Diagenetic behavior of manganese in Tokyo Bay sediment     

Masahiro Sakata  Yasushi Kitano  Eiji Matsumoto 《Journal of Oceanography》1981,37(4):212-217

To understand the behavior of manganese in diagenetic processes in sediments of an enclosed bay which is similar to those of an estuary, chemical analyses have been carried out on both sediment and interstitial water of a core sample collected from Tokyo Bay. The results suggest that redistribution of manganese takes place within the sediment as a result of the dissolution of buried manganese oxides and hydroxides under reducing condition, the downward diffusion of Mn²⁺ through the interstitial water toward lower layers and then the precipitation of carbonate. The carbonate formed in the sediment contains managanese carbonate probably as a solid solution between calcitic calcium carbonate and manganese carbonate.  相似文献   

The distribution of suspended particles in the Southern Beaufort Sea     

Eiji Matsumoto  C. S. Wong 《Journal of Oceanography》1977,33(4):227-233

The Mackenzie River estuary serves as an avenue for suspended particles to pass seaward. The horizontal distribution of surface suspended particles is compartible with the distribution of low-salinity surface waters. The water structure in the shelf area is highly stratified in summer due to a thin upper layer of low-salinity which has a high concentration of suspended particles. The concentration of suspended particles decreases with depth, but near the bottom a turbid layer had often been observed. It is likely that bottom current energy high enough to erode and maintain in suspension the bottom sediments below 15m in diameter does occur over this shelf area.  相似文献   

Distribution of oxygen-containing functional groups and elements in humic acids from marine sediments     

Yoshiji Saito  Shigeo Hayano 《Journal of Oceanography》1980,36(1):59-67

The elemental composition and oxygen-containing functional groups contents in the marine humic acids from the five sediment samples from Sagami Bay and Suruga Bay were determined. Kumada's method of classification of soil humic acids was applied to the marine humic acids. The carbon, nitrogen, hydrogen, oxygen and sulfur contents of the marine humic acids were, on average, 52.96, 5.12, 5.79, 34.99 and 1.13%, respectively, without wide variation. In comparison with terrestrial humic acids, the marine ones had relatively lower carbon content and higher hydrogen and nitrogen contents. It is suggested that the marine humic acids have more aliphatic and less aromatic character, as expected from their possible origins, e.g., phytoplankton. The total acidity, carboxyl, phenolic and alcoholic hydroxyl, carbonyl and methoxyl group contents in the marine humic acids were, on average, 5.80, 3.27, 2.53, 2.53, 3.09 and 0.41 milliequivalents per gram of dry ash-free humic acid (me g^–1), respectively. From quantitative data on the elemental composition and functional groups of the average marine humic acid, its empirical formula was calculated to be C₁₀₇H₁₃₈O₂₀(COOH)₉(OH)₇ ^phenolic (OH)₇ ^alcoholic (CO)₉(OCH)₃N₁₀S. The marine humic acids were similar to the so-called B type of soil humic acids with regard to the distribution of functional groups and spectroscopic properties.  相似文献   

A simplified analysis method for piled raft foundations subjected to ground movements induced by tunnelling     

Pastsakorn Kitiyodom  Tatsunori Matsumoto  Kanji Kawaguchi 《国际地质力学数值与分析法杂志》2005,29(15):1485-1507

A simplified method of numerical analysis has been developed to estimate the deformation and load distribution of piled raft foundations subjected to ground movements induced by tunnelling and incorporated into a computer program ‘PRAB’. In this method, a hybrid model is employed in which the flexible raft is modelled as thin plates, the piles as elastic beams, and the soil is treated as interactive springs. The interactions between structural members, pile–soil–pile, pile–soil–raft and raft–soil–raft interactions, are modelled based on Mindlin's solutions for both vertical and lateral forces. The validity of the proposed method is verified through comparisons with some published solutions for single piles and pile groups subjected to ground movements induced by tunnelling. Thereafter, the solutions from this approach for the analysis of a pile group and a piled raft subjected to ground movements induced by tunnelling are compared with those from three‐dimensional finite difference program. Good agreements between these solutions are demonstrated. The method is then used for a parametric study of single piles, pile groups and piled rafts subjected to ground movements induced by tunnelling. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Chemical and mineralogical compositions of two grains recovered from asteroid Itokawa          下载免费PDF全文

M. Ebihara  N. Shirai  S. Sekimoto  T. Nakamura  A. Tsuchiyama  J. Matsuno  T. Matsumoto  M. Tanaka  M. Abe  A. Fujimura  Y. Ishibashi  Y. Karouji  T. Mukai  T. Okada  M. Uesugi  T. Yada 《Meteoritics & planetary science》2015,50(2):243-254

Two silicate grains (RB‐QD04‐0049 and RA‐QD02‐0064, whose estimated masses are 0.050 μg and 0.048 μg, respectively) recovered from the asteroid Itokawa by the Hayabusa spacecraft were studied for their mineralogical characteristics by synchrotron X‐ray diffraction and synchrotron X‐ray microtomography and further analyzed for their bulk chemical compositions by instrumental neutron activation analysis (INAA). According to X‐ray tomography, RB‐QD004‐0049 is composed of olivine, high‐Ca pyroxene, plagioclase, Ca‐phosphate, and troilite, whereas RA‐QD002‐0064 entirely consists of olivine. INAA data are consistent with these mineral compositions except for rare earth elements (REEs). Although the grain RB‐QD004‐0049 contains measurable REEs, which seems to be consistent with the presence of Ca‐phosphate, their abundances are anomalously high. Very low abundance of Co implies less than 0.1 mass% of metals in these two grains by calculation, which is in contrast to the result for the previously analyzed grain RA‐QD02‐0049 (Ebihara et al., 2011). FeO/Sc ratios of the grains fall within the range of those for ordinary chondrite olivines, implying that these grains are extraterrestrial in origin. FeO/MnO ratios also confirm this conclusion and further suggest that the Hayabusa grains analyzed in this study are similar to material found in LL chondrites rather than CK chondrites although olivines from LL and CK chondrites have similar Fa# (molar% of Fe relative to [Fe+Mg] in olivine) (~30) to those of the Hayabusa grains including the two grains analyzed in this study.  相似文献   

Influence of weather conditions and spatial variability on glacier surface melt in Chilean Patagonia     

Keiko Konya  Takane Matsumoto 《Theoretical and Applied Climatology》2010,102(1-2):139-149

In order to clarify how differences in weather conditions affect the surface heat balance of a large maritime glacier, meteorological observations were carried out in the ablation area of Glaciar Exploradores in the Chilean Patagonia during the austral summer of 2006/2007. Under cloudy/rainy weather, when the air temperature and wind speed were high due to advection, the average melting heat was 18.8 MJ m^?2 day^?1 and the turbulent heat fluxes contributed 35% of the total melt. During clear weather, the average melting heat was 16.9 MJ m^?2 day^?1 and 13% of the total was the turbulent heat fluxes. A decrease in air temperature due to the development of the glacier boundary layer on clear days will lead to an overestimation of the melt using the air temperature at a weather station outside of the glacier.  相似文献   

Inter-regional correlation of transgressions and regressions in the Cretaceous period   总被引：1，自引：0，他引：1  

T. Matsumoto 《Cretaceous Research》1980,1(4):359-373

Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous.  相似文献   

Earthquake-induced rapid long-traveling flow phenomenon: May 2003 Tsukidate landslide in Japan   总被引：3，自引：2，他引：1  

Hiroshi?Fukuoka  Gonghui?WangEmail author  Kyoji?Sassa  Fawu?Wang  Tatsunori?Matsumoto 《Landslides》2004,1(2):151-155

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Overview of the MITI Nankai Trough Wells: A Milestone in the Evaluation of Methane Hydrate Resources   总被引：4，自引：0，他引：4  

Yoshihiro Tsuji    Hisashi Ishida    Masaru Nakamizu    Ryo Matsumoto  Satoshi Shimizu 《Resource Geology》2004,54(1):3-10

Abstract. Bottom-simulating reflectors suggestive of the presence of methane hydrates are widely distributed below the ocean floor around Japan. In late 1999, drilling of the MITI Nankai Trough wells was conducted to explore this potential methane hydrate resource and a Tertiary conventional structure. The wells are located in the Northwest Pacific Ocean off Central Japan at a water depth of 945 m. A total of six wells were drilled, including the main well, two pilot wells, and three post survey wells at intervals of 10–100 m. All wells except the first confirmed the occurrence of hydrates based on logging-while-drilling, wire-line logging and/or coring using a pressure and temperature coring system in addition to conventional methods. Based on the various well profiles, four methane hydrate-bearing sand-rich intervals in turbidite fan deposits were recognized. Methane hydrates fill the pore spaces in these deposits, reaching saturation of up to 80 % in some layers. The methane hydrate-bearing turbiditic sand layers are less than 1 m thick, with a total thickness of 12–14 m. The bottom depth of high hydrate concentration correlates well with the depth of the bottom-simulating reflector. Based on these exploration results, the Japanese government inaugurated a 16-year methane hydrate exploitation program in 2001.  相似文献   

Surface Heat Balance and Spatially Distributed Ablation Modelling at Koryto Glacier, Kamchatka Peninsula, Russia   总被引：1，自引：0，他引：1  

Keiko Konya  Takane Matsumoto  Renji Naruse 《Geografiska Annaler: Series A, Physical Geography》2004,86(4):337-348

To investigate the characteristics of ablation at Koryto Glacier, a mountain glacier under maritime climate in Kamchatka Peninsula, Russia, we made field observations from August to early September 2000. At a site near the equilibrium line, the 31‐day average net radiation, sensible heat flux, and latent heat flux were 43, 59 and 31 W^?2, respectively. We developed a new distributed ablation model, which only needs measurements of air temperature and global radiation at one site. Hourly ablation rates at this site obtained by the energy balance method are related to measured air temperature and global radiation by linear multiple regression. A different set of multiple regression coefficients is fitted for snow and ice surfaces. Better estimates of ablation rate can be obtained by this approach than by other temperature index models. These equations are then applied to each grid cell of a digital elevation model to estimate spatially distributed hourly melt. Air temperature is extrapolated using a constant temperature lapse rate and global radiation is distributed considering topographic effects. The model enables us to calculate the hourly spatial distribution of ablation rates within the glacier area and could well provide a realistic simulation of ablation over the whole glacier.  相似文献