A5008295976- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- earthquake and tectonic studies
- Molecular Junctions and Nanostructures
- Crystal Structures and Properties
- Metallurgical Processes and Thermodynamics
- Quantum and electron transport phenomena
- Geomagnetism and Paleomagnetism Studies
- Diamond and Carbon-based Materials Research
- Microstructure and Mechanical Properties of Steels
- Force Microscopy Techniques and Applications
- Surface and Thin Film Phenomena
- Graphene research and applications
- Carbon Nanotubes in Composites
- Thermal Expansion and Ionic Conductivity
- Astro and Planetary Science
- Thermal and Kinetic Analysis
- Thermodynamic and Structural Properties of Metals and Alloys
- Earthquake Detection and Analysis
- Hydrocarbon exploration and reservoir analysis
- Material Properties and Failure Mechanisms
- Organic Electronics and Photovoltaics
- Thermal properties of materials
- Semiconductor materials and interfaces
- Rare-earth and actinide compounds
University of Tsukuba
2015-2025
The University of Tokyo
2015-2025
Life Science Institute
2016-2025
Institute of Science Tokyo
2025
Tokyo Institute of Technology
2015-2024
NEC (Japan)
2014-2024
Earth-Life Science Institute
2015-2023
Mitsubishi Electric (Japan)
1997-2020
Planetary Science Institute
2005-2019
Iwate University
2016-2018
In situ x-ray diffraction measurements of MgSiO 3 were performed at high pressure and temperature similar to the conditions Earth's core-mantle boundary. Results demonstrate that perovskite transforms a new high-pressure form with stacked SiO 6 -octahedral sheet structure above 125 gigapascals 2500 kelvin (2700-kilometer depth near base mantle) an increase in density 1.0 1.2%. The origin D″ seismic discontinuity may be attributed this post-perovskite phase transition. have large elastic...
Earth's solid inner core is mainly composed of iron (Fe). Because the relevant ultrahigh pressure and temperature conditions are difficult to produce experimentally, preferred crystal structure Fe at remains uncertain. Static compression experiments showed that hexagonal close-packed (hcp) stable up 377 gigapascals 5700 kelvin, corresponding conditions. The observed weak dependence c/a axial ratio suggests hcp elastically anisotropic temperatures. Preferred orientation phase may explain...
We have determined the postspinel transformation boundary in Mg 2 SiO 4 by combining quench technique with situ pressure measurements, using multiple internal standards including Au, MgO, and Pt. The experimentally is general agreement previous measurements which Au scale of Anderson et al. [1989] was used to calculate pressure: Using this scale, it occurs at significantly lower pressures compared that corresponding 660‐km seismic discontinuity. In study, we also report new experimental data...
The composition and state of Earth's core, located deeper than 2,900 km from the surface, remain largely uncertain. Recent static experiments on iron alloys performed up to inner core pressure temperature conditions have revealed phase relations properties materials. These mineral physics constraints, combined with theoretical calculations, continue improve our understanding in particular crystal structure chemical composition, thermal evolution, possible stratification outer core.
The melting temperature of Earth's mantle provides key constraints on the thermal structures both and core. Through high-pressure experiments three-dimensional x-ray microtomographic imaging, we showed that solidus a primitive (pyrolitic) is as low 3570 ± 200 kelvin at pressures expected near boundary between outer Because lowermost not globally molten, this an upper bound core-mantle (T(CMB)). Such remarkably T(CMB) implies post-perovskite phase present in wide areas mantle. also requires...
Hydrogen is one of the possible alloying elements in Earth's core, but its siderophile (iron-loving) nature debated. Here we experimentally examined partitioning hydrogen between molten iron and silicate melt at 30-60 gigapascals 3100-4600 kelvin. We find that has a metal/silicate partition coefficient DH ≥ 29 therefore strongly conditions core formation. Unless water was delivered only final stage accretion, formation scenarios suggest 0.3-0.6 wt% H incorporated into leaving relatively...
Research Article| January 01, 1997 Melting experiments on lherzolite KLB-1 under hydrous conditions and generation of high-magnesian andesitic melts Kei Hirose 1Department Earth Planetary Sciences, Tokyo Institute Technology, Ookayama, 152, Japan Search for other works by this author on: GSW Google Scholar Author Article Information Publisher: Geological Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1997) 25 (1): 42–44....
Phase relations in the natural pyrolitic mantle composition (KLB‐1) around 670‐km depth have been determined at 1600–2200°C by high‐pressure experiments using multianvil apparatus. A phase transition between majorite garnet and Al‐bearing Mg‐rich perovskite occurs depths similar to postspinel transition. The seismic discontinuity observed this could be caused a combination of both transitions. majorite‐perovskite boundary has positive Clausius‐Clapeyron slope (+0.0013 GPa/°C for majorite‐out...
New compositional data are presented for recent (<3.5 Ma) basaltic lavas from the Vanuatu arc and North Fiji back-arc, material being subducted at trench. Sr, Nd Pb isotope vary systematically north–south along highlight where D'Entrecasteaux Zone on subducting plate collides with fore-arc. Major trace element show significant lateral variations in enrichment of mantle wedge relative to an N-MORB source. elemental isotopic analyses Loyalty Basin sediments have allowed flux elements be...