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Volume 40 (2006)
- Issue 6 Pages 543-
- Issue 5 Pages 425-
- Issue 4 Pages 309-
- Issue 3 Pages 219-
- Issue 2 Pages 121-
- Issue 1 Pages 1-
Volume 40, Issue 3
Displaying 1-8 of 8 articles from this issue
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LIN PENG, YAN YOU, ZHIPENG BAI, TAN ZHU, KECHANG XIE, YIN-CHANG FENG, ...2006 Volume 40 Issue 3 Pages 219-226
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSOrigins of atmospheric polycyclic aromatic hydrocarbons (PAHs) in total suspended particulate (TSP) and particulate matter below 10 micrometers in diameter (PM10) collected in the urban areas of Urumchi and Zhengzhou, China, are discussed on the basis of carbon isotopic compositions of individual compounds. Carbon isotope ratios were measured with the system of GC-C-IRMS with an error (1σ) of less than 0.6‰. δ13C values of atmospheric PAHs in Urumchi range from -23.6‰ to -32.1‰ and from -22.5‰ to -31.0‰ in Zhengzhou. δ13C values of low-weight molecules (pyrene, fluoranthene, benzo[e]pyrene etc.) in PAHs from the two cities are concordant, and range from -23.0‰∼-25.8‰. However, the high-weight individual compounds of atmospheric PAHs in Urumchi are more depleted in 13C with increasing molecular weight of PAHs than those in Zhengzhou. δ13C mean values of benzo[a]pyrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene in Urumchi are -28.3‰, -31.5‰ and -29.7‰, respectively. The values of those three compounds in Zhengzhou, however, are -24.5‰, -29.4‰ and -26.3‰, respectively. Our data, incorporated with the analysis of the consumption of coal and amount of motor vehicles, indicate that PAHs are mainly contributed by coal combustion in the two cities, and the contribution of automobile exhaust to PAHs in Zhengzhou is larger than that in Urumchi during the sampling period.View full abstractDownload PDF (198K) -
N. G. OBAJE, D. O. ATTAH, S. A. OPELOYE, A. MOUMOUNI2006 Volume 40 Issue 3 Pages 227-243
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSSedimentary basins of Northern Nigeria comprise the Middle and Upper Benue Trough, the southeastern sector of the Chad Basin, the Mid-Niger (Bida) Basin, and the Sokoto Basin. Organic geochemical and organic petrologic studies indicate the existence of potential source rocks in the Benue Trough and the Chad Basin, with coal beds constituting major potential source rocks in the whole of the Benue Trough. The generation and production of liquid and gaseous hydrocarbons from coal beds presently is world-wide indisputable.
Although TOC values and liptinite contents are relatively high in the Mid-Niger (Bida) Basin, Tmax values and biomarker data show that hydrocarbons are probably just being generated in the basin and may not yet have been expelled nor migrated in large quantities.View full abstractDownload PDF (1146K) -
E. FOURRE, P. JEAN-BAPTISTE, J.-L. CHARLOU, J. P. DONVAL, J. I. ISHIBA ...2006 Volume 40 Issue 3 Pages 245-252
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSWe present isotopic analysis of helium in hydrothermal fluids from the Manus back-arc basin, collected during the French-Japanese Manusflux and Manaute cruises in 1995 and 2000, respectively. The helium isotope composition of the fluids is comparable to that measured elsewhere in similar subduction environments, with 3He/4He values (7.4 to 7.9 Ra) slightly lower than typical MORB values, except on the Manus Spreading Center (MSC) where higher values (12 ± 0.1 Ra) are observed. The causal link between the narrow spatial extent of the 3He/4He anomaly at the MSC and a 3He-rich deep mantle component remains elusive, based on available geophysical data. Thus, the Manus Spreading Center results may be an interesting example of small scale upper-mantle heterogeneity.View full abstractDownload PDF (333K) -
TAKASHI TOMIYASU, MASAYUKI EGUCHI, HAYAO SAKAMOTO, KATSURO ANAZAWA, RY ...2006 Volume 40 Issue 3 Pages 253-263
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSThe atmospheric concentration of mercury was determined daily for 3 years (July 1999-March 2002) in Kagoshima City to clarify the seasonal variation of mercury levels and the influence of mercury emitted from Sakurajima. The atmospheric mercury was collected on a porous gold collector at Kagoshima University approximately 11 km west of Sakurajima and the amount of mercury was determined by cold vapor atomic absorption spectrometry (CVAAS). A loss of temperature dependency was found for the east wind in 1999. However, in 2001, high temperature dependency was observed for all wind directions with the easing of volcanic activity. Short-term movement in the atmospheric concentration of mercury was also investigated by making measurements every two hours over a three-day period at heights of 3 and 12 m. This operation was carried out about every two months in the year 2001 at Kagoshima University. The atmospheric mercury concentration was higher in the daytime than nighttime showing temperature dependency: the concentration at 3 m (Hg(3m)) ranged from 1.65 to 17.9 ng m-3 (5.96 ± 3.47 ng m-3) in the daytime and 1.50 to 12.8 ng m-3 (4.20 ± 2.33 ng m-3) overnight, while that at 12 m (Hg(12m)) ranged from 1.24 to 29.4 ng m-3 (4.74 ± 3.61 ng m-3) and 1.38 to 14.8 ng m-3 (4.50 ± 2.85 ng m-3), respectively. The variation in Hg(3m) from day to night was considerably larger than that in Hg(12m). As a result, Hg(3m) was higher than Hg(12m) in the daytime and lower in the nighttime. On the other hand, the concentration gradient showed a high degree of dependency on solar radiation. These observations suggested that mercury is emitted from the ground with an increase in solar radiation and rise of the temperature in the daytime and deposits with the fall of temperature at nighttime. The influence of rain and volcanic activity on the periodic variation of mercury is also discussed in detail.View full abstractDownload PDF (357K) -
XIAOQING ZHU, QIAN ZHANG, YULIANG HE, CHAOHUI ZHU, YAN HUANG2006 Volume 40 Issue 3 Pages 265-275
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSThe Meng'entaolegai Ag-Pb-Zn-In polymetallic deposit is located in the eastern part of Inner Mongolia. It consists of a hydrothermal quartz-sulfide vein deposit hosted within a Hercynian granite massif which is about 400 km2 in size. More than 40 orebodies are found in the orefield which is 6 km in length from east to west and 200 to 1,000 m in width from south to north. All orebodies are controlled by E-W trending faults. Economic resources are dominated by Pb and Zn (reserves of Pb and Zn are 0.17 Mt and 0.37 Mt, and their grades are 1% and 2.3%, respectively), with Ag, Sn, In and Cd (1,800 t Ag, >2,000 t Sn, >500 t In and 1800 t Cd) as by-products. The δ34SCDT values of sulfides range from -1.7‰ to +4.6‰, averaging 1.4‰, indicating that sulfur is magmatic in origin. The H-O isotopic compositions (δD values from -52.8‰ to -66.9‰ and δ18OH2O values from 4.8‰ to 7.9‰) of the fluid inclusion water in quartz show that the ore-forming fluid has a mainly magmatic source. The lead isotopic compositions of ore are relatively homogeneous and are significantly lower than those of feldspars and whole rock of the Hercynian Meng'entaolegai granite and the Yanshanian Duerji granite. Neither these granites nor the regional basement Precambrian metamorphic rocks provided ore with lead. By comparison, ore lead isotopic composition is the same as that of E-W trend diorite dykes which intruded the granites and this indicates that the ore lead is probably derived from magamatism which is related to these dykes. We considered therefore that although orebodies occurred within the Hercynian Meng'entaolegai granite, the deposit origin is not related to this stage of magmatism.View full abstractDownload PDF (385K) -
MARCO MAGNANI, TOSHITSUGU FUJII, YUJI ORIHASHI, ATSUSHI YASUDA, TAKAFU ...2006 Volume 40 Issue 3 Pages 277-290
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSMelt inclusions contained in plagioclase and olivine phenocrysts have been studied in tholeiitic basalts from the Shona ridge-centered hot spot region, South Atlantic Ocean. Two types of primitive melt inclusions exist within a hand sample, Normal-Mid Ocean Ridge Basalt (N-MORB) and Enriched-Mid Ocean Ridge Basalt (E-MORB) as defined by trace elements. The N-MORB melt inclusions have low (La/Sm)n (0.54-0.72), high Zr/Nb (22-44) and depleted Light Rare Earth Element (LREE) patterns, whereas the E-MORB melt inclusions have high (La/Sm)n (0.79-1.09), low Zr/Nb (12-21) and flat LREE. The composition of melt inclusions has been modified by post-entrapment crystallization of the host phase, but this effect is considered relatively small and does not affect the incompatible trace element ratios. The matrix glasses have mildly E-MORB compositions that lie between the two different types of melt inclusions, suggesting that they are produced by mixing of primary magmas of E-MORB and N-MORB type.
The N-MORB primitive melt inclusions are geochemically similar to Indian and other South Atlantic N-MORB in having high Ba/Nb ratios (4-10), but for the first time much more extreme values are found (8-18). The reason for this anomalous enrichment can be related to the presence of old pelagic sediments in a regionally depleted asthenosphere.
The melt inclusions of this study display positive anomalies of Sr and Eu, the first time that have been recorded in the South Atlantic. Their characteristics could be explained by partial melting of mantle containing recycled oceanic crust.View full abstractDownload PDF (416K) -
SIMON R. POULSON, HIROSHI NARAOKA2006 Volume 40 Issue 3 Pages 291-296
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSStable carbon isotope fractionation factors associated with the degradation of benzene, trichloroethene (TCE), and tetrachloroethene (PCE) under ultraviolet light (254 nm) have been measured experimentally using simple and inexpensive quartz reaction vessels equipped with a syringe valve and septum. Carbon isotope enrichment factors of εbenzene = -6.2 ± 0.3‰, εTCE = -6.8 ± 0.2‰, and εPCE = -4.1 ± 0.2‰ were obtained. The results demonstrate that the simple and inexpensive experimental design used in this study has potential application to determine isotope enrichment factors associated with degradation under conditions more representative of important atmospheric processes, and hence has future application to the study of the behavior of important trace gases such as non-methane hydrocarbons and other volatile organic compounds in the atmosphere.View full abstractDownload PDF (125K) -
KATSUHIKO SUZUKI, YOSHIYUKI TATSUMI2006 Volume 40 Issue 3 Pages 297-307
Published: 2006
Released on J-STAGE: June 22, 2007
JOURNAL FREE ACCESSHigh-Mg andesites (HMAs) and basalts in the Setouchi volcanic belt exhibit large variations in both Os abundance and Os isotopic composition. For HMAs, 187Os/188Os ratios and Os concentrations range from 0.1718 to 0.2041 and from 8.1 to 11.5 ppt, respectively. For basalts, 187Os/188Os ratios and Os concentration range from 0.1556 to 0.1769 and from 31.0 to 53.7 ppt, respectively. The measured 187Os/188Os ratios are higher than that of the primitive upper mantle estimate. The petrological and geochemical characteristics of HMAs do not support a scenario whereby HMA magmas are derived from basalt magmas via assimilation-fractional crystallization processes within the crust. Instead, the observed elevated Os isotopic compositions may be explained by mixing between the wedge mantle and partial melts from subducted sediments, rather than slab-derived fluids.View full abstractDownload PDF (137K)
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