Structure and crystal chemistry of hydrous wadsleyite, Mg1.75SiH0.5O4: possible hydrous magnesium silicate in the mantle transition zone     

Y. Kudoh  T. Inoue  H. Arashi 《Physics and Chemistry of Minerals》1996,23(7):461-469

The crystal structure of hydrous wadsleyite, Mg_1.75SiH_0.5O₄ synthesized in an MA 8-type apparatus at conditions of 1300°C and 15.5 GPa, has been analyzed and refined in space group Imma, using the X-ray intensities measured on a 60X60X10 μm single crystal. The composition (Z=8) and unit cell are Mg_1.74Si_0.97H_0.65O₄ by E.P.M.A. analysis and a=5.663(1) Å, b= 11.546(2) Å, c=8.247(4) Å, V=539.2(5) ų. The partial M-site occupancies were determined; vacancies associated with the incorporation of water are strongly concentrated on the Mg 3 site. The OH in the structure was confirmed by Raman and FTIR spectroscopies. The result of valence sum calculation based on the refined bond lengths indicates that O1 is a hydroxyl. The formula of hydrous wadsleyite can be expressed as Mg_2-xSiH_2xO₄, where 0≤x≤0.25. When x=0.25, all of the O1 site is hydroxyl and the maximum solubility of 3.3 wt% H₂O is realized. Structural relations to other dense hydrous phases are discussed.  相似文献   

Sulfate reduction using methane in sediments beneath a bathyal “cold seep” giant clam community off Hatsushima Island, Sagami Bay, Japan     

Toshiyuki Masuzawa  Nobuhiko Handa  Hiroyuki Kitagawa  Minoru Kusakabe 《Earth and Planetary Science Letters》1992,110(1-4):39-50

Two sandy sediment cores (Cores D227-120 and D380) were collected from inside a deep-sea giant clam (Calyptogena soyoae) community off Hatsushima Island, western Sagami Bay, central Japan (35°59.9′N, 139°13.6′E; 1160 m deep) and a muddy sediment core (Core D227-202) was obtained from outside the community by the submersibleShinkai 2000. The chloride concentration of the pore waters is constant vertically and sulfate reduction using sedimentary organic matter occurs in Core D227-202 (21 cm long). The chloride concentrations are lower by 7% at the 7.5–9 cm depth in Core D227-120 (9 cm long) and by 3% at the 11–12 cm depth in Core D380 (16 cm long) than those of the overlying bottom waters in the cores from inside of the community. Sulfate concentration decreases remarkably and dissolved inorganic carbon, alkalinity, ammonium-N, and hydrogen sulfide concentrations increase significantly with increasing depth in Core D380.δ³⁴S values of sulfate ions increase from +20.5 to +35.3‰ andδ¹³C values of dissolved inorganic carbon decrease drastically from −7.0 to −45‰ with increasing depth from the top to the bottom of the core, although theδ¹³C values of the organic carbon of the sediments are−23.7 ± 0.9‰ in Core D380. These results indicate that sulfate reduction using methane is active within the sediments just beneath the living clams and that the hydrogen sulfide produced can be used by endosymbiotic sulfur oxidizing bacteria living in the gills ofC. soyoae in the community.  相似文献   

松嫩平原西部碱尘气溶胶的元素特征分析     

胡克  陈兵  介冬梅  赵奎涛 《吉林大学学报(地球科学版)》2006,36(3):417-423

碱尘暴期间松嫩平原西部碱尘气溶胶的主要元素质量浓度排序为Na、Al、Fe、Ca、Mg、K、Ti、Ba、Zn,与当地盐碱化土壤的元素组成吻合,而与沙尘、城市气溶胶的元素组成有差别。风力对碱尘气溶胶元素组成有明显的影响,当风速在8.0~17.1 m/s时,元素组成的质量浓度排序为Na、Ca、Al、Fe、Mg、K、Ba、Ti、Zn。Na元素质量浓度的激增是碱尘暴元素组分的一大特征,明显富集元素为Na和B;相对于当地背景大气气溶胶的富集情况,Zn、Cu、Ba、B的富集因子值在碱尘暴期间明显降低;在各种天气情况下,B、Cu均具有较高的富集因子。碱尘中Ti元素的富集因子值均小于1,而Ca、Fe、K、Mg、Mn、Sr、V的富集因子值为1~4。两个采样点的Ca、Na、Al、Fe、Mg、Ti、Zn的富集因子近似,表明该区碱尘的主要元素具有特定的一致性;而B、Ba、Cu、V的富集因子相差较大,可以作为区分不同碱尘源的标志性元素。  相似文献   

Performance of a lithium fluoride bolometer for Tokyo dark matter search experiment     

Wataru Ootani  Makoto Minowa  Takayuki Watanabe  Yutaka Ito  Yasuhiro Kishimoto  Kentaro Miuchi  Yoshizumi Inoue  Youiti Ootuka 《Astroparticle Physics》1998,9(4):325-329

The performance of a 21-g lithium fluoride bolometer is presented. The background spectrum was measured in the surface laboratory. We derive an exclusion plot for the spin-dependent coupled Weakly Interacting Massive Particles (WIMPs) cross section.  相似文献   

Excitation of secondary Love and Rayleigh waves in a three-dimensional sedimentary basin evaluated by the direct boundary element method with normal modes     

Ken Hatayama  & Hiroyuki Fujiwara 《Geophysical Journal International》1998,133(2):260-278

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¹⁰Be dating of North Pacific sediment cores up to 2.5 million years B.P.     

Shigeo Tanaka  Teruo Inoue 《Earth and Planetary Science Letters》1979,45(1):181-187

The¹⁰Be method of dating of marine sediment cores is applied to five North Pacific cores. Assuming a constant¹⁰Be precipitation rate and varying sedimentation rates with time during the past 2.5 m.y. dating confirms to that obtained from paleomagnetic stratigraphy. The¹⁰Be concentration variations with depth in the cores are primarily due to changes in sediment dilution and do not reflect cosmic ray intensity or global climate variations. The limits of¹⁰Be deposition rate variation in the investigated cores are less than ± 10% for periods of (2–7) × 10⁵ years and less than ±30% for periods of 1 × 10⁵ years. The data set gives a half-life of¹⁰Be is 1.50 × 10⁶ years. The latitudinal effect of¹⁰Be concentrations and¹⁰Be/⁹Be ratios relates to a frequency of particulate matter occurrence (detrital and biological particles) in the oceans and to oceanic circulation.  相似文献   

¹⁰Be in marine sediments     

Teruo Inoue  Shigeo Tanaka 《Earth and Planetary Science Letters》1976,29(1):155-160

The depth profile of the long-lived radionuclide¹⁰Be in a marine sediment recovered in the vicinity of the Samoan Islands has been precisely assayed with a highly sensitive needle-type gas counter. The obtained irregular pattern of¹⁰Be concentrations with depths ranging from 4.7 to 0.3 dpm/kg dry sediment is interpreted as being due to dilution of¹⁰Be by volcanic eruptions in the past.  相似文献   

Current activities in aerobiology in Japan     

Eiichi Inoue 《Boundary-Layer Meteorology》1974,7(3):257-266

A brief review of the research activities of Japanese scientists in aerobiology, which is one of the interdisciplinary sciences closely related to atmospheric turbulence and diffusion as well as to biology, is presented in order to make contacts with interested scientists in other countries.  相似文献   

Ultraviolet dust attenuation in spiral galaxies: the role of age-dependent extinction and the initial mass function     

P. Panuzzo  G. L. Granato  V. Buat  A. K. Inoue  L. Silva  J. Iglesias-Páramo  A. Bressan 《Monthly notices of the Royal Astronomical Society》2007,375(2):640-648

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Application of Chlorite Geothermometry to Hydrothermal Alteration in Toyoha Geothermal System, Southwestern Hokkaido, Japan   总被引：1，自引：0，他引：1  

Atsuyuki Inoue  Kyohei Kurokawa    Tamao Hatta 《Resource Geology》2010,60(1):52-70

In this study, we applied chemical geothermometers to the estimation of formation temperatures of chlorites from various types of hydrothermally altered rocks in the Toyoha geothermal field, using core samples from six drill holes (TH-2 to TH-7) together with wasted ore samples from Toyoha vein-type ore deposit. Based on the preliminary examination of mineral assemblages by X-ray powder diffraction and optical microscopy, hydrothermal alteration observed through the drill holes was classified into four types of alteration zones: propylitic, mixed-layer minerals, kaolin minerals, and ore mineralized zones. The mineral assemblage of the ore mineralized zone observed through TH-2, TH-4, and TH-6 is similar to those of Toyoha ore veins reported previously. The Fe³⁺/ΣFe ratios of chlorites were determined by X-ray photoelectron spectroscopy (XPS), in addition to the usual microprobe analyses. The ratios ranged from 0.20–0.26 for chlorites from the propylitic alteration zone and from 0.13 to 0.17 for those from the ore mineralized zone associated with sulfide minerals. After correcting the Fe³⁺ contents in the octahedral sites of chlorite structures, we obtained acceptable temperatures of the chlorite formation by application of geothermometers, for instance, a similar range of 150–300°C for chlorites from either the propylitic zone or the ore mineralized zone developed through TH-2, TH-4, and TH-6. Chlorites from the ore mineralized zone proximal to the Toyoha deposit are characterized by high Fe and Mn contents compared to the propylitic chlorites, which is similar to the Toyoha vein-filling chlorites; the formation temperatures were close to both the homogenization temperatures of fluid inclusions and the present subsurface temperatures measured through drill holes. Chlorites from the Toyoha ore veins, however, gave slightly higher formation temperatures (180–350°C) than those of chlorites from the ore mineralized zone in the drill cores. This suggests that several types of hydrothermal alteration occurred at different stages in the Toyoha geothermal field and the composition of product chlorite was controlled not only by the temperature but also the composition of fluid related to the formation. Reliable estimation of temperature for the chlorite formation provides basic information on evaluating correctly other physicochemical conditions prevalent at the formation.  相似文献