理学ZSX系列X荧光光谱仪中文软件开发   总被引：3，自引：1，他引：3  

邓赛文  片冈由行 《岩矿测试》2001,20(3):226-233

介绍了日本理学ZSX系列X荧光光谱仪的特点和新开发的中文版软件的功能。  相似文献   

Tectonic setting of high-Mg andesite magmatism in the SW Japan arc: K–Ar chronology of the Setouchi volcanic belt     

Yoshiyuki Tatsumi  Naoto Ishikawa  Ken Anno  Kyoichi Ishizaka  Tetsumaru Itaya 《Geophysical Journal International》2001,144(3):625-631

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Helium and carbon isotopes in fluorites: implications for mantle carbon contribution in an ancient subduction zone   总被引：1，自引：0，他引：1  

Junji Yamamoto  Makoto Watanabe  Yoshiyuki Nozaki  Yuji Sano   《Journal of Volcanology and Geothermal Research》2001,107(1-3)

The concentrations of helium and carbon in fluorite associated with Cretaceous to Neogene (90–13 Ma) granitic magmatism in the Japanese arc have been measured. Concentrations of Li, U, Th and Gd were measured to correct for secondary generated ³He. The CO₂/³He of fluorites are almost uniform (1.5×10¹⁰–4×10¹⁰) and in fair agreement with the range of present island arc volcanic gases. The calculated mantle C contribution in the Mesozoic subduction zone appear to have been identical to the present one (7–19%) indicating that the C flux from the mantle in supra-subduction zone environments has remained fairly constant during the past 70 million years.  相似文献   

Rapid and frequent turbidite accumulation in the bottom of Izu-Ogasawara Trench: Chemical and radiochemical evidence   总被引：1，自引：0，他引：1  

Yoshiyuki Nozaki  Yoichi Ohta 《Earth and Planetary Science Letters》1993,120(3-4):345-360

Two sediment cores (pilot gravity and piston) were obtained from the bottom of the Izu-Ogasawara Trench at 9750 m and analyzed for various elements and radioisotopes. The results showed a history of complex and frequent turbidite deposition: In the gravity core, eight layers rich in manganese were observed, of which five are enriched in Cu and Co as well. The other three are also enriched in Mo but no other heavy metals, suggesting the presence of at least two mechanisms of formation. Trapping of iron manganese micronodules can account for the enrichment of Mn, Cu and Co. The other three layers rich in Mn and Mo appear to be formed by a post-depositional diagenetic process of Mn mobilization and redeposition in the sediment column. A strong correlation between ²²⁶Ra and Cu in the gravity core suggests that the ²²⁶Ra was also carried into the bottom of the trench in turbidites in association with Mn micronodules. Little excess of ²¹⁰Pb over ²²⁶Ra was found at the top but the excess was significant at mid-depths from 30 to 70 cm, indicating that those sediments were deposited within the last 200 y.

In the piston core there is a sharp discontinuity of chemical and radiochemical composition around a depth of 250 cm. Below that depth the sediments appear to be dominated by materials derived from terrestrial sources, as compared with those in the upper layer which are of contemporary marine origin. ²²⁶Ra is deficient relative to ²³⁰Th throughout the sediment column down to 6 m. This finding is consistent with the finding that the average rate of sediment accumulation is 1–2 orders of magnitude faster than that in the western North Pacific abyssal plain, suggesting the convergence of materials into the bottom of the trench.  相似文献   

Magnesian andesite and basalt from Shodo-Shima Island,southwest Japan,and their bearing on the genesis of calc-alkaline andesites     

Yoshiyuki Tatsumi  Kyoichi Ishizaka 《Lithos》1982,15(2):161-172

Calc-alkaline andesites and olivine tholeiitic basalts are widely distributed on Shodo-Shima island, southwest Japan. The Fo content of olivine phenocrysts in the andesite is higher than in the basalt. The primary magma of the andesite, estimated on the basis of the olivine fractional crystallization model, is not basaltic but andesitic. The basalt contains both chromite and titanomagnetite as inclusions in olivine phenocrysts, while only chromite appears in the andesite. The Cr content of chromite in the andesite is higher than in the basalt. These facts again indicate that the andesite cannot be a fractionation product of the basalt, and that andesitic and basaltic primary magmas were generated independently.  相似文献   

High precision slip distribution of the 1944 Tonankai earthquake inferred from tsunami waveforms: Possible slip on a splay fault     

Toshitaka Baba  Phil R. Cummins  Takane Hori  Yoshiyuki Kaneda 《Tectonophysics》2006,426(1-2):119

Inversion of tsunami waveforms is a well-established technique for estimating the slip distributions of subduction zone earthquakes, with some of the most detailed results having been obtained for earthquakes in the Nankai Trough, SW Japan. The present study, although it uses a method and tsunami waveform data set almost identical to previous study, aims to improve on previous work by using a more precise specification of initial conditions for the calculation of tsunami Green's functions. Specifically, we incorporated four improvements in the present study: (1) we used a realistic plate model based only on seismic survey results, and assumed it to be the fault plane of the 1944 Tonankai earthquake; (2) the smallest subfaults consistent with the long wavelength approximation were used in the tsunami inversion analysis; (3) we included the effect of horizontal displacement of the ocean bottom on tsunami generation; and (4) we performed a checkerboard resolution test. As obtained in previous studies, a zone of high slip (> 2.0 m) was resolved off the Shima Peninsula. However, the more precise calculation of tsunami Green's functions has revealed additional detail that was not evident in previous studies, which we demonstrate is resolvable and correlates with the position of known faults in the accretionary prism. While there was little or no slip near the trench axis in the eastern part of the rupture zone, there was up to 1.5 m of slip resolved within 30 km of the trough axis in the western part, along the coast of the Kii Peninsula. This troughward slip zone coincides with the position of a large splay fault mapped in multichannel reflection surveys. Furthermore, it is also clear that the upper edge of the Enshu fault off Shima and Atsumi peninsulas is consistent with the up-dip limit of slip in the eastern part of our model. We tested the possibility that slip occurred on the former splay fault instead of on the plate interface during the 1944 Tonankai earthquake, and find that slip on this splay fault is also consistent with the data, although we cannot distinguish whether slip was dominant on the splay fault or on the plate interface. We further suggest that the position of the Enshu fault may be determined by the subduction of topographic highs, and that such faults may have an important influence on the up-dip rupture limit of the 1944 Tonankai and, potentially, other subduction zone earthquakes.  相似文献   

Non-destructive alpha-spectrometry and radiochemical studies of deep-sea manganese nodules     

Yoshiyuki Nozaki  Han-Soeb Yang 《Geochimica et cosmochimica acta》1985,49(8):1765-1774

A deep-sea Mn nodule handpicked from top of a 20 cm diameter North Pacific tripod core was directly counted by an α-spectrometer with a silicon surface barrier detector. A distinct ²¹⁰Po peak was recorded for the nodule upper side in contact with bottom seawater. Based on the spectrum, the ²¹⁰Po (supported by ²¹⁰Pb with 22 year half life) is thought to be confined in the top few microns of the nodule. Since the ²¹⁰Po peak diminishes considerably for the bottom side resting on sediment, nondestructive α-spectrometry is useful for determining the sea floor orientation of nodules. This method was tested for a western North Pacific dredged Mn nodule, and was successful in identifying the orientation (and also surface loss of the nodule by dredging).Radiochemical analysis was also carried out for carefully scraped samples from the top and bottom of the two nodules. The growth rates of the hand-picked nodule based on excess ²³⁰Th and ²³¹Pa profiles were 1 to 4 mm/10⁶ y and apparently varied with time. The dredged sample has grown at 2 to 6 mm/ 10⁶ y and the growth has likely been episodic. The radionuclide composition was significantly different between the top and bottom. Evidence was found that the radionuclide fluxes of ²³⁰Th and ²³¹Pa into the nodules considerably changed during the growing histories. The ²³⁰Th/²³²Th activity ratios in the nodule tops are comparable with those in bottom seawater suggesting that the top is growing with metals of seawater origin. However it remains unresolved whether the nodule bottoms are growing by utilizing metals in the sediment pore water.  相似文献   

Aeromagnetic surveys in the seas around Japan in 1980     

S. Utashiro  S. Oshima  T. Kaneko 《Surveys in Geophysics》1984,6(3-4):271-290

Aeromagnetic surveys in the seas around Japan were carried out in 1979 to 1980 by a YS-11 aircraft of the Maritime Safety Agency of Japan using a new type of airborne magnetometer system. The new type of airborne magnetometer system consists of a ring-core type three-component fluxgate magnetometer, an inertial sensing system, a fish-eye camera to measure the true north, an 8-bit microcomputer and a proton magnetometer. The VLF/OMEGA system is used to fix the position of the aircraft. Tracks extended to about 600 nautical miles off the coast of the Japanese islands in the Sea of Japan and the North-West Pacific Ocean. Average spacing between tracks was about 80 miles. The flights were carried out at an altitude of 9500 feet. From the survey results, magnetic charts of the seven geomagnetic elements for 1980 over the sea around Japan were compiled by the method of least squares using a polynomial. Also, the contour charts of secular variation in 1980 were compiled.  相似文献   

Recalibration of mutually consistent garnet–biotite and garnet–cordierite geothermometers     

Yasunari Kaneko  Takashi Miyano 《Lithos》2004,73(3-4):255-269

Garnet–biotite and garnet–cordierite geothermometers have been consistently calibrated, using the results of Fe²⁺–Mg cation exchange experiments and utilizing recently evaluated nonideal mixing properties of garnet. Nonideal mixing parameters of biotite (including Fe, Mg, Al^VI, and Ti) and of cordierite (involving Fe and Mg) are evaluated in terms of iterative multiple least-square regressions of the experimental results. Assuming the presence of ferric Fe in biotite in relation to the coexisting Fe-oxide phases (Case A), and assuming the absence of ferric Fe in biotite (Case B), two formulae of garnet–biotite thermometer have been derived. The garnet–cordierite geothermometer was constructed using Margules parameters of garnet adopted in the garnet–biotite geothermometers. The newly calibrated garnet–biotite and garnet–cordierite thermometers clearly show improved conformity in the calculated temperatures. The thermometers give temperatures that are consistent with each other using natural garnet–biotite–cordierite assemblages within ±50 °C. The effects of ferric Fe in biotite on garnet–biotite thermometry have been evaluated comparing the two calibrations of the thermometer. The effects are significant; it is clarified that taking ferric Fe content in biotite into account leads to less dispersion of thermometric results.  相似文献   

Multi-resolution clustering analysis and 3-D visualization of multitudinous synthetic earthquakes     

Witold Dzwinel  David Yuen  Yoshihiro Kaneko  Krzysztof Boryczko  Yehuda Ben-Zion 《Visual Geosciences》2003,8(1):1-32

We use modern and novel techniques to study the problems associated with detection and analysis of multitudinous seismic events, which form the background for isolated great earthquakes. This new approach involves multivariate analysis of low and large magnitude events recorded in space over a couple of centuries in time. We propose here the deployment of the clustering scheme both for extracting small local structures and large-scale trends in synthetic data obtained from four numerically simulated models with: uniform properties (U), a Parkfield-type asperity (A), fractal brittle properties (F), and multi-size-heterogeneity fault zone (M). The mutual nearest neighbor (mnn) clustering scheme allows for extraction of multi-resolutional seismic anomalies in both the spatio-temporal and multi-dimensional feature space. We demonstrate that the large earthquakes are correlated with a certain pathway of smaller events. Visualization of the anomalies by using a recently introduced visualization package Amira reveals clearly the spatio-temporal relationships between clusters of small, medium and large earthquakes, indicating significant stress relaxation across the entire fault region. We demonstrate that this mnn scheme can extract distinct clusters of the smallest events, which precede and follow a singularly large magnitude earthquake. These clusters form larger spatio-temporal structures comprising a series of large earthquakes. The link between the large and medium magnitude events is not so clearly understood. Short-ranged correlations are dominated by strong spatio-temporal anomalies, thus reflecting the global seismic properties of the entire fault zone.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.  相似文献