A5076595281- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Geological and Geochemical Analysis
- Geological and Geophysical Studies
- Geochemistry and Geologic Mapping
- Paleontology and Stratigraphy of Fossils
- Radioactive element chemistry and processing
- Extraction and Separation Processes
- Hydrogen embrittlement and corrosion behaviors in metals
- Fusion materials and technologies
- Geological Studies and Exploration
- Geological formations and processes
- Isotope Analysis in Ecology
- Nuclear Materials and Properties
- Forensic Anthropology and Bioarchaeology Studies
- Pleistocene-Era Hominins and Archaeology
- Metal and Thin Film Mechanics
- Geomagnetism and Paleomagnetism Studies
- earthquake and tectonic studies
- Advanced Materials Characterization Techniques
- Hydrocarbon exploration and reservoir analysis
- Corrosion Behavior and Inhibition
- Bauxite Residue and Utilization
- High-Temperature Coating Behaviors
Chiba Institute of Technology
2018-2025
The University of Tokyo
2014-2025
Japan Agency for Marine-Earth Science and Technology
2016-2025
National Institute of Advanced Industrial Science and Technology
2024
Frontier Energy (United States)
2018-2023
Central Research Institute of Electric Power Industry
1998-2004
Engineering (Italy)
2002
Argonne National Laboratory
2002
Office of Scientific and Technical Information
2002
Electric Power Research Institute
2000
Potential risks of supply shortages for critical metals including rare-earth elements and yttrium (REY) have spurred great interest in commercial mining deep-sea mineral resources. Deep-sea mud containing over 5,000 ppm total REY content was discovered the western North Pacific Ocean near Minamitorishima Island, Japan, 2013. This REY-rich has potential as a metal resource because enormous amount available its advantageous mineralogical features. Here, we estimated with Geographical...
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...
Abstract A certain type of deep‐sea sediment exhibits very high content rare earth elements and yttrium (REY) is therefore expected to serve as a novel resource for these industrially essential metals. In this paper, we statistically analyzed the bulk chemical composition sediments collected from western North Pacific Ocean. By applying independent component analysis multielemental data set, extracted three components (ICs) that can be interpreted influence Mn‐oxides (IC1), REY‐enriched...
Abstract Microfossils of fish teeth and denticles, referred to as ichthyoliths, provide critical information for depositional ages, paleo‐environments, marine ecosystems, especially in pelagic realms. However, owing their small size rarity, it is time‐consuming difficult analyze large numbers ichthyoliths from sediment samples, limiting use scientific studies. Here, we propose a method automatically detect microscopic images using deep learning technique. We applied YOLO‐v7, one the latest...
We analyzed 1338 deep-sea sediment samples from 19 Deep Sea Drilling Project/Ocean Program sites covering a large portion of the Indian Ocean, and constructed new comprehensive data set their bulk chemical compositions, including rare-earth, major, trace elements. The bulk-sediment rare-earth yttrium (REY) composition REY-enriched samples, characterized by relatively small negative Ce anomalies, almost no Y enrichment in heavy elements, can be interpreted as superposition REY compositions...
Seven piston cores were collected from the seafloor ~250 km south of Minamitorishima Island in western North Pacific Ocean during cruise KR13-02 R/V Kairei; some portions PC04 and PC05, total contents rare-earth elements yttrium (∑REY) exceeded 4,000 ppm. Microscopic observations showed that highly REY-enriched layers (∑REY > ~2,000 ppm) contained significant amounts calcium phosphate phillipsite. We conducted microscopic grain size distribution analyses bulk sediments distinctive components...
We report detailed lithological and chemical characteristics of deep-sea sediments, including rare-earth elements yttrium-rich mud (REY-rich mud), in the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island. Three research cruises obtained fourteen sediment cores collected by piston coring. Based on visual descriptions geochemical analysis cores, we confirm presence REY-rich containing more than 400 ppm total REY (∑REY) southern northwestern areas EEZ. The layers are...
Scandium is a critical element in state-of-the-art, green technologies. However, it also extremely expensive due to its scarcity. Recently, some deep-sea sediments that contain significant amounts of rare-earth elements are indispensable modern industries have been discovered the western North Pacific Ocean, and concentration Sc these comparable with land-based mines. A simple leaching experiment has demonstrated up 70% sediments, contained within biogenic calcium phosphate particles, can be...
Rare earth element and yttrium (REY)-rich mud around Minamitorishima Island, Japan, in the western North Pacific Ocean has received significant attention as a novel REY resource. In REY-rich muds, industrially critical metals such Co, Ni, Mo occur relatively high concentrations. We show that Fe-Mn micronodules separated from muds are significantly enriched these elements; we measured Co contents of almost 3000 ppm Ni exceed 39,000 ppm. Through experiments, demonstrated reductive chemical...
Abstract The deep-sea clay that covers wide areas of the pelagic ocean bottom provides key information about open-ocean environments but lacks age-diagnostic calcareous or siliceous microfossils. marine osmium isotope record has varied in response to environmental changes and can therefore be a useful stratigraphic marker. In this study, we used ratios determine depositional ages clays extraordinarily rich fish debris. Much debris was deposited western North central South Pacific sites...
Deep-sea mud enriched in rare-earth elements and yttrium (REY-rich mud) has been recognized as a new resource for REY scandium (Sc). Recently, highly REY-rich with more than 2,000 ppm of was found the western North Pacific Ocean. The high content attributed to enhanced deposition fish debris, which acts host REY, resulting from proliferation caused by topographically induced upwelling nutrients. To investigate spatial extent mud, we conducted mineralogical chemical analyses on selected...
Abstract Deep‐sea mud enriched in rare‐earth elements (REE), termed REE‐rich mud, is a promising seafloor mineral resource. Data from decade of surveys have revealed that the with highest REE concentration occurs pelagic realm western North Pacific Ocean, at least two layers elevated concentration. Previous analyses sediments multiple periods significant enrichment, younger enrichment triggered by global cooling during Eocene–Oligocene climate transition. However, depositional mechanism...
Deep-sea sediments with total rare-earth elements and yttrium (ΣREY) concentrations exceeding 400 ppm, which are termed REY-rich mud, widely distributed in the world oceans. Specifically, deep-sea within Japanese exclusive economic zone (EEZ) surrounding Minamitorishima Island western North Pacific have attracted significant attention as a new REY resource, because they contain REY-enriched layers 2000 ppm of ΣREY. However, neither deeper than 15 m below seafloor (mbsf) nor those outside EEZ...
Microfossil fish teeth, known as ichthyoliths, provide a key constraint on the depositional age and environment of deep-sea sediments, especially pelagic clays where siliceous calcareous microfossils are rarely observed. However, traditional methods for observation ichthyoliths require considerable time manual labor, which can hinder their wider application. In this study, we constructed system to automatically detect in microscopic images by combining two open source deep learning models....
Abstract The Ruwai skarn deposit is the largest polymetallic in Borneo and located Schwaner Mountains. skarns massive orebodies are hosted marble of Jurassic Ketapang Complex, which was intruded by Cretaceous Sukadana granitoids. prograde-stage garnet retrograde-stage titanite yielded U-Pb ages 97.0 ± 1.8 to 94.2 10.3 Ma 96.0 2.9 95.0 2.0 Ma, respectively. These similar Re-Os obtained on sulfides (96.0 2.3 Ma) magnetite (99.3 3.6 Ma). zircon reveal that magmatism at occurred three phases,...
Abstract Deep‐sea sediments enriched in rare‐earth elements and yttrium (REY) plus scandium (Sc), termed “REY‐rich mud,” have attracted attention as a possible resource for these critical industrial elements. Examples been reported from the western North Pacific, central low‐latitude South eastern Pacific. Although previous studies of pelagic clay existence highly REY‐rich mud ultraoligotrophic Pacific Gyre, neither source materials nor potentials REY Sc sediment quantified. We analyzed...
Abstract Deep‐sea sediments around Minamitorishima Island in the western North Pacific Ocean record depositional environment central to since late Cretaceous. Previous studies on bulk chemical composition of deep‐sea this area have revealed that sediment column can be divided into five chemostratigraphic units with at least three intercalated layers enriched rare‐earth elements. However, end‐member components and their changes abundance, which indicate compositional variation, as well...
Multiple short-term (<105 years) global warming events ("hyperthermals") occurred throughout the early Eocene. Chemical weathering of continental silicate rocks is considered to have played a key role in recovery from these transient via consumption excess atmospheric CO2. However, although evidence this negative feedback has been reported for Paleocene–Eocene Thermal Maximum (PETM), effectiveness chemical during other hyperthermals remains poorly constrained. Here, we newly report Eocene...
Abstract Meteorite impacts have caused catastrophic perturbations to the global environment and mass extinctions throughout Earth’s history. Here, we present petrographic geochemical evidence of a possible impact ejecta layer, dating from about 11 Ma, in deep-sea clayey sediment Northwest Pacific. This clay layer has high platinum group element (PGE) concentrations features conspicuous negative Os isotope anomaly ( 187 Os/ 188 as low ~0.2), indicating an influx extraterrestrial material. It...
The origin of deep-sea sediments in the western North Pacific Ocean, which are significantly enriched rare-earth elements and yttrium (REY), its paleoceanographic implications have been poorly constrained. Here, we investigated stratigraphic variations chemical compositions textures ferromanganese (Fe–Mn) micronodules separated from sediments. characteristics an extremely REY-rich mud layer vary almost purely diagenetic to relatively hydrogenetic. This indicates abundant supply organic...
The direct observation of crystal structure at ultra-low temperatures helps better understanding phase transformations and stability. Two sets 3He-4He dilution refrigerators with a top-loading facility were installed BL-3C2 6C1 the Photon Factory. first is used exclusively for topography quantum crystals solid 3He 4He studies lattice defects. Typical examples topographs that indicate an annealing effect helium, understood in terms tunneling, are presented. disappearance downward diffraction...