from through metallic and...
Abstract The Cretaceous Period was marked by the formation of numerous large igneous provinces (LIPs), several which were associated with geologically rapid climate, environmental and biosphere perturbations, including early Aptian latest Cenomanian oceanic anoxic events (OAEs 1a 2, respectively). In most cases, magmatic CO 2 emissions are thought to have been major driver climate degradation. This work summarizes relationships between LIPs focusing on how volcanism caused warming during OAE...
Abstract The volcanic episode that formed Ontong Java Nui (OJN) in the western Pacific ~ 120 million-year-ago is thought to have triggered Oceanic Anoxic Event (OAE) 1a, yet cause-effect relationship remains insufficiently understood. Here, we present a Pb-Os-C isotope dataset for tracking OJN volcanism across sedimentary sequence containing OAE1a record central Pacific. Lead isotopic evidence strongly supports deposition of OJN-sourced ash layers at this site after paired seawater δ 13 C...
Since their discovery in the late 1970s, deep-sea hydrothermal systems have been considered as likely candidates for origin and early evolution of life on Earth. However, while subsequent investigations revealed a great diversity modern ecosystems, they done little to shed light issues life, metabolism, cells, or communities. Phylogenetic, biochemical geochemical clues all seem point hydrogenotrophic chemolithoautotrophy such methanogenesis sulfurreduction, thus pinpointing availability...
A stereoselective and efficient total synthesis of optically active tetrodotoxin (TTX) is described. polyfunctionalized key cyclitol compound containing branched-chains for the TTX was prepared from d-glucose employing Henry reaction (Nitro aldol reaction) as transformation. Stereoselective construction α-azido-aldehyde branched-chain achieved via spiro α-chloroepoxide intermediate.