The influence of environmental variability on silicate exchange rates between sediment and water in a shallow-water coastal ecosystem,the Seto Inland Sea,Japan   总被引：2，自引：0，他引：2  

Srithongouthai S  Sonoyama Y  Tada K  Montani S 《Marine pollution bulletin》2003,47(1-6):10-17

Silicate regeneration was determined in a shallow-water coastal ecosystem (Shido Bay, the Seto Inland Sea, Japan) during 1999-2000. The present study was carried out directly by core incubation and by determining gradients of dissolved silicate (DSi) in the pore water. Incubated fluxes ranged from 25.5 to 132.6 mgSim(-2)d(-1), and were 1.6-21.6 times greater than diffusive fluxes (5.4-43.3 mgSim(-2)d(-1)). The disparity between fluxes measured by core incubation and modeling pore water indicated that other physical, chemical or biological processes, in addition to diffusion of DSi from below, contribute to DSi fluxes measured during the incubation of undisturbed cores. A regression analysis revealed that water temperature and salinity explained 24% and 23%, respectively, of season to season variability in incubated fluxes. Microphytobenthos was responsible for 37% of the variability in measured rate of DSi fluxes, with greatly reducing DSi release rates due to their own DSi demand. Moreover, the inverse relationship between the DSi fluxes and biogenic silica (Bio-Si) concentrations in the surface sediment, suggested that about 41% of the variability in the DSi fluxes were explained by Bio-Si concentrations in the surface sediment. As a result, Shido Bay showed silicate regeneration of incubated cores to be a consequence of Bio-Si dissolution depending on microphytobenthos, temperature and salinity, while diffusive fluxes appeared to be limited by DSi in the pore water. An annual average of DSi flux (68.7+/-32.9 mgSim(-2)d(-1)) from the sediments to the water column corresponds to 38% of DSi, required for primary production by phytoplankton in Shido Bay.  相似文献   

DATABASE ON INTERNET FOR GEOLOGICAL SURVEY OF JAPAN GEOCHEMICAL REFERENCE SAMPLES     

Noboru IMAI  Hiroshi SAKURAMACHI  Shigeru TERASHIMA  Shiro ITOH  Atsushi ANDO 《Geostandards and Geoanalytical Research》1996,20(2):161-164

A database on thirty-one Geological Survey of Japan (GSJ) geochemical reference samples has been set up on Internet which allows the retrieval of recommended or preferable values, compiled data, location, sample preparation and other relevant information. The URL location on WWW server is: http://www.aist.go.jp./RIODB/geostand/welcome.html  相似文献   

Determination of Indium and Tellurium in Fifty Nine Geological Reference Materials by Solvent Extraction and Graphite Furnace Atomic Absorption Spectrometry     

Shigeru Terashima 《Geostandards and Geoanalytical Research》2001,25(1):127-132

The indium (In) and tellurium (Te) contents of fifty nine geological reference materials, issued by several reference material producers (USGS, CRPG, ANRT, GIT-IWG and GSJ) have been determined by graphite furnace atomic absorption spectrometry, after aqua regia and HF digestion, and extraction of iodide complexes with trioctylmethylammonium (TOMA) - metyl isobutyl ketone (MIBK). Although the interferences from most elements can be minimised by the addition of palladium solution as the matrix modifier, large concentrations of Bi, Cu, Pb or Sn suppress the absorbance of In and/or Te. Samples for analysis were therefore restricted to those in which the concentrations of these interfering elements did not cause a significant interference. The limit of detection was 0.2 ng g⁻¹ In and Te for 1 g test portions. The agreement between the reported results and published data is satisfactory.  相似文献   

A NUMERICAL STUDY ON THE FORMATION AND DEVELOPMENT OF ISLAND-INDUCED CYCLONE AND ITS IMPACT ON TYPHOON STRUCTURE CHANGE AND MOTION   总被引：16，自引：0，他引：16  

Meng Zhiyong  Nagata Masashi  Chen Lianshou 《Acta Meteorologica Sinica》1996,10(4):430-443

In this paper,the impact of the Taiwan Island topography on the structure change and motion ofTyphoon Dot(9017)during its crossing the Taiwan Island is studied with a modified version of aJMA operational regional model(Japan spectral model,JSM).A series of sensitivity experiments areconducted to detect the forming and developing mechanism of an island-induced cyclone.Results showthat lee side low pressure center plays a very important role in the formation of the induced-cyclonewhile a typhoon is approaching a large island with high mountains.The position and intensity of theinduced cyclone is sensitive to the height and location of island mountain,intensity of TC and under-lying surface topography distribution as well.A preliminary formation criterion of the island-inducedcyclone is obtained.  相似文献   

GOLD IN TWENTY-SIX JAPANESE GEOCHEMICAL REFERENCE SAMPLES     

Shigeru TERASHIMA  Shiro ITOH  Atsushi ANDO 《Geostandards and Geoanalytical Research》1992,16(1):9-10

Gold has been determined in 26 geochemical reference samples with graphite furnace AAS after digesting the samples with aqua regia and hydrofluoric acid and extracting gold by methyl isobutyl ketone (MIBK). This method yields clearly higher values than those by the partial attack using aqua regia digestion.  相似文献   

Fluorite Deposits at Voznesenka in the Khanka Massif, Russia: Geology and Age of Mineralization   总被引：1，自引：0，他引：1  

Kohei Sato  Kazuhiro Suzuki  Munetomo Nedachi    Shigeru Terashima    Margarita D. Ryazantseva    Anatoly A. Vrublevsky  + Alexander I. Khanchuk  ++ 《Resource Geology》2003,53(3):193-211

Abstract. A huge fluorite deposit at Voznesenka in the Khanka massif, Far East Russia is concluded to have formed at ca. 450 Ma in Late Ordovician time based on the K‐Ar ages for Li‐micas in the fluorite ore and greisenized leucogranite within the deposit. This conclusion is inconsistent with the current view of Devonian mineralization that stemmed from widely scattered whole‐rock Rb‐Sr isotope data for the heterogeneous leucogranite stocks influenced by strong alteration. The Voznesenka and neighboring fluorite deposits may have formed in Cambrian limestone in relation to the intrusion of the Li‐F‐rich felsic magma which has a similar chemistry to representative Li‐F‐rich felsic rocks including topaz granite and ongonite or topaz rhyolite; these rocks may be classified as a specific group of highly fractionated felsic magmas. Biotite granite plutons exposed in the Voznesenka district are divided in age into two groups based on the CHIME age data for zircon, monazite and xenotime: Ordovician and Permian. The Ordovician plutons seem to be coeval to the fluorite deposits and are characterized by F‐rich chemistry, reduced nature and association of tin mineralization with the deposition of fluorite and tourmaline. The biotite granite magmas of initially enhanced F contents could have been highly fractionated to form Li‐F‐rich leucogranite cupolas that provided fluorite deposits within the host limestone. Future prospecting for similar fluorite deposits is to be focused on areas of intersection between Ordovician Li‐F‐rich granite and Cambrian carbonate sequences. The Permian granite of southeastern margin of the Grodekovo batholith is characterized by lesser F content, oxidized nature and the lack of tin and fluorite mineralization in contrast to the Ordovician granite. The result of Permian age does not support the current view of Silurian age for the batholith and requires overall chronological reinvestigation in connection with the tectonic history of the Khanka massif because the Grodekovo is a representative of Paleozoic batholiths in Primorie.  相似文献   

The Preparation and Preliminary Characterisation of Four New Geological Survey of Japan Geochemical Reference Materials: Soils, JSO-1 and JSO-2; and Marine Sediments, JMS-1 and JMS-2   总被引：1，自引：0，他引：1  

Shigeru Terashima  Noboru Imai  Masahiro Taniguchi  Takashi Okai  Akira Nishimura 《Geostandards and Geoanalytical Research》2002,26(1):85-94

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Determination of Molybdenum in Fifty Three Geochemical Reference Materials by Flameless Atomic Absorption Spectrometry     

Shigeru Terashima 《Geostandards and Geoanalytical Research》1997,21(1):93-96

The molybdenum (Mo) contents of fifty three geochemical reference materials issued by ANRT, GIT-IWG, NIST and GSJ, have been determined by atomic absorption spectrometry, using a graphite furnace atomiser, after extraction of Mo dithiol with isoamyl acetate. Detection limits for this method (0.01 μg g⁻¹) are ten times smaller than for most classical methods. The agreement between the present results and published data is satisfactory.  相似文献   

1994 COMPILATION OF ANALYTICAL DATA FOR MINOR AND TRACE ELEMENTS IN SEVENTEEN GSJ GEOCHEMICAL REFERENCE SAMPLES, "IGNEOUS ROCK SERIES"   总被引：1，自引：3，他引：1  

Noboru IMAI  Shigeru TERASHIMA  Shiro ITOH  Atsushi ANDO 《Geostandards and Geoanalytical Research》1995,19(2):135-213

Analytical data for minor and trace elements published or communicated to us, on seventeen GSJ (Geological Survey of Japan) reference samples, "Igneous rock series" received up to April 1994 are compiled. The data were evaluated statistically in consideration of analytical methods. Based on the selected available data, 1994 recommended and proposed values for 65 minor and trace elements are presented.  相似文献   

TWO NEW GSJ GEOCHEMICAL REFERENCE SAMPLES: SYENITE JSY-1 AND MANGANESE NODULE JMN-1     

Shigeru TERASHIMA  Akira USUI  Noboru IMAI 《Geostandards and Geoanalytical Research》1995,19(2):221-229

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