Kentaro Terada

Kentaro Terada
Osaka University | Handai

About

179
Publications
13,925
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,267
Citations
Citations since 2016
35 Research Items
2310 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Additional affiliations
July 1994 - March 2012
Hiroshima University
Position
  • permsnent

Publications

Publications (179)
Article
Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the protoplanetary disk. Here we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, t...
Article
Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed seventeen Ryugu samples measuring 1-8 mm. CO2-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that forme...
Preprint
We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anoma...
Article
Full-text available
We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXAʼs Hayabusa2 mission. We report the detection of all major presolar grain types with O-and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomal...
Article
Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to carbonaceous chondrite meteorites, par...
Article
Attempts to improve the accuracy in measuring diamagnetic susceptibility χ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DIA</sub> of a small particle are conducted by measuring its magnetic translation. In this study, accuracy improvement was pursued by two different experiments. First, translation...
Article
Diamagnetic susceptibility $\chi _{\mathrm {DIA}}$ of a small particle is determined from its parabolic translation induced by a field gradient generated by a pair of neodymium magnet in normal gravity condition. Specifically, $\chi _{\mathrm {DIA}}$ of a single particle is determined from the relationships between velocity $v(x_{i})$ of part...
Article
To investigate the chemical effect on the muon capture process through a muon transfer reaction from a muonic hydrogen atom, the formation rate of muonic carbon atoms is measured for benzene and cyclohexane molecules in liquid samples. The muon transfer rate to carbon atoms of the benzene molecule is higher than that to the carbon atoms of the cycl...
Article
Full-text available
Meteoroid bombardment of the Earth-Moon system must have caused catastrophic damage to the terrestrial ecosphere. However, ancient meteoroid impacts and their relations to environmental changes are not well understood because of erosion and/or resurfacing processes on Earth. Here, we investigate the formation ages of 59 lunar craters with fresh mor...
Article
Full-text available
Carbon is a volatile element that has a considerable influence on the formation and evolution of planetary bodies, although it was previously believed to be depleted in the Moon. We present observations by the lunar orbiter KAGUYA of carbon ions emitted from the Moon. These emissions were distributed over almost the total lunar surface, but amounts...
Article
Magentic separation generally required strong magnetic forces induced in ferromagnetic or strong paramagnetic particles; in order to realize the separation in diamagnetic or weak paramagnetic particles, it was necessary to attach magnetic beads or magnetic ions to induce the strong magnetic force. A method to separate mixture of weak magnetic parti...
Article
Simultaneous ion counting and waveform averaging implemented on a field-programmable gate array compiled with a high-speed digitizer was applied to ultra-performance liquid chromatography-time-of-flight mass spectrometric analysis of sulfa drugs. Ion counting was carried out by a “Peak Detection” (PKD) function that works together with signal avera...
Article
Translation of binary-mixture particles composed of solid CO2 and graphite were observed in an area of static magnetic-field that monotonically decreased in one direction, and magnetic susceptibility χmix of individual particle was determined from the observed relationship between translating velocity and field intensity. Using the variance of χmix...
Article
An elemental analysis method utilizing muons has been demonstrated to be effective for non-destructive and quantitative analysis of precious bulk materials. In muon capture process, molecular structure dependence was known, and this property has the potential to be used to identify chemical structure in addition to elemental composition. Before the...
Article
Full-text available
Muon Science Innovative muon beam Channel (MuSIC) at Research Center for Nuclear Physics (RCNP), Osaka University have been constructed and started muon beam generation from 2013, and now, full beam operation is available. We analyzed elemental composition of the Tempo-koban (19th century, Japan), which is covered by a copper plate, by muonic X-ray...
Article
Variations in isotopic abundance provide useful information for various scientific fields. Herein we performed a feasibility study by non-destructive isotopic analysis of negative muons. We irradiated two lead plate samples, one with the natural isotopic composition and one enriched with ²⁰⁸Pb, with negative muons and observed the gamma rays from ²...
Article
The quantitative accuracy and throughput performance for the newly developed hardware-based simultaneous ion counting and waveform averaging (AVG) in a time-of-flight (TOF) mass spectrometer was studied. The peak detection (PKD) algorithm was used for ion counting instead of voltage threshold detection method that is widely used in ion counting tec...
Article
Full-text available
Elemental isotopic ratios are measured in various research fields and provide useful information regarding age, origin, geological and biological activities, ancient climate, etc. Here, we report a new isotopic analysis method without sample destruction using muon-induced characteristic X-rays. We demonstrated this method by conducting muon-beam ir...
Article
We designed an improved apparatus to separate and identify volatile solid particles at temperatures around 200 K using short-duration microgravity. Separation is based on the difference in diamagnetism of the mixed particles released in a region of monotonically decreasing magnetic field. The velocity of the translating particles in the microgravit...
Article
Full-text available
Most solid particles, composed of diamagnetic or weak paramagnetic materials, cannot be extracted by a conventional magnetic separator. Here we report that an ensemble of heterogeneous particles, composed of bismuth, gold, graphite and rock forming minerals are separated into fractions of different materials by small NdFeB magnetic plates. It is ba...
Article
The enriched basaltic (martian) shergottite Ksar Ghilane (KG) 002, discovered in 2010, is exceptionally rich in coexisting but discrete apatite and merrillite crystals. It has been selected to better constrain the formation conditions and post-crystallization processes, and thus the evolution of martian rocks based on Ca-phosphates. A petrological,...
Article
Full-text available
Understanding the origin and evolution of near-Earth asteroids (NEAs) is an issue of scientific interest and practical importance because NEAs are potentially hazardous to the Earth. However, when and how NEAs formed and their evolutionary history remain enigmas. Here, we report the U-Pb systematics of Itokawa particles for the first time. Ion micr...
Article
Two different types of data acquisition methods, “averaging mode” and “ion-counting mode”, have been used in a time-of-flight (TOF) mass spectrometry. The most common method is an averaging mode that sums waveform signals obtained from each flight cycle. While it is possible to process many ions arriving at the same TOF in one flight cycle, low-abu...
Article
Full-text available
Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high t...
Article
A comprehensive study of the organic chemistry and mineralogy of an ultracarbonaceous micrometeorite (UCAMM D05IB80) collected from near the Dome Fuji Station, Antarctica, was carried out to understand the genetic relationship among organic materials, silicates, and water. The micrometeorite is composed of a dense aggregate of ∼5 µm-sized hollow el...
Article
Micrometeorites (MMs) recovered from surface snow near the Dome Fuji Station, Antarctica are almost free from terrestrial weathering and contain very primitive materials, and are suitable for investigation of the evolution and interaction of inorganic and organic materials in the early solar system. We carried out a comprehensive study on seven por...
Article
For five days of each lunar orbit, the Moon is shielded from solar wind bombardment by the Earth’s magnetosphere, which is filled with terrestrial ions. Although the possibility of the presence of terrestrial nitrogen and noble gases in lunar soil has been discussed based on their isotopic composition 1 , complicated oxygen isotope fractionation in...
Article
Full-text available
Most existing solids are categorised as diamagnetic or weak paramagnetic materials. The possibility of magnetic motion has not been intensively considered for these materials. Here, we demonstrate for the first time that ensembles of heterogeneous particles (diamagnetic bismuth, diamond and graphite particles, as well as two paramagnetic olivines)...
Article
The Meghalaya Plateau and the Mikir Hills constitute a northeastern extension of the Precambrian Indian Shield. They are dominantly composed of Proterozoic basement granite gneisses, granites, migmatites, granulites, the Shillong Group metasedimentary cover sequence, and Mesozoic-Tertiary igneous and sedimentary rocks. Medium to coarse grained, equ...
Article
Full-text available
We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that the noble gases in these MMs are mostly of solar...
Conference Paper
Introduction: The abundance and evolution of volatiles in Mar-tian magmas is crucial for understanding the volatile cycle and degassing processes on Mars over time. Martian meteorite paren-tal magmas probably contained up to/or >1 wt% water [e.g., 1-3]. Evidence can be derived from the phosphate chemistry that acts as a monitor of the pre-eruptive...
Article
Full-text available
The recent development of the intense pulsed muon source at J-PARC MUSE, Japan Proton Accelerator Research Complex/MUon Science Establishment (10(6) s(-1) for a momentum of 60 MeV/c), enabled us to pioneer a new frontier in analytical sciences. Here, we report a non-destructive elemental analysis using µ(-) capture. Controlling muon momentum from 3...
Article
We found a micrometeorite with unique mineralogy. It is composed of an aggregate of sub-micrometer-sized almost Fe-free low-Ca pyroxene, Fe-poor olivine, Fe-Ni metal, Fe sulfide, with a small amount of amorphous silicate and carbonaceous material.
Article
In order to understand the origin and evolution of primitive organic materials in the early solar system, we have studied ultracarbonaceous micrometeorite (UCMM) collected from Antarctic. It is about ten microns across on a cut surface, irregularly shaped, and accompanied by GEMs like materials. It's composition is N-rich C. It may be a product of...
Article
We identified Ni-bearing pyrrhotite and GEMS-like objects without metal from an ultracarbonaceous micrometeorite containing large, nitrogen-rich organics.
Article
Bulk mineralogy and chemistry of four MMs from Antarctic surface snow were investigated. Their element compositions are different from MMs from Antarctic ice.
Article
Full-text available
A ten micron-sized organic material of coexisting nitrogen-rich and poor regions was identified in the ultracarbonaceous Antarctic micrometeorite. Some of the organic features were similar to those of several Comet Wild 2 particles and CR3 chondrite.
Article
Lunar meteorites provide a wider sampling of the lunar surface compared to the samples collected during the Apollo and Luna Missions. Apatite is the main hydroxyl-bearing (proxy for water) mineral in lunar samples, especially in basaltic rocks. Apatite is also amenable to in-situ U-Pb age dating studies. The ages of lunar basaltic meteorites also s...
Article
An ultracarbonaceous micrometeorite (UCMM) has been investigated using isotope microscopy, FIB-SEM, STXM, and TEM. C- and N-XANES spectra of N-rich organic region in the UCMM were similar to those of several Comet Wild 2 dust particles.
Article
The Sensitive High Resolution Ion MicroProbe (SHRIMP) is the first ion microprobe dedicated to geological isotopic analyses, especially in-situ analyses related to the geochronology of zircon. Such a sophisticated ion probe, which can attain a high sensitivity at a high mass resolution, based on a double focusing high mass-resolution spectrometer,...
Article
Abstract— We report ion microprobe U-Th-Pb dating of Shergotty phosphates by means of the sensitive high-resolution ion microprobe (SHRIMP) recently installed at Hiroshima University, Japan. ten analyses of whitlockite (merrillite) and three analyses of apatite indicate a 238u/206pb isochron age of 225 ± 200 ma and a tera-wasserburg concordia-const...
Article
Abstract— Phosphates in martian meteorites are important carriers of trace elements, although, they are volumetrically minor minerals. PO4 also has potential as a biomarker for life on Mars. Here, we report measurements of the U-Th-Pb systematics of phosphates in the martian meteorite ALH 84001 using the Sensitive High Resolution Ion MicroProbe (SH...
Article
Abstract— U, Th, and Pb isotopes and rare earth elements (REEs) in individual phosphate grains from martian meteorites Lafayette and Yamato-000593/000749 were measured using a sensitive high-resolution ion microprobe (SHRIMP). Observed U-Pb data of 12 apatite grains from Yamato (Y-) 000593/000749 are well represented by linear regressions in both “...
Article
Full-text available
Zircon U-Pb geochronology was applied to a migmatitic gneiss in the Busan gneiss complex, Gyeonggi massif, Korea. 207Pb/206Pb ages of concordant zircon grains reveal that overgrowth rims with Th/U ratios lower than 0.1 formed at 1937 ± 6 Ma during the migmatization and mantled the inherited cores of ca. 3500–2200 Ma. The 207Pb/206Pb age of the rims...
Article
Full-text available
Constraining the timescales for the evolution of planetary bodies in our solar system is essential for a complete understanding of planet-forming processes. However, frequent collisions between planetesimals in the early solar system obscured and destroyed much of the primitive features of the old, first-generation planetary bodies. The presence of...
Article
We report SHRIMP U–Pb age of zircons in four samples of eclogite and one sample of orthogneiss from Sulu ultrahigh-pressure (UHP) zone in Yangkou area, eastern China. UHP rocks are distributed along the Sulu orogenic belt suturing North China Block with South China Block. In Yangkou area, UHP unit is well exposed for about 200 m along Yangkou beach...
Article
Radiometric ages of detrital zircons in three samples of psammitic schists from the Sanbagawa Belt, Kanto- Mountains, were obtained from the 238U/206Pb ratio and isotopic compositions of Pb using a Sensitive High Resolution Ion MicroProbe (SHRIMP 11). Most of the zircon ages cluster around Cretaceous, with a few ages corresponding to older zircons....
Article
Full-text available
New ion probe isotopic measurements of carbon trapped within the 50 nm thick surface layer of lunar regolith grains strongly suggest that solar wind C is depleted in 13C by at least 10% relative to terrestrial C. In order to account for the general 13C enrichment of planetary C relative to solar C, we propose that the main carriers of C in these ob...
Article
Abstract The Maizuru terrane, distributed in the Inner Zone of southwest Japan, is divided into three subzones (Northern, Central and Southern), each with distinct lithological associations. In clear contrast with the Southern zone consisting of the Yakuno ophiolite, the Northern zone is subdivided into the western and eastern bodies by a high-angl...
Article
Highly metasomatized apatite-rich peridotite layers (AP-layer) occur in the Finero phlogopite–peridotite massif (western Italian Alps). The AP-layer and the host peridotite are characterized by higher concentration of REE (total REE > 80ppm), especially LILE, and lower HFSE, than those of the other rocks in the Finero massif. The AP-layers and thei...
Article
Dhofar 287 is a lunar meteorite found in Oman in 2001, which consists of a major portion (95%) of low-Ti mare basalt (Dho 287A) and a minor attached part (∼ 5%) of regolith breccia (Dho 287B). Here, we report the U–Pb systematics of Dho 287A using data collected with a Sensitive High Resolution Ion Microprobe (SHRIMP). In-situ analyses of five merr...
Article
Full-text available
One of the important issues in lunar science relates to the understanding of the timing and duration of mare magmatism which has significant implications for the thermal evolution of the lunar interior through time. Remote sensing studies of the Moon have indicated existence of mare regions as old as 4 Ga and as young as 1 Ga. In contrast, most lab...
Article
Full-text available
Most studies of lunar rocks and soils have been conducted on samples collected by the Apollo and Luna missions, but these represent samples from near-equatorial regions of the near side of the Moon. However, recent discoveries of lunar meteorites, which have been blasted off the Moon only to land in the hot desserts and Antarctic ice fields of Eart...
Article
Full-text available
The origin and evolution of the Moon remain controversial1, 2, with one of the most important questions for lunar evolution being the timing and duration of basaltic (mare) magmatism1, 3, 4, 5, 6, 7, 8. Here we report the result of ion microprobe U–Pb dating of phosphates in a lunar meteorite, Kalahari 009, which is classified as a very-low-Ti mare...
Article
Combined petrographic, structural and geochronological study of the Malashan dome, one of the North Himalayan gneiss domes, reveals that it is cored by a Miocene granite, the Malashan granite, that intruded into the Jurassic sedimentary rocks of Tethys Himalaya. Two other granites in the area are referred to as the Paiku and Cuobu granites. New zir...
Article
A zircon ‘microvein’ composed of several hundred crystals occurs in peralkaline granitic gneiss of western Ethiopian Precambrians. U–Pb ages and trace element (U, Th, Hf, Y, REE, P, Ca, Al, Fe, and Mn) abundances of the ‘microvein’ and host granitic gneiss zircon were determined using a sensitive high mass resolution ion microprobe (SHRIMP) and ele...
Article
Chronological studies of brecciated lunar meteorites have proved difficult, because they are mixtures of materials from various sources and the radiometric “clocks” are sometimes affected by the subsequent impact events on the Moon. Here, we report the in-situ U–Pb dating of phosphates in lunar meteorite, Meteorite Hills (MET) 01210, which is a reg...
Article
We obtained the radiometric ages of detrital zircons from two samples of paragneiss from Oki-Dogo Island, Japan, from the U-238/Pb-206 ratio and isotopic composition of Pb determined using a Sensitive High-Resolution Ion MicroProbe (SHRIMP II). The zircons show two main age clusters around 2200 Ma and 1800 Ma, with some discordant ages. One zircon...
Article
We present petrographic and geochemical data on representative samples of the Devonian adakite, boninite, low-TiO2 and high-TiO2 basalts and associated rocks in the southern Altay areas, Xinjiang, NW China. These volcanic rocks mostly occur as tectonic blocks within suture zones between the Siberian and Junggar plates. Adakite occurs in the Suoerku...
Article
Europium isotopic composition could be a good probe to investigate the neutron capture process in Asymptotic Giant Branch stars (AGB stars) and/or supernovae, because the 151Sm and 153Sm branchings are sensitive to the neutron densities and temperature. Here, we report Eu isotopic analyses of single SiC grains from primitive meteorites using the se...
Article
We report Eu isotopic analyses of single SiC grains from primitive meteorites using the Sensitive High Resolution Ion Microprobe. The results are compared with Eu isotopic ratios predicted from the recently determined 151Sm(n, gamma) cross sections and the thermally pulsed s-process model of AGB stars. The observed Eu isotopic compositions of SiC g...
Article
The lunar meteorites have been valuable sources for understanding the evolution of the Moon's crust. In this paper, we report ion microprobe U-Pb isotopic analyses of the phosphates in brecciated lunar meteorite Yamato 981031, which includes VLT mare basalt.
Article
The polymict Kamiaso Conglomerate (Mino Terrane, Japan) contains Jurassic to Palaeoproterozoic clasts—probably derived from Korean basement that lay nearby to the northwest at time of deposition. Clast K2 broke cleanly into two halves during sampling (but the halves were recombined for zircon separation). A third of the K2 zircons are colourless eu...
Article
LaPaz Icefield 02205 (LAP 02205) is a new low-Ti mare-basalt meteorite that was discovered in the LaPaz Ice Field in Antarctica. This is the first crystalline lunar basalt in the US Antarctic collection and the only 5th unbrecciated mare-basalt meteorite to be discovered to date. The rock has a typical basaltic texture with tabular and elongated py...
Article
Full-text available
Ion microprobe U-Pb dating of apatite is applied to a fossil tooth of a Allosaurid derived from the Hasandong Formation in the Gyeongsang basin, southeastern Korea. Twelve spots on a single fragment of the fossil dentine yield a TeraWasserburg concordia intercept age of 115 ± 10 Ma (2σ, MSWD = 0.59) on a 238U/206Pb-207Pb/206Pb- 204Pb/206Pb diagram....
Article
Radiometric ages of zircons in psammitic rocks from the Nishiki and Tsuno groups were determined from 238U/206Pb ratio and isotopic compositions of Pb which are analyzed by Sensitive High Resolution Ion Microprobe (SHRIMP II). Detrital zircons in the Nishiki sandstones show a continuous distribution from 320 Ma to 240 Ma, which is similar to those...
Article
We combine zircon sensitive high-resolution ion microprobe U-Pb spot dating and mica 40Ar-39Ar plateau ages with field-geological and geochemical constraints from the Mala shan area of Southern Tibet to show that the deformed granite core of the North Himalayan metamorphic domes in this area is not Indian basement, but was intruded and deformed dur...
Article
We report ion microprobe U-Pb dating of phosphates in lunar meteorite ``Elephant Moraine 87521 (EET87521),'' which is a fragmental breccia consisting of Very-Low Ti (VLT) basaltic clasts and a small component of highland-derived materials. The observed Pb-Pb age of phosphates in EET87521 is 3503 +/- 140 Ma, which is distinct from the results from p...