Low‐temperature thermochronological database of bedrock in the Japanese Islands     

Shigeru Sueoka  Takahiro Tagami 《Island Arc》2019,28(4)

To provide better access to thermochronological data and understand the long‐term denudation history of the Japanese Islands, we compiled a low‐temperature thermochronological dataset of fission‐track (FT) and (U–Th–Sm)/He (He) ages for apatite and zircon in bedrocks. These thermochronometric ages are compiled from 90 literature sources and 1,096 localities, and include 418 apatite FT ages, 851 zircon FT ages, 42 apatite He ages, and 30 zircon He ages. Many FT ages have been reported previously; however, the number of He ages is limited in the Japanese Islands. The compiled data are spatially biased; for instance, more data are reported for the Chubu and Kinki districts and the Pacific coast of the Shikoku Island, whereas less data were available for the Tohoku and Chugoku districts. For better understanding arc‐scale uplift‐denudation history, further thermochronological research in the lesser‐studied regions and more He thermochronometric measurements are desired. This compilation will be updated and provided on the website of the Fission‐Track Research Group in Japan ( http://ftrgj.org/index.html ).  相似文献   

A tribute to Ei Horikoshi (1932–2009)     

Masaaki Shimizu  Shigeru Otoh  Nigel J. Cook 《Resource Geology》2012,62(4):327-328

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Is there any seasonal variation in marine nematodes within the sediments of the intertidal zone?     

Yodnarasri S  Montani S  Tada K  Shibanuma S  Yamada T 《Marine pollution bulletin》2008,57(1-5):149-154

The sediment parameters and nematode assemblages in the intertidal zone of the Hichirippu shallow lagoon, Hokkaido, Japan, were investigated. The objectives of this study were to observe the seasonal variation in the nematodes in the sediment, and to investigate the relationships between the nematodes and environmental factors. Samples were collected bi-monthly from five stations on the tidal flat from April 2003 to February 2004. It was found that the sediment parameters (Chl a concentration, AVS, TOC and TN contents) varied throughout the 10-month study. Fifty-four species of nematodes were found in the study area. The density and biomass of the nematodes varied in accordance with the sediment temperature during the sampling period. In this study, there was a seasonal variation in the nematode assemblage found in the intertidal zone of this shallow lagoon. The important factors affecting this variation were sediment temperature, and food competition among the nematodes themselves. The seasonal variation of the nematode also showed a relationship with the Chl a concentration in the sediment during the sampling period.  相似文献   

Determination of Platinum and Palladium in Sixty-Eight Geochemical Reference Samples by Flameless Atomic Absorption Spectrometry     

Shigeru TERASHIMA 《Geostandards and Geoanalytical Research》1991,15(1):125-128

Platinum and palladium contents of sixty-eight geochemical reference samples have been determined by graphite furnace atomic absorption spectrometry after digestion of sample with aqua regia and hydrofluoric acid and extraction of platinum and palladium as iodides by methylisobutylketone (MIBK). The data are compared with those from other studies and crustal abundances.  相似文献   

A strong motion database for the chiba seismometer array and its engineering analysis     

Tsuneo Katayama  Fumio Yamazaki  Shigeru Nagata  Lin Lu  Turgay Turker 《地震工程与结构动力学》1990,19(8):1089-1106

A three-dimensional seismometer array was installed in the Chiba Experiment Station of the Institute of Industrial Science, University of Tokyo in 1982. The array system consists of 44 three-component accelerometers densely placed both on the ground surface and in boreholes. A complementary system for the measurement of ground and buried pipe strains was also installed at the same site. The array system has been successfully in operation, and more than 160 earthquakes have been recorded. Considering a wide use of these seismograms, the Chiba array database has recently been created comprising twenty-seven major events. This paper describes the Chiba array system and its strong motion database. Results of engineering analysis using the selected records are also presented.  相似文献   

Numerical study for specifying the major origin of low salinity water associated with <Emphasis Type="Italic">Chattonella</Emphasis> (Raphidophyceae) blooms in Tachibana Bay,Japan     

Kazuhiro?AokiEmail author  Manabu?Shimizu  Hiroshi?Kuroda  Toshifumi?Yamatogi  Naoya?Ishida  Shigeru?Kitahara  Keiji?Hirano 《Journal of Oceanography》2016,72(5):811-816

In both 2009 and 2010, massive Chattonella blooms occurred in Tachibana Bay. Observation results show that high cell densities of Chattonella were distributed in the central area of Tachibana Bay with low salinity water. Model results indicate that the low salinity water originated from the Ariake Sea and intruded into Tachibana Bay during the northerly or weak winds. It is suggested that low salinity water was mainly discharged from the northern area of the Ariake Sea. Northerly wind enhanced the horizontal advection of the low salinity water intruding into Tachibana Bay originating from the northern area of the Ariake Sea.  相似文献   

Purine and pyrimidine bases in marine particles in the Seto Inland Sea, Japan     

Shigeru Montani  Kuninao Tada  Tomotoshi Okaichi 《Marine Chemistry》1988,25(4)

Purine and pyrimidine bases in marine environmental particles collected in Harima-Nada, the Seto Inland Sea, Japan, were investigated by high performance liquid chromatography.Purines and pyrimidines concentrations varied from 0.3 to 9.3 μg l⁻¹ (n=20) for suspended matter, and 0.3 to 0.6 mg g⁻¹ (n=10) for sinking particles. A good correlation was found between chlorophyll a and purine+pyrimidine bases in suspended matter, indicating that these bases contained in suspended matter originated from phytoplankton.A comparison between several compositional data of the suspended matter and the sinking particles, namely CN ratio, composition of purines and pyrimidines, and percentages of the nitrogen bases relative to total particulate organic nitrogen, demonstrates that the sinking particles were different from suspended matter. Also, from the variety of purine and pyrimidine concentrations of marine particle samples, it was estimated that the decomposition rate of these bases seemed more rapid than decomposition rates of amino acids reported in our earlier study.  相似文献   

The Rayleigh-Taylor instability in a self-gravitating two-layer fluid sphere     

Shigeru Ida  Yoshitsugu Nakagawa  Kiyoshi akazawa 《Earth, Moon, and Planets》1989,44(2):149-174

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Sunlight and tidal interaction as a mechanism of carbon transport in an ice-covered region: Results of a coupled ice–ocean ecosystem model     

Yoshiki Nishi  Shigeru Tabeta 《Continental Shelf Research》2007

In order to clarify the mechanism of carbon transport in an ice-covered ecosystem in Lake Saroma (44^°N${44}^{°}\mathrm{N}$, 143^°E${143}^{°}\mathrm{E}$, Hokkaido, Japan), a three-dimensional numerical calculation using a coupled ice–ocean ecosystem model was conducted. This model comprises an ocean ecosystem model, an ice ecosystem model, and equations for the coupling between ice and ocean. Comparisons of calculated results with observational data confirm that the calculation well reproduced the in situ phenomena with respect to tides, tidal currents, concentrations of POC and chlorophyll a in ice and in water, and sinking fluxes beneath the ice. The analysis of the organic carbon budget based on the calculation reveals that tide-induced transport, the enhancement of biological production in a pelagic system, and the physical release of organic matter from ice associated with ice-melting are important factors affecting the carbon transport during the ice-melting season. The carbon transport has a one-day time cycle. This is because principal driving forces are sunlight, and diurnal tides. The described mechanism of “sunlight and tidal pumping” is one of the most important features of carbon transport in a coupled ice–water ecosystem.  相似文献   

Determination of Total Sulfur in Thirty One Geochemical Reference Materials Using an Inductively Coupled Plasma-Atomic Emission Spectrometer Fitted with a Semiconductor Photodiode Detector   总被引：2，自引：0，他引：2  

Takashi Okai  Shigeru Terashima  Noboru Imai 《Geostandards and Geoanalytical Research》2001,25(1):133-136

The total sulfur contents of thirty one geochemical reference materials were determined using an inductively coupled plasma-atomic emission spectrometer fitted with a semiconductor photodiode detector. Most samples were decomposed using an HF-aqua regia digestion. However, a few were incompletely decomposed by simple acid digestion, and these were decomposed by a fusion method. The agreement between the analytical results from this work and published data is generally good.  相似文献