A5011111581- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Geological and Geochemical Analysis
- Isotope Analysis in Ecology
- earthquake and tectonic studies
- Paleontology and Stratigraphy of Fossils
- Methane Hydrates and Related Phenomena
- Groundwater and Isotope Geochemistry
- Astro and Planetary Science
- Geochemistry and Geologic Mapping
- Hydrocarbon exploration and reservoir analysis
- Marine and coastal ecosystems
- Radioactive element chemistry and processing
- Mass Spectrometry Techniques and Applications
- Geological formations and processes
- Heavy metals in environment
- Geological and Geophysical Studies
- Coral and Marine Ecosystems Studies
- Atmospheric and Environmental Gas Dynamics
- Identification and Quantification in Food
- Microbial Community Ecology and Physiology
- Marine and fisheries research
- Marine and environmental studies
- Cultural Heritage Materials Analysis
- Chemical Synthesis and Characterization
National Institute of Advanced Industrial Science and Technology
2015-2024
Geological Survey of Japan
2015-2024
Kyushu University
2024
Government of British Columbia
2022
Japan Advanced Institute of Science and Technology
2021
Japan Research Institute
2016
Sphere Institute
2014
The University of Tokyo
2010-2013
Samples from the carbonaceous asteroid (162173) Ryugu provide information on chemical evolution of organic molecules in early solar system. Here we show element partitioning major component ions by sequential extractions salts, carbonates, and phyllosilicate-bearing fractions to reveal primordial brine composition primitive asteroid. Sodium is dominant electrolyte salt fraction extract. Anions NH4+ are more abundant than carbonate phyllosilicate fractions, with molar concentrations order...
Polycyclic aromatic hydrocarbons (PAHs) contain ≲20% of the carbon in interstellar medium. They are potentially produced circumstellar environments (at temperatures ≳1000 kelvin), by reactions within cold (~10 kelvin) clouds, or processing carbon-rich dust grains. We report isotopic properties PAHs extracted from samples asteroid Ryugu and meteorite Murchison. The doubly-13C substituted compositions (Δ2×13C values) naphthalene, fluoranthene, pyrene 9 to 51‰ higher than values expected for a...
Research Article| August 01, 2013 Tsunami recurrence revealed by Porites coral boulders in the southern Ryukyu Islands, Japan Daisuke Araoka; Araoka * 1Graduate School of Frontier Sciences, The University Tokyo, Kashiwa 277-8561, Japan2Atmosphere and Ocean Institute, 277-8564, *E-mail: araoka@aori.u-tokyo.ac.jp. Search for other works this author on: GSW Google Scholar Yusuke Yokoyama; Yokoyama 2Atmosphere Japan3Department Earth Planetary Science, Tokyo 113-0033, Japan4Institute...
Abstract We report primordial aqueous alteration signatures in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu by Hayabusa2 spacecraft of JAXA. Newly identified low-molecular-weight hydroxy acids (HO-R-COOH) and dicarboxylic (HOOC-R-COOH), such as glycolic acid, lactic glyceric oxalic succinic are predominant samples two touchdown locations at Ryugu. The quantitative qualitative profiles for hydrophilic between sampling shows similar trends within order ppb...
Zinc stable isotopes (δ66Zn) serve as a widely fingerprinting tool for detecting anthropogenic Zn contamination. However, there is limited understanding of δ66Zn behavior during the sorption to minerals and organic matter. In this study, we have determined values in specific fractions investigate their effectiveness tracing Zn. The revised Community Bureau Reference (BCR) extraction procedure was applied coastal marine core from Osaka Bay lacustrine Lake Biwa, both with history metal...
The chronicles of the Ryukyu Kingdom describe at least four coastal inundation events Ishigaki Island during seventeenth through nineteenth centuries: 1771 Meiwa earthquake tsunami, which killed 12,000 people; another tsunami (1687); and two with unrecorded causes (1625 1714). We used a high‐resolution U/Th method to date well‐preserved surface parts massive Porites spp. coral head boulders that had been cast ashore found ages correspond event. One large boulder (diameter > 4 m) was dated...
Abstract The Li isotope ratio (δ 7 Li) is expected to be a useful tracer of silicate weathering in river and groundwater systems, which an important contributor the seawater compositional changes that accompany evolution Earth's surface environment. To obtain accurate estimates continental fluxes ocean, we determined δ values dissolved lower Ganges‐Brahmaputra system both dry rainy seasons, deep Bengal basin. Dissolved reaches rivers (0.04–0.66 µmol kg −1 +19.1‰ +34.2‰, respectively) were...
Abstract The Li concentration and isotopic composition (δ 7 Li) in submarine vent fluids are important for oceanic budget potentially useful investigating hydrothermal systems deep under the seafloor because highly enriched relative to seawater. Although geochemistry has been studied at mid‐ocean‐ridge (MOR) sites, arc back‐arc settings not systematically investigated. Here we determined δ 87 Sr/ 86 Sr values of 11 end‐member from 5 western Pacific examined behavior during high‐temperature...
For the rapid, easy, and safe purification of alkali alkaline-earth elements from rock samples for stable isotope analysis, we developed a semi-automated, high-throughput procedure using borate fusion an ion chromatography system equipped with fraction collector. This HF-free decomposition silicate can be performed in short time without fractionation; enables collection baseline-separated peaks multiple target complete removal interference matrices reagents samples. The accuracy this was...
Abstract Detailed reconstruction of Indian summer monsoons is necessary to better understand the late Quaternary climate history Bay Bengal and peninsula. We established a chronostratigraphy for sediment core from Hole 19B in western Bengal, extending approximately 80 kyr BP examined major trace element compositions clay mineral components sediments. Higher δ 18 O values, lower TiO 2 contents, weaker weathering source area during marine isotope stages (MIS) 4 compared MIS 1, 3, 5 are...
Understanding future changes in the concentrations of elements such as Cd mine drainages, which can cause severe environmental impacts, is crucial to strategically optimize treatment and management drainages. In this study, on basis 17-year data (2003–2019) for 99 untreated drainages from legacy mines Japan, we developed a Bayesian hierarchical log-linear model that capture temporal seven including six metals (Cd, Pb, As, Cu, Zn, Fe, Mn) individual We also projected understand prospective...
Fluid sources and flow rates at methane seeps control gas hydrate formation, are potentially archived in authigenic carbonates. Lithium (Li) seeping fluids exhibits a broad range of isotopic fractionation during its ascent to the seafloor, providing information on temperatures fluids. To test applicability Li isotopes as fluid tracer carbonates, this study investigates element isotope composition methane-seep carbonates collected from Black Sea Japan Sea. The Li/Ca ratios δ7Li values...