巻号一覧
43 巻 (2009)
- 6 号 p. 395-
- 5 号 p. 293-
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43 巻, 5 号
選択された号の論文の12件中1～12を表示しています
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YI DUAN, JIANGONG WANG, BAOXIANG WU, CHAOYANG ZHENG, WENXIU YU, GUODON ...2009 年 43 巻 5 号 p. 293-304
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーThe Gasikule oilfield, including a deep layer E31 and a shallow layer N21 pool, is the largest one in the Qaidam Basin and its crude oil output accounts for 80% of total oil output in the basin. In order to understand the genetic mechanism of crude oils from this oilfield, crude oils from both E31 and N21 pools in the Gasikule oilfield were collected and analyzed using gas chromatography and gas chromatography-mass spectrometry. The geochemical characteristics of biomarkers in the crude oils were synthetically studied. The biomarker compositions indicate that the crude oils were derived from strong anoxic and saline-hypersaline lacustrine environment with a dominance of algal organic matter. It was also observed that the ancient salinity of the sedimentary environments of the source rocks for the N21 crude oils was slightly higher than that for the E31 crude oils. The E31 crude oils were derived mostly from bacteria whereas the N21 crude oils originated mostly from plankton. The maturity parameters of biomarkers reflect that the crude oils were low mature. The maturity of the E31 crude oils was slightly higher than that of the N21 crude oils. These results, together with research of crude oil formation, show that the N2 and E31 crude oils were yielded from free biological lipids, extractable organic matters and kerogen in the Tertiary source rocks deposited under an anoxic and saline-hypersaline environment at the stage of low maturity.抄録全体を表示PDF形式でダウンロード (1556K) -
JINYOUNG JUNG, YUWOON JANG, RICHARD ARIMOTO, MITSUO UEMATSU, GANGWOONG ...2009 年 43 巻 5 号 p. 305-314
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーAtmospheric wet and dry deposition samples collected from three sites (Hwasung, Ansan and Daeboo) around Lake Sihwa, South Korea were used to calculate the atmospheric deposition of nitrogen to the lake and to evaluate its effects on primary production. The analytical parameters included pH, conductivity, and cation (Na+, NH4+, K+, Mg2+, Ca2+) and anion (Cl-, NO3-, SO42-) concentrations. The monthly volume-weighted mean pH of the rainwater ranged from 3.9 to 5.1, with a mean of 4.5, thus showing moderate to strong acidification. Factor analysis indicated that the possible sources for the major ions in the precipitation were anthropogenic/crustal, marine and biomass burning products. Wet deposition varied with season; the highest flux of inorganic nitrogen (NO3--N + NH4+-N) occurred in the summer and averaged 160 mg/m2/month. Less nitrogen was delivered by dry deposition which was highest in spring 2004 (March-May, 23 and 50 mg/m2/month for NO3--N and NH4+-N, respectively). The total annual atmospheric deposition of NH4+-N (1100 mg/m2/yr) was about twice that of NO3--N (560 mg/m2/yr). The combined direct deposition to the lake proper was 7.1 × 107 g-N/yr while the estimated annual flux to the entire Lake Sihwa basin was 7.9 × 108 g-N/yr. Of the total atmospheric inorganic N entering Lake Sihwa (2.7 × 108 g-N/yr), 26% was from direct deposition and 74% from indirect deposition. To estimate the potential impact of atmospheric nitrogen on primary production in the lake, chlorophyll-a equivalents were calculated assuming Redfield stoichiometry; this was estimated to be about 8% of the total chlorophyll-a produced in 2004.抄録全体を表示PDF形式でダウンロード (276K) -
HIDEYOSHI YOSHIOKA, SUSUMU SAKATA, BARRY A. CRAGG, R. JOHN PARKES, TET ...2009 年 43 巻 5 号 p. 315-321
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーGas hydrates and associated high methane concentrations are widely distributed along the boundary of the Nankai Trough off Japan. Radiotracer activity measurements were conducted to estimate current methane production rates in sediment cores at two sites in the eastern Nankai Trough off Tokai containing gas hydrates. Low rates of methanogenesis from CO2 reduction and acetate fermentation were detected within the gas hydrate-stability zone and below the Bottom Simulating Reflector (BSR), but not in sediments from shallow depths (<100 mbsf). The detected production rates of methane from acetate were much higher than those from carbon dioxide and hydrogen. Methanol or potentially some other methyl compounds could also be used for microbial methane production. Deep methane production rates from acetate in the gas hydrate-bearing sediments were higher than in pre-accretionary, hydrate-free sediments at sites 1173, 1174 and 1177 of ODP Leg 190 from the floor of the western Nankai Trough off Shikoku Island. As previously suggested this might be due to upward fluid flow stimulating bacterial activities around and below the base of the gas hydrate zone. In contrast, methanogenesis from carbon dioxide and hydrogen was the main pathway for microbial methane production in the hydrate-free sediments at the ODP Nankai Trough sites.抄録全体を表示PDF形式でダウンロード (330K) -
JUN-ICHI MATSUDA, KAZUHIKO MORISHITA, MASAYUKI NARA, SACHIKO AMARI2009 年 43 巻 5 号 p. 323-329
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーWe report Raman spectroscopic results of four density-separated fractions of a floating fraction (material similar to HF-HCl residues enriched in heavy noble gases) of the Allende meteorite. The Raman analyses were performed at two laser powers of 0.5 mW and 2-6 mW with the excitation wavelength of 532 nm. The typical Raman spectra of carbon were observed for all the samples, but these carbonaceous materials were very sensitive to the laser power at the analysis. The Raman parameters except for the intensity ratio of D band and G band are similar in all the fractions at the low laser power, but they changed at the high laser power in a different manner, probably due to the different degree of laser-induced heating. Our findings are that phase Q (the carrier of noble gas of the normal isotopic composition in meteorites) is enriched in the graphitic carbon having larger domain size compared to the major carbon in Allende and that this carbon is most affected by the laser heating.抄録全体を表示PDF形式でダウンロード (442K) -
MIHO ITO, KYOKO YAMAOKA, HARUE MASUDA, HODAKA KAWAHATA, LALLAN P. GUPT ...2009 年 43 巻 5 号 p. 331-341
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーSiliceous ooze was reacted with NaCl solution at temperatures of 100-250°C to evaluate the effect of the mineralogical and chemical properties of host sediments on the thermal stability of amino acids (AAs). Results were compared with those previously reported from calcareous ooze. The siliceous ooze preserved more AAs than did the calcareous ooze, and the solution with the siliceous ooze preserved the AAs for a longer time than did the solution with the calcareous ooze. When siliceous ooze was reacted under hydrothermal conditions, the AAs were released easily and were more stable in alkaline solution than in the NaCl solution. Solubility of silica was greater in alkaline solution than in NaCl solution, and an excess of hydroxyl ion and/or carbonate species in the alkaline solution underwent exchange more frequently with AAs in the siliceous ooze than in the NaCl solution. The thermal stability of neutral AAs was enhanced significantly in alkaline solution at temperatures higher than 200°C. When montmorillonite and saponite were heated in NaCl solution with a known amount of AAs at 250°C, some AA concentrations increased, probably due to negatively charged AAs binding to cations in the clay minerals. The results suggest that the AAs are dissolved into the solution from the sediments primary via ion exchange, and that polymerization of silica that included AAs in its framework stabilized AAs in siliceous ooze.抄録全体を表示PDF形式でダウンロード (382K) -
URSZULA SKRET, MONIKA J. FABIANSKA2009 年 43 巻 5 号 p. 343-369
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーOrganic matter occurring in Lower Palaeozoic rocks of variable lithology was investigated for its origin, depositional environment and thermal maturity. Samples from nine boreholes located in the Polish part of the Peribaltic Syneclise were collected for performing Rock-Eval Analysis, palynological investigation for Thermal Alteration Index (TAI), solvent extraction, preparative layer chromatography (PLC) and gas chromatography-mass spectrometry (GC-MS) of aliphatic and aromatic compound fractions. It was found that kerogen belongs to either type I or commonly, to type II. It derives from variable, planktonic and planktonic-bacterial primary organic matter deposited in dysoxic environments in the eastern part of the Syneclise and in anoxic/suboxic conditions in the western and central parts. Organic matter is in the thermal evolution stage from late diagenesis to advanced metagenesis. Correlation of biomarker parameters, TAI and Rock-Eval results show that the thermal maturity of organic matter falls into three regional groups, increasing from the north-east to the south-west along the crystalline basement of the Eastern European Platform. The organic matter contained in Ordovician and Cambrian sediments of the western part of the Syneclise is overmature, reaching metagenesis. This is most probably related to the activity of the Teisseyre-Tornquist Zone, where the Baltica and Eastern Avalonia paleocontinents collided during the Late Ordovician. It is also reflected in the profiles by elevated values of aromatic hydrocarbon and sulphur compound parameters, which show the highest levels of thermal maturity for organic matter present in the sediments of the Ordovician and Lower Silurian. Local influence of igneous intrusions on organic matter is also visible in changes in thermal maturity values at the direct contact with diabase dykes.抄録全体を表示PDF形式でダウンロード (1390K) -
XUE-MING YANG, DAVID R. LENTZ2009 年 43 巻 5 号 p. 371-377
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーThis study presents a numerical method to estimate the mole fractions of sulfate species in magmatic rocks using sulfur isotopes, which can be illustrated in a δ-δ diagram. The mole sulfate ratio in an igneous rock sample can be calculated from the δ34Srock value of the whole-rock sample and the δ34Ssulfide (or δ34Ssulfate) value of a sulfide and (or) a sulfate mineral (species) in the sample on the basis of S-isotope fractionation and mass balance under the conditions of magmatic equilibrium. This method can be used to test if magmatic equilibrium between sulfate and sulfide species in magmatic rocks is retained, and to predict the δ34S value of one of them at a certain temperature if sulfur isotopic equilibrium is maintained. The initial sulfur isotope composition of the system in question may be estimated based on a set of samples from an igneous suite. Mole sulfate ratio in the magmatic rocks is then used to estimate redox conditions under which they are formed. This practice is important in understanding the genesis of mineral deposits associated with magmatic rocks.抄録全体を表示PDF形式でダウンロード (119K) -
HUI YAN, XINQING LEE, HUI ZHOU, HONGGUANG CHENG, YAN PENG, ZHIHONG ZHO ...2009 年 43 巻 5 号 p. 379-387
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーBivalve shells have been used in a number of paleoclimate and paleoenvironment studies. In order to investigate oxygen and carbon isotope fractionation between bivalve aragonite and host water, a one year monitoring experiment was conducted. Temperature, δ18OWATER and δ13CDIC were measured every week from January 2006 to January 2007. These data were used to calculate expected δ18O and δ13C equilibrium values to compare to measured shell values. At the end of the monitoring experiment, living bivalves (Corbicula fluminea) were collected and sampled for stable isotope analysis (δ18Oar and δ13Car). Comparison of shell δ18O with expected values revealed precipitation of δ18O in equilibrium with the ambient environment from early spring to early fall. Winter values were not recorded due to winter growth cessation. Cooler temperatures seem to cause cessation of growth, suggesting that a threshold temperature may control the onset and cessation of growth. Shell δ13C are more negative than predicted δ13C values, and we observed that all the specimens showed a trend of lower δ13C values with increasing age, this suggests that the incorporation of metabolic carbon is the cause of the negative offset in shell δ13C. The variable offset from equilibrium δ13C values precludes the direct use of Corbicula fluminea shell in the study of the δ13CDIC in ancient bodies of water.抄録全体を表示PDF形式でダウンロード (1223K)
Note
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ASAKO TAKAMASA, SHUN'ICHI NAKAI2009 年 43 巻 5 号 p. 389-394
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーWe examined blanks during powdering processes for thirty-three trace elements using ICP-MS (inductively coupled plasma mass spectrometry). Quartz sand was used as target of powdering with grinding mills of several kinds: an agate hand mill, agate ball mill, Fe hand mill, alumina ceramic hand mill and artificial crystalline quartz hand mill. The results show that the artificial crystalline quartz hand mill is the purest grinder among the analyzed ones. This grinder is suitable for soft rock samples such as limestone. The alumina ceramic hand mill can reduce contamination, except for Cs, W and Pb. The agate hand mill and the agate ball mill introduce contamination whose level is depending on the individual device due to heterogeneity of the natural agate. The Fe hand mill introduces contamination of some siderophile elements such as Mo and W. The results of this study emphasize careful choice of a grinding mill for sample pulverizing.抄録全体を表示PDF形式でダウンロード (209K)
Express Letters
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KUMIKO FUJIMOTO, SHOICHI ITOH, SHINGO EBATA, HISAYOSHI YURIMOTO2009 年 43 巻 5 号 p. e11-e15
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーOxygen isotopic compositions of metal grains in a noble-gas-rich chondrite, NWA 801 CR2, have been determined by secondary ion mass spectrometry. The results show bimodal distribution on Δ17O histogram with peaks of Δ17O = 2.3 and -35.0‰. The 16O-rich peak seems to be due to stellar wind from the protosun. The 16O enrichment is comparable with the most 16O-rich value from chondrite constituents. Difference of oxygen isotopic composition of stellar wind between protosun and the present sun implies how self-pollution by planetary embryos during the planet formation epoch have occurred and whether the present solar photosphere preserves the representative composition of the solar system.抄録全体を表示PDF形式でダウンロード (307K) -
MOTOKO YOSHIZAKI, TAKAZO SHIBUYA, KATSUHIKO SUZUKI, KENJI SHIMIZU, KEN ...2009 年 43 巻 5 号 p. e17-e22
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーHydration of komatiite can be a source of significant amount of hydrogen in the Hadean and early Archean ocean floor. We report the first direct evidence for this process based on the results of our hydrothermal alteration experiments on the synthetic komatiitic glass at 300°C and 500 bars. Komatiitic glass was synthesized by dehydration and remelting of serpentinized Al-depleted komatiite collected from the early Archean Komati Formation, the Barberton Greenstone Belt, South Africa. Though the run is still continuing in our lab, the observed accumulation of hydrogen (2.4 mmol/kg) over 2,600 hours is truly significant and is comparable to those observed by hydration of peridotitic rocks. Our results suggest that hydrothermal alteration of komatiites may have provided the source of H2 in the vicinity of hydrothermal vents that fueled the early evolution of living ecosystems in the Hadean and early Archean.抄録全体を表示PDF形式でダウンロード (185K) -
HIROSHI TANIMOTO, YASUNORI TOHJIMA, HITOSHI MUKAI, HIDEKI NARA, SHIGER ...2009 年 43 巻 5 号 p. e23-e29
発行日: 2009/10/20
公開日: 2011/04/20
ジャーナル フリーAn anomalously low carbon monoxide (CO) episode was observed at Cape Ochi-ishi located in northern Japan in summer 2004. The low CO episode persisted for as long as twelve days from July 27 to August 7, 2004, and the CO levels at Cape Ochi-ishi during this episode were comparable to at Hateruma Island, a southernmost island of Japan. We explored regional distributions of CO and roles of synoptic-scale meteorology in this episode by using a regional chemistry-transport model. The model reproduced the observed levels and day-to-day variations of CO very well, and indicated that the low CO episode widely occurred around Japan. The model simulations revealed the presence of steep gradient in central Hokkaido, explaining the observed differences in CO mixing ratios between Cape Ochi-ishi and Rishiri Island. The eleven-year model results and backward trajectories suggested that the low CO event observed in 2004 was due to rapid transport of pristine air masses from the Pacific Ocean, driven by anomalously stronger easterly flows in the summer of 2004. This mechanism well explained the anomalous patterns observed for methane, carbon dioxide, and molecular hydrogen associated with low CO.抄録全体を表示PDF形式でダウンロード (1468K)
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