Early Carboniferous HP metamorphism in the Hida Gaien Belt,Japan: Implications for the Palaeozoic tectonic history of proto‐Japan     

Takumi Yoshida  Tomoki Taguchi  Hayato Ueda  Kenji Horie  M. Satish‐Kumar 《Journal of Metamorphic Geology》2021,39(1):77-100

We report two new eclogite localities (at Kanayamadani and Shinadani) in the high‐P (HP) metamorphic rocks of the Omi area in the western most region of Niigata Prefecture, Japan, which form part of the Hida Gaien Belt, and determine metamorphic conditions and pressure–temperature (P–T) paths. The metamorphic evolution of the eclogites is characterized by a tight hairpin‐shaped P–T path from prograde epidote–blueschist facies to peak eclogite facies and then retrograde blueschist facies. The prograde metamorphic stage is characterized by various amphibole (winchite, barroisite, glaucophane) inclusions in garnet, whereas the peak eclogite facies assemblage is characterized by omphacite, garnet, phengite and rutile. Peak P–T conditions of the eclogites were estimated to be ~600°C and up to 2.0 GPa by conventional cation‐exchange thermobarometry, Ti‐in‐zircon thermometry and quartz inclusion Raman barometry respectively. However, the Raman spectra of carbonaceous material thermometry of metapelites associated with the eclogites gave lower peak temperatures, possibly due to metamorphism at different conditions before being brought together during exhumation. The blueschist facies overprint following the peak of metamorphism is recognized by the abundance of glaucophane in the matrix. Zircon grains in blueschist facies metasedimentary samples from two localities adjacent to the eclogites have distinct oscillatory‐zoned cores and overgrowth rims. Laser ablation inductively coupled plasma mass spectrometry U–Pb ages of the detrital cores yield a wide range between 3,200 and 400 Ma, with a peak at 600–400 Ma. In the early Palaeozoic, proto‐Japan was located along the continental margin of the South China craton, providing the source of the older population of detrital zircon grains (3,200–600 Ma) deposited in the trench‐fill sediments. In addition, subduction‐related magmatism c. 500–400 Ma is recorded in the crust below proto‐Japan, which might have been the source for the younger detrital zircon grains. The peak metamorphic age was constrained by SHRIMP dating of the overgrowth rims, yielding Tournaisian ages of 347 ± 4 Ma, suggesting subduction in the early Carboniferous. Our results provide clear constraints on the initiation of subduction, accretion and the development of an arc‐trench system along the active continental margin of the South China craton and help to unravel the Palaeozoic tectonic history of proto‐Japan.  相似文献   

Orientation of X-Ray Bright Points in the Quiet Sun     

K. Ueda  R. Kano  S. Tsuneta  H. Shibahashi 《Solar physics》2010,261(1):77-85

Thanks to the high-resolution images from the X-ray telescope (XRT) aboard the Hinode satellite, X-ray bright points (XBPs) in the quiet region of the Sun are resolved and can be seen to have complex loop-like structures. We measure the orientation of such loop structures for 488 XBPs picked up in 26 snapshot X-ray images near the disk center. The distribution of the orientation is slightly but clearly biased to the east – west direction: the random distribution is rejected with a significance level of 1% by the χ ²-test. The distribution is similar to the orientation distribution for the bipolar magnetic fields. The XBP orientation is, however, much more random than that of the bipolar magnetic fields with similar size. 24% of the XBPs are due to emerging bipoles, while the remaining 76% are due to chance encounters of opposite polarities.  相似文献   

Meteorological influences of SST anomaly over the East Asian marginal sea on subpolar and polar regions: A case of an extratropical cyclone on 5–8 November 2006     

Ami Ueda  Masaru Yamamoto  Naoki Hirose 《Polar Science》2011,5(1):1-10

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An observational study of the structure of the nocturnal urban boundary layer   总被引：2，自引：0，他引：2  

I. Uno  S. Wakamatsu  H. Ueda  A. Nakamura 《Boundary-Layer Meteorology》1988,45(1-2):59-82

The formation mechanism of the nocturnal urban boundary layer (UBL), especially in the winter nighttime, was investigated based on the extensive field observations conducted during November 1984 in Sapporo, Japan. A strong, elevated inversion formed over the Sapporo urban area and the inversion base height was approximately twice the average building height. Velocity fluctuations _u, _w and Reynolds stress % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG1bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaam4DamaaCaaa% leqabaGaaGymaaaaaaaaaa!3A9C!\[\overline {u^1 w^1 } \] had nearly uniform profiles within the nocturnal UBL and decreased with height above the UBL. On the other hand, temperature fluctuations _t , and heat fluxes % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG1bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaeqiUde3aaWba% aSqabeaacaaIXaaaaaaaaaa!3B56!\[\overline {u^1 \theta ^1 } \] and % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG3bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaeqiUde3aaWba% aSqabeaacaaIXaaaaaaaaaa!3B58!\[\overline {w^1 \theta ^1 } \] had peaks at the inversion base and small values within the nocturnal UBL. The turbulent kinetic energy budget showed that the turbulent transport term and shear generation from urban canopy elements are important in the nocturnal UBL development; the role of the buoyancy term is small. The turbulence data analysis and application of a simple advective model showed that the mechanism of UBL formation may be controlled by the downward transport of sensible heat from the elevated inversion caused by mechanically-generated turbulence.Nomenclature g accelaration due to gravity, m s^-2 - k turbulent kinetic energy, m² s^-1 - K _m eddy viscosity, m² s^-1 - L Monin-Obukhov lenght, m - p pressure, Kg m^-2 - U, V, W mean wind speed in the downwind, crosswind, and vertical directions, respectively, m s^-1 - u ¹, w ¹ wind speed fluctuation in the downwind and vertical direction, respectively, m s^-1 - u ₁ friction velocity, m s^-1 - % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG1bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaam4DamaaCaaa% leqabaGaaGymaaaaaaaaaa!3A9C!\[\overline {u^1 w^1 } \] momentum flux, m²s^-2 - % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG1bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaam4DamaaCaaa% leqabaGaaGymaaaaaaaaaa!3A9C!\[\overline {u^1 \theta^1 } \] sensible heat flux, m²s^-1°C - WD wind direction, deg - WS wind speed, m s^-1 - z altitude, m - Z _h inversion base height, m - Z _j wind maximum height, m - Z _t inversion top height, m - T _u-r heat island intensity, °C - temperature lapse rate at rural site, °C m^-1 - energy dissipation rate, m²s^-3 - ¹ Potential temperature fluctuation, °C - _* scaling temperature, (=-% MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% WG1bWaaWbaaSqabeaacaaIXaaaaGGaaOGae8hiaaIaeqiUde3aaWba% aSqabeaacaaIXaaaaaaaaaa!3B56!\[\overline {u^1 \theta ^1 } \]/u_*) °C - mean potential temperature fluctuation, K - density of air, Kgm^-3 - K von Kármán constant (=0.4) - _u, _v, _w standard deviation of wind speed in the downwind, crosswind, and vertical directions, respectively, m s^-1 - standard diviation of temperature, °C  相似文献   

Supermassive black hole mass functions at intermediate redshifts from spheroid and AGN luminosity functions     

Naoyuki Tamura  Kouji Ohta  Yoshihiro Ueda 《Monthly notices of the Royal Astronomical Society》2006,365(1):134-146

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Dilatancy of granular materials in a strain space multiple mechanism model     

Susumu Iai  Tetsuo Tobita  Osamu Ozutsumi  Kyohei Ueda 《国际地质力学数值与分析法杂志》2011,35(3):360-392

A granular material consists of an assemblage of particles with contacts newly formed or disappeared, changing the micromechanical structures during macroscopic deformation. These structures are idealized through a strain space multiple mechanism model as a twofold structure consisting of a multitude of virtual two‐dimensional mechanisms, each of which consists of a multitude of virtual simple shear mechanisms of one‐dimensional nature. In particular, a second‐order fabric tensor describes direct macroscopic stress–strain relationship, and a fourth‐order fabric tensor describes incremental relationship. In this framework of modeling, the mechanism of interlocking defined as the energy less component of macroscopic strain provides an appropriate bridge between micromechanical and macroscopic dilative component of dilatancy. Another bridge for contractive component of dilatancy is provided through an obvious hypothesis on micromechanical counterparts being associated with virtual simple shear strain. It is also postulated that the dilatancy along the stress path beyond a line slightly above the phase transformation line is only due to the mechanism of interlocking and increment in dilatancy due to this interlocking eventually vanishing for a large shear strain. These classic postulates form the basis for formulating the dilatancy in the strain space multiple mechanism model. The performance of the proposed model is demonstrated through simulation of undrained behavior of sand under monotonic and cyclic loading. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

A Compact High-Voltage Pulse Generator for Plasma Applications     

V.A. Spassov  J. Barroso  M. Ueda  L. Guerguiev 《Astrophysics and Space Science》1997,256(1-2):533-538

The design and construction of a compact high-voltage pulse generator for providing input electron beam power for the LAP/INPE 32 GHz gyrotron and for treatment of metal and polymer materials by plasma immersion ion implantation (PIII) are described. The generator was built on a circuit category of Pulse Forming Network (PFN), consisting of nine LC sections with L = 270 H and C = 2.5 nF.The instrument was designed to produce a flat 30 kV, several Amps pulse in 15 s pulse length with pulse repetition frequency (PRF) of 8 to 100 Hz. By means of a resonant charging inductance it is possible to gain an output voltage with a factor of 1.8 higher than the voltage supplied by the pulse generator. The generator is fed with sine-wave, constant current source, and a 60 kV, 15 mA switching power supply.  相似文献   

Free-air anomalies in the western Pacific from the viewpoint of wave number spectrum     

Hiromi Fujimoto  Yoshibumi Tomoda  Hayato Shoji 《Marine Geophysical Researches》1984,7(1-2):209-214

Free-air anomalies in the western Pacific consist of the two groups of wavelengths 200–500 km and longer than 1,000 km. This is the reason why the patterns of short wavelength geoidal undulation and those of free-air anomalies in the western Pacific look alike with earch other. The gravity anomalies of shorter wavelengths can be explained by tectonics related with thickness of the lithosphere. Positive free-air anomalies of longer wavelengths may be explained by relics of the subsided lithosphere.  相似文献   

Contents of strontinm-90 and ruthenium-106 in beach and shallow water deposits of noto peninsula     

Yoshikazu Yamamoto  Kikuo Takeda  Shunzo Ueda 《Journal of Oceanography》1976,32(2):83-88

⁹⁰Sr,¹⁰⁶Ru, natural strontium and major elements were studied in 12 samples of beach deposits from Togi, Fukuura and Shiga, and in 26 samples of shallow water sediments from sea off Fukuura, Noto Peninsula, Ishikawa Pref., Japan.The average contents of natural strontium and⁹⁰Sr in the beach deposits were 488 ppm ranging from 247 to 1,550 ppm and 45±9 pCi kg^–1-dry mud ranging from 18 to 72 pCi kg^–1-dry mud, respectively. While the average contents of natural strontium,⁹⁰Sr and¹⁰⁶Ru in the sediments were 234 ppm ranging from 136 to 415 ppm, 22±6 pCi kg^–1-dry sand ranging from 7 to 48 pCi kg^–1-dry sand and 0.6 ±0.2 nCi kg^–1-dry ranging from 0.3 to 1.2 nCi kg^–1-dry, respectively.The average contents of each natural strontium and⁹⁰Sr in the beach deposits were about two times higher than those in the shallow water sediments. But no obvious relation of natural strontium to⁹⁰Sr was found in all the samples. The enrichment of⁹⁰Sr and¹⁰⁸Ru in the beach deposits or tthe sediments were as high as 150320 and of 2,0003,000 compared with average contents of⁹⁰Sr and¹⁰⁶Ru in a liter of surface water from the Japan Sea. It is to be noticed that the average¹⁰⁶Ru to⁹⁰Sr ratio of 27 for the shallow water sediments is much higher than the average of 1.0 for surface sea water of the Japan Sea.As to major elements of the samples, the beach deposits are rich in silicon (Av. 70.89 ±0.92% SiO₂), but poor in iron (Av. 2.99±0.32% Fe₂O₃). Whereas the shallow water sediments are poor in silicon (Av. 52.96±10.33% SiO₂) and rich in iron (Av. 5.50±1.90% Fe₂O₃), calcium (Av. 9.64±9.22% CaO) and magnesium (Av. 2.83±1.58% MgO).  相似文献   

Magma intrusion and discharge process at the initial stage of the 2000 activity of Miyakejima, Central Japan, inferred from tilt and GPS data   总被引：2，自引：0，他引：2  

Hideki Ueda  Eisuke Fujita  Motoo Ukawa  Eiji Yamamoto  Meilano Irwan  Fumiaki Kimata 《Geophysical Journal International》2005,161(3):891-906

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