Active spreading and hydrothermalism in North Fiji Basin (SW Pacific). Results of Japanese French Cruise Kaiyo 87     

Jean-Marie Auzende  Eiichi Honza  Xavier Boespflug  Satendra Deo  Jean-Philippe Eissen  Jun Hashimoto  Philippe Huchon  Junichiro Ishibashi  Yo Iwabuchi  Philip Jarvis  Masato Joshima  Kiyoyuki Kisimoto  Yasuto Kuwahara  Yves Lafoy  Tsuyoshi Matsumoto  Jean-Pierre Maze  Kiyohiko Mitsuzawa  Hiroyasu Monma  Takeshi Naganuma  Yukihiro Nojiri  Suguru Ohta  Kiyoshi Otsuka  Yoshihisa Okuda  Hélène Ondreas  Akira Otsuki  Etienne Ruellan  Myriam Sibuet  Manabu Tanahashi  Takeo Tanaka  Tetsuro Urabe 《Marine Geophysical Researches》1990,12(4):269-283

The aim of the Japanese-French Kaiyo 87 cruise was the study of the spreading axis in the North Fiji Basin (SW Pacific). A Seabeam and geophysical survey allowed us to define the detailed structure of the active NS spreading axis between 16° and 22° S and its relationships with the left lateral motion of the North Fiji Fracture Zone. Between 21° S and 18°10′ S, the spreading axis trends NS. From 18°10 S to 16°40 S the orientation of the spreading axis changes from NS to 015°. North of 16°40′ S the spreading axis trends 160°. These two 015° and 160° branches converge with the left lateral North Fiji fracture zone around 16°40′ S to define an RRFZ triple junction. Water sampling, dredging and photo TV deep towing give new information concerning the hydrothermal activity along the spreading axis. The discovery of hydrothermal deposits associated with living communities confirms this activity.  相似文献   

Fluoride contents of saline and interstitial waters in the inlets of the Juneau Glacier Area,Alaska     

Yasushi Kitano  Yukihiro Furukawa 《Journal of Oceanography》1972,28(4):176-179

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Geomorphological study on a clastic accretionary prism: The Nankai Trough     

Kyoko  Okino Yukihiro  Kato 《Island Arc》1995,4(3):182-198

Abstract The Nankai Trough, off southwest Japan, is one of the best sites for the study of geomorphic characteristics of a clastic accretionary prism. A recent multibeam survey over the central and eastern parts of the Nankai accretionary prism has revealed a large variation of the topography along the trough axis. Analysis of the bathymetric data suggests the existence of prism deformational features of different scales, such as depressions, embayment structures and cusps. These structures are the results of slope instability caused by basement relief of subducted oceanic plate. Unstable slopes recover by new accretion and development of a low angle thrust. Small-scale deformation due to the subduction of a small isolated seamount is then adjusted to the regional trend. By contrast, a 30 km indentation of the wedge observed in the eastern part of the Nankai Trough, the Tenryu Cusp, has seemed to retain its geometry. The subducted Philippine Sea plate has deformed greatly near the eastern end of the Nankai Trough, because of the collision between the Izu-Ogasawara (Bonin) arc and central Japan. Therefore, the indentation may be the result of the continuous subduction of a basement high, such as the Zenisu Ridge, which has been formed under north-south compression due to the arc-arc collision.  相似文献   

A Simple Single-Layer Urban Canopy Model For Atmospheric Models: Comparison With Multi-Layer And Slab Models   总被引：26，自引：7，他引：26  

Hiroyuki Kusaka  Hiroaki Kondo  Yokihiro Kikegawa  Fujio Kimura 《Boundary-Layer Meteorology》2001,101(3):329-358

We developed a simple, single-layer urban canopy model, and comparedit to both multi-layer and slab models. Our single-layer model has thefollowing features: (a) It is a column model of energy and momentumexchange between an urban surface and the atmosphere, (b) it includesthe influence of street canyons, which are parameterized to representthe urban geometry, (c) it includes shadowing from buildings andreflection of radiation, and (d) it estimates both the surfacetemperatures of, and heat fluxes from, three surface types: roof, wall,and road. In the simulation of the single-layer model, the roof washottest during the daytime, but coolest from midnight to early morning.This is consistent with output from the multi-layer model and fieldobservations at a residential area on a clear, summer day. The diurnalvariation of the energy budget from the single-layer model agrees wellwith that from the multi-layer model. Our single-layer model'sperformance is nearly that of a multi-layer model for studyingmesoscale heat islands. Nevertheless, it is simply parameterized,and thus easily included in larger-scale atmospheric models. The slabmodel has the largest nighttime cooling rate of the three models. Toovercome this, it needs more adjustments than for the canopy models.  相似文献   

The use of sintered diamond anvils in the MA8 type high-pressure apparatus     

Tadashi Kondo  Hiroshi Sawamoto  Akira Yoneda  Manabu Kato  Akihito Matsumuro  Takehiko Yagi  Takumi Kikegawa 《Pure and Applied Geophysics》1993,141(2-4):601-611

A new multi-anvil type high-presure apparatus has been developed using sintered diamond anvils to generate pressures over 30 GPa and temperatures up to about 2000°C. A maximum sample volume of about 1 mm³ is available in this system. The pressure was confirmed by dissociation of forsterite into Mg-perovskite and periclase. The basic techniques and problems in utilizing sintered diamond in the MA8 type high-pressure apparatus are discussed with an emphasis on the future prospect of incorporating simultancous X-ray diffraction observation.  相似文献   

Corrigendum to “Climatological mean and decadal change in surface ocean pCO₂, and net sea–air CO₂ flux over the global oceans” [Deep Sea Res. II 56 (2009) 554–577]     

Taro Takahashi  Stewart C. Sutherland  Rik Wanninkhof  Colm Sweeney  Richard A. Feely  David W. Chipman  Burke Hales  Gernot Friederich  Francisco Chavez  Christopher Sabine  Andrew Watson  Dorothee C.E. Bakker  Ute Schuster  Nicolas Metzl  Hisayuki Yoshikawa-Inoue  Masao Ishii  Takashi Midorikawa  Yukihiro Nojiri  Arne Krtzinger  Tobias Steinhoff  Mario Hoppema  Jon Olafsson  Thorarinn S. Arnarson  Bronte Tilbrook  Truls Johannessen  Are Olsen  Richard Bellerby  C.S. Wong  Bruno Delille  N.R. Bates  Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076

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Geochemical and isotopic characteristics of the Cretaceous Orikabe Plutonic Complex,Kitakami Mountains,Japan: magmatic evolution in a zoned pluton and significance of a subduction-related mafic parental magma     

Masumi?Ujiie?MikoshibaEmail author  Satoshi?Kanisawa  Yukihiro?Matsuhisa  Shigeko?Togashi 《Contributions to Mineralogy and Petrology》2004,146(4):433-449

The Orikabe Plutonic Complex, northeast Japan, is a zoned pluton and one of the Cretaceous intrusions in the Circum-Pacific area. In the Main body, K-rich calc-alkaline rocks composed of marginal gabbro and a large amount of monzodiorite–quartz monzonite–monzogranite are intruded successively by innermost calc-alkaline rocks of granodiorite. The gabbro and monzodiorite–monzogranite have a continuous chemical variation, while the granodiorite has lower concentrations of K, Rb, Y, Zr, Nb and F at the same SiO₂ content. The gabbro and monzodiorite–quartz monzonite have a Rb-Sr whole-rock age of 119±12 Ma with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70392±0.00007. The initial ⁸⁷Sr/⁸⁶Sr ratio of the innermost granodiorite is estimated to be about 0.7042. The ¹⁸O values of fresh rocks range from +6.7 to +8.3, indicating a positive correlation with SiO₂ contents. The K-rich calc-alkaline rocks were derived through fractional crystallization from a mafic parental magma with a slightly high ¹⁸O value, implying a major contribution of a sub-arc mantle at a continental margin. Trace element modeling indicates that the source could have been a fertile lherzolite enriched in LILE and depleted in HFSE. The innermost granodiorite was the differentiation product of a distinct parental magma, suggesting the involvement of a small amount of crustal component in the source and partial melting under a more hydrous condition.Editorial responsibility: J. Hoefs  相似文献   

Compression behaviors of distorted rutile-type hydrous phases, MOOH (M?=?Ga, In, Cr) and CrOOD     

Asami Sano-Furukawa  Takehiko Yagi  Taku Okada  Hirotada Gotou  Takumi Kikegawa 《Physics and Chemistry of Minerals》2012,39(5):375-383

X-ray diffraction measurements of distorted rutile-type oxyhydroxides β-GaOOH, InOOH, β-CrOOH, and β-CrOOD were taken at a maximum pressure of up to 35 GPa under quasi-hydrostatic conditions, at ambient temperature. Anomalies in the evolution of the relative lattice constants and the axial ratios of β-GaOOH, InOOH, and β-CrOOD suggest anisotropic stiffening along the a- and/or b-axes where the hydrogen bond is formed. The changes were observed at 15 GPa in β-GaOOH and InOOH and at 4 GPa in β-CrOOD. The pressures were higher in oxyhydroxides that have longer O…O distances of the hydrogen bond at ambient pressure. In contrast, such stiffening behavior was not observed in CrOOH, which has a significant short O…O distance and strong hydrogen bond. The stiffening behaviors observed in the present study can be attributed to the symmetrization of the hydrogen bonds in oxyhydroxides, as was previously found in δ-AlOOH(D).  相似文献   

Pressure and temperature dependence of the viscosity of a NaAlSi<Subscript>2</Subscript>O<Subscript>6</Subscript> melt     

Akio Suzuki  Eiji Ohtani  Hidenori Terasaki  Keisuke Nishida  Hiromi Hayashi  Tatsuya Sakamaki  Yuki Shibazaki  Takumi Kikegawa 《Physics and Chemistry of Minerals》2011,38(1):59-64

The viscosity of a silicate melt of composition NaAlSi₂O₆ was measured at pressures from 1.6 to 5.5 GPa and at temperatures from 1,350 to 1,880°C. We employed in situ falling sphere viscometry using X-ray radiography. We found that the viscosity of the NaAlSi₂O₆ melt decreased with increasing pressure up to 2 GPa. The pressure dependence of viscosity is diminished above 2 GPa. By using the relationship between the logarithm of viscosity and the reciprocal temperature, the activation energies for viscous flow were calculated to be 3.7 ± 0.4 × 10² and 3.7 ± 0.5 × 10² kJ/mol at 2.2 and 2.9 GPa, respectively.  相似文献   

In situ observation of a garnet/perovskite transition in CaGeO<Subscript>3</Subscript>     

Shigeaki Ono  Takumi Kikegawa  Yuji Higo 《Physics and Chemistry of Minerals》2011,38(9):735-740

We used an in situ measurement method to investigate the phase transition of CaGeO₃ polymorphs under high pressures and temperatures. A multi-anvil high-pressure apparatus combined with intense synchrotron X-ray radiation was used. The transition boundary between a garnet and a perovskite phase at T = 900–1,650 K and P = 3–8 GPa was determined as occurring at P (GPa) = 9.0−0.0023 × T (K). The transition pressure determined in our study is in general agreement with that observed in previous high-pressure experiments. The slope, dP/dT, of the transition determined in our study is consistent with that calculated from calorimetry data.  相似文献