A5008927496- Geological and Geochemical Analysis
- earthquake and tectonic studies
- High-pressure geophysics and materials
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- Geological and Geophysical Studies
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Radioactive element chemistry and processing
- Geological Studies and Exploration
- Hydrocarbon exploration and reservoir analysis
- Methane Hydrates and Related Phenomena
- Mineralogy and Gemology Studies
- Radioactive contamination and transfer
- Analytical chemistry methods development
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Nuclear Physics and Applications
- Groundwater and Isotope Geochemistry
- Geological Modeling and Analysis
- Laser-induced spectroscopy and plasma
- Planetary Science and Exploration
- Geological formations and processes
- X-ray Spectroscopy and Fluorescence Analysis
Japan Agency for Marine-Earth Science and Technology
2015-2024
Tohoku University
2014-2021
Volcano Corporation (United States)
2020
Tokyo Institute of Technology
2006-2019
Naval Hospital Yokosuka Japan
2014-2018
Society of Exploration Geophysicists
2015
Waseda University
2015
Okayama Prefecture
2015
Shimane University
2001-2014
Iwate University
2014
Recent diving with the JAMSTEC Shinkai 6500 manned submersible in Mariana fore arc southeast of Guam has discovered that MORB‐like tholeiitic basalts crop out over large areas. These “fore‐arc basalts” (FAB) underlie boninites and overlie diabasic gabbroic rocks. Potential origins include eruption at a spreading center before subduction began or during near‐trench after began. FAB trace element patterns are similar to those MORB most Izu‐Bonin‐Mariana (IBM) back‐arc lavas. However, Ti/V Yb/V...
Abstract Zircon OD ‐3 from the P aleogene K awamoto G ranodiorite ( M ihara body) in J apan has been identified as a potential multi‐grain secondary standard for U–Pb dating. We have carried out an inter‐laboratory evaluation order to evaluate possible heterogeneity amongst zircon grains. ages were obtained using two analytical techniques (a sensitive high‐resolution ion microprobe and laser ablation–inductively coupled plasma–mass spectrometry) eight laboratories. All 238 U– 206 Pb show...
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...
Volcanism on Earth is known to occur in three tectonic settings: divergent plate boundaries (such as mid-ocean ridges), convergent island arcs), and hot spots. We report volcanism the 135 million-year-old Pacific Plate not belonging any of these categories. Small alkalic volcanoes form from small percent melts originate asthenosphere, implied by their trace element geochemistry noble gas isotopic compositions. propose that erupt along lithospheric fractures response flexure during...
Quaternary lavas from the NE Japan arc show geochemical evidence of mixing between mantle-derived basalts and crustal melts at magmatic front, whereas significant signals are not detected in rear-arc lavas. The along-arc chemical variations front attributable almost entirely to that were mixed with a common basalt. have slightly enriched Sr–Pb depleted Nd isotopic compositions relative lavas, but variation is less pronounced if contributions eliminated. Therefore, source mantle slab-derived...
Research Article| July 01, 2005 Reinitiation of subduction and magmatic responses in SW Japan during Neogene time Jun-Ichi Kimura; Kimura 1Department Geoscience, Shimane University, Matsue 690-8504, Search for other works by this author on: GSW Google Scholar Robert J. Stern; Stern 2Geosciences Department, University Texas at Dallas, Richardson, 75083-0688, USA Takeyoshi Yoshida 3Institute Mineralogy, Petrology Economic Geology, Tohoku Aobaku, Sendai 980-7763, Author Article Information...
We present major element, trace and petrographic data on alkali basalts from St. Helena, examine the geochemical characteristics of a recycled component involved in source HIMU (206Pb/204Pb >20·5) ocean island basalts. Petrographic compositional variations Helena are best explained by combined effect fractional crystallization accumulation phenocrysts. Primary melt compositions estimated correcting for effects crystal–liquid differentiation reconstructing order relative amount fractionated...
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...
We present major, trace element, and Pb‐Sr‐Nd‐Hf isotope data for Quaternary basalt basaltic andesite lavas from cross‐chain volcanoes in the northern Izu (N‐Izu) arc. Lavas Izu‐Oshima, Toshima, Udonejima, Niijima islands show consistent chemical changes with depth to Wadati‐Benioff zone, 120 km beneath Izu‐Oshima 180 Niijima. at volcanic front (VF) have elevated concentrations of large ion lithophile elements (LILEs), whereas rear‐arc (RA) are rich light rare earth (LREEs) high field...
The extreme Sr, Nd, Hf, and Pb isotopic compositions found in Pitcairn Island basalts have been labeled enriched mantle 1 (EM1), characterizing them as one of the end members. EM1 origin has vigorously debated for over 25 years, with interpretations ranging from delaminated subcontinental lithosphere, to recycled lower continental crust, oceanic crust carrying ancient pelagic sediments, all which may potentially generate requisite radiogenic composition. Here we find that δ26Mg ratios are...
Initial subduction-related boninitic magmatism occurred between 48 and 44 Ma in the Izu–Bonin–Mariana (IBM) arc. High-Mg adakites low-Ca boninites have been dredged from Bonin Ridge fore-arc seamount. Whole-rock 40Ar/ 39Ar ages suggest that boninite (44·0 ± 1·4 Ma) adakite (43·1 1·0 40·8 0·8 overlapped, or slightly later than magmatism. The are high-Mg andesites exhibit U-shaped rare earth element (REE) patterns with an elevated average Mg# of 0·78 [Mg# = Mg/(Mg + Fe) molar ratio] Ni content...
A new olivine reference material – Mong OL Sh11‐2 for in situ analysis has been prepared from the central portion of a large (20 × 20 10 cm) mantle peridotite xenolith ~ 0.5 My old basaltic breccia at Shavaryn‐Tsaram, Tariat region, Mongolia. The is fertile lherzolite with minimal signs alteration. Approximately g 0.5–2 mm gem quality fragments were separated under binocular microscope and analysed by EPMA , LA ‐ ICP MS SIMS bulk analytical methods ( ID Mg Fe, XRF ) major, minor trace...
Research Article| June 01, 2015 Age of Matuyama-Brunhes boundary constrained by U-Pb zircon dating a widespread tephra Yusuke Suganuma; Suganuma * 1National Institute Polar Research, Tachikawa, Tokyo 190-8518, Japan2Department Science, The Graduate University for Advanced Studies (SOKENDAI), Japan *E-mail: suganuma.yusuke@nipr.ac.jp Search other works this author on: GSW Google Scholar Makoto Okada; Okada 3Department Earth Sciences, Ibaraki University, Mito, 310-8512, Kenji Horie; Horie...
A high concentrated glass bead, with a flux to sample ratio of two one, was prepared evaluate the potential for major and trace element analyses various silicate rocks by X-ray fluorescence spectrometry. Careful instrument set up, matrix effect peak overlap corrections allowed enhanced accuracy analysis. The reached level comparable that using five one beads elements pressed powder pellets elements. Using this method, were possible single bead.