A5079480777- Geological and Geochemical Analysis
- earthquake and tectonic studies
- High-pressure geophysics and materials
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Geological and Geophysical Studies
- Geological Studies and Exploration
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- Seismic Imaging and Inversion Techniques
- Paleontology and Stratigraphy of Fossils
- Geomagnetism and Paleomagnetism Studies
- Hydrocarbon exploration and reservoir analysis
- Reservoir Engineering and Simulation Methods
- Astro and Planetary Science
- Geological formations and processes
- Marine and environmental studies
- Geological and Geophysical Studies Worldwide
- CO2 Sequestration and Geologic Interactions
- Geophysical and Geoelectrical Methods
- Geotechnical and Geomechanical Engineering
- Thermal and Kinetic Analysis
- Geochemistry and Geochronology of Asian Mineral Deposits
- Isotope Analysis in Ecology
- Global Energy and Sustainability Research
Tohoku University
2015-2024
Center for Southeast Asian Studies
2010-2017
Graduate School USA
2017
Kanazawa University
2010
The University of Tokyo
2003-2008
Tokyo Institute of Technology
2003-2007
University of Hawaii System
2006
University of California, San Diego
2006
Scripps Institution of Oceanography
2006
Japan Agency for Marine-Earth Science and Technology
2006
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...
A dense field of ferromanganese (Fe-Mn) nodules was discovered on a seamount approximately 300 km east Minamitorishima Island, in the Japanese Exclusive Economic Zone. To evaluate its potential as resource for critical metals, we describe results geological survey using SHINKAI 6500 submersible (dive No. 6K 1207) during cruise YK10-05 R/V Yokosuka 2010, and geochemical analyses collected samples. Submersible observations showed that spherical 5–10 cm diameter almost fully cover region high...
Research Article| January 01, 2010 Mechanisms of low-flux intraplate volcanic fields—Basin and Range (North America) northwest Pacific Ocean Greg A. Valentine; Valentine * 1Department Geology, University at Buffalo, 411 Cooke Hall, New York 14260, USA *E-mails: gav4@buffalo.edu; nhirano@cneas.tohoku.ac.jp. Search for other works by this author on: GSW Google Scholar Naoto Hirano 2Center Northeast Asian Studies, Tohoku University, 41 Kawauchi, Sendai 980-8576, Japan Author Article Information...
One extremely young volcano (0.05–1 Ma) and other volcanoes (1.8, 4.2, 6.0, 8.5 composed of strongly alkaline magma were recently discovered on the abyssal plain Early Cretaceous (135 Pacific Plate. These dubbed “petit-spots”. The petit-spot volcanic province represents more than 8 Myr activity over a large area (~600 km along direction plate motion), but with relatively small volume production, thus indicating supply heat inconsistent hotspot. low-flux may be related to occurrence tensional...
Abstract. Petit-spot volcanoes, occurring due to plate flexure, have been reported globally. As the petit-spot melts ascend from asthenosphere, they provide crucial information of lithosphere–asthenosphere boundary. Herein, we examined lava outcrops six monogenetic volcanoes formed by volcanism in western Pacific. We then analyzed 40Ar/39Ar ages, major and trace element compositions, Sr, Nd, Pb isotopic ratios basalts. The ages two were ca. 2.6 Ma (million years ago) 0 Ma. compositions...
ABSTRACT On the western part of Pacific Plate most seamounts formed during Cretaceous period in so‐called West Seamount Province (WPSP). northwestern same plate, Joban and Japanese Trail (JJST) are also composed Early seamounts. However, two new groups knolls were recently discovered multibeam surveys on along Japan Trench. One group consists circular that flat‐topped shape correspond to eruptive ages approximately 75 Ma. The other irregularly shaped knolls, called petit‐spot volcanoes,...
In 2009, petit-spot submarine volcanoes were discovered off the oceanward slope of central Chile trench, offshore from Valparaiso, Chile, at around 33°S. Ar-Ar dating mugearite and alkali-basalt yields ages 10.11 ± 0.22 Ma 6.69 0.88 Ma, respectively. Back-calculations plate motion along present absolute movement direction Nazca Plate, conducted using age data, indicate that eruption occurred above a zone flexure. The back-calculation results suggest was erupted flexural arch prior to arrival...
Research Article| November 01, 2014 Melt-rich lithosphere-asthenosphere boundary inferred from petit-spot volcanoes Junji Yamamoto; Yamamoto 1The Hokkaido University Museum, 8 Nishi, 10 Kita, Kita-ku, Sapporo 060-0810, Japan2Institute for Geothermal Sciences, Kyoto University, Noguchibaru, Beppu 874-0903, Japan Search other works by this author on: GSW Google Scholar Jun Korenaga; Korenaga 3Department of Geology and Geophysics, Yale P.O. Box 208109, New Haven, Connecticut 06520-8109, USA...
Abstract The source mantle of the basaltic ocean crust on western half Pacific Plate was examined using Pb‐Nd‐Hf isotopes. results showed that subducted Izanagi‐Pacific Ridge (IPR) formed from both (180–∼80 Ma) and Indian (∼80–70 mantles. becomes younger westward is thought to have IPR. ridge along Kurile‐Japan‐Nankai‐Ryukyu (KJNR) Trench at 60–55 Ma leading edge currently stagnated in transition zone. Conversely, entire eastern Plate, isotopically distinct East Rise Juan de Fuca Ridge,...
The deep carbon cycle plays an important role on the chemical differentiation and physical properties of Earth's mantle. Especially in asthenosphere, seismic low-velocity high electrical conductivity due to dioxide (CO2)-induced partial melting are expected but not directly observed. Here we discuss experimental results relevant genesis primitive CO2-rich alkali magma forming petit-spot volcanoes at deformation front outer rise northwestern Pacific plate. suggest that melt last equilibrated...
Abstract Petit-spot volcanoes provide a unique opportunity to directly examine the structure and geochemical composition of lithospheric asthenospheric mantle beneath subducting oceanic crust. Currently, petit-spot volcanos—formed in response flexure plates—are known exist off Japan, Java, Chile Mariana trenches, however, difficulties associated with detecting them leaves possibility that they may be more widespread along outer rise plates. Investigation lavas xenolithic material erupted...
The oceanic lithosphere cools as it spreads away from the mid-ocean ridges, and subducts into mantle at subduction zones. In context of Earth’s material cycle, quantitative chemical thermal state is desired to be estimated elucidate flux mantle. As a step toward reconstructing lithosphere, we present geochemical data set xenoliths petti-spots in northwestern Pacific, where no seismic anomaly imaged. petit-spot-borne provide us unique information avoiding modifications derived...
Alkali pillow basalts were collected from the toe of oceanward slope northern Japan Trench. These alkali‐basalts formed as a result low degree partial melting Pacific Ocean mantle and rapid rise magma (no fractionation in shallow chambers). Reconstructing Plate motion based on 40 Ar‐ 39 Ar age dates 5.95±0.31 Ma for these indicates that they erupted outboard outer swell or forebulge Trench NW Pacific. We suggest represent new form intra‐plate volcanism, whereby magmatic activity occurs off...
Research Article| July 01, 2007 Depleted mantle wedge and sediment fingerprint in unusual basalts from the Manihiki Plateau, central Pacific Ocean Stephanie Ingle; Ingle 1Department of Earth Planetary Sciences, Tokyo Institute Technology, 152-8551, Japan Search for other works by this author on: GSW Google Scholar John J. Mahoney; Mahoney 2School Science University Hawaii, Honolulu, Hawaii 96822, USA Hiroshi Sato; Sato 3School Business Administration, Senshu University, Kanagawa 214-8580,...
Seafloor magnetotelluric (MT) experiments were recently conducted in two areas of the northwestern Pacific to investigate nature old oceanic upper mantle. The are far from any tectonic activity, and "normal" mantle structure is therefore expected. data carefully analyzed reduce effects coastlines seafloor topographic changes, which significant boundaries electrical conductivity thus distort MT data. An isotropic, one-dimensional profile was estimated for each area. profiles compared with...
Large amounts of CO2 are transferred from Earth’s interior to the surface by volcanism. On a geological time scale, rate emission has controlled evolution atmosphere and climate, as well dynamic processes that take place in mantle core. The total natural Earth been estimated on basis flux arc, mid-ocean-ridge, hotspot However, previous estimates have overlooked emitted recently discovered type volcanism—petit-spot volcanism—that occurs deep-sea floor. Here, we measure H2O contents glassy...
Abstract The West Pacific Seamount Province (WPSP) represents a series of short‐lived Cretaceous hotspot tracks. However, no intraplate volcanoes in advance petit‐spot volcanism erupted near trench have been identified after the formation WPSP on western Plate. This study reports new ages for Paleogene volcanic edifices within northern WPSP, specifically Ogasawara Plateau and related ridges, Minamitorishima Island. These are first reported basaltic rocks seamounts, an area that has...