巻号一覧
35 巻 (2001)
- 6 号 p. 385-
- 5 号 p. 277-
- 4 号 p. 215-
- 3 号 p. 145-
- 2 号 p. 77-
- 1 号 p. 1-
35 巻, 3 号
選択された号の論文の14件中1～14を表示しています
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Yishan Zeng, Yongfeng Zhu, Jiaqi Liu2001 年 35 巻 3 号 p. 145-153
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーIn order to verify the presence of residual organic matter in some S-type granites, a method used conventionally in petroleum geochemistry for isolation of kerogen was employed to separate carbonaceous material (CM) from the Xihuashan granite, Jiangxi Prov., China. Optical, XRD and SEM/EDAX analyses identified the acid-insoluble residue as mainly composed of various mineral debris, with a minor carbonaceous fraction found in the residue. LMR and micro-FTIR studies showed that the residue contained a small amount of CM, which is heterogeneous in composition and structural state. The occurrence of CM in the granite implies that this granitic magma originated from sediments and crystallized at relatively lower temperatures and high pressures. This deduction is consistent with geological and geochemical studies of the Xihuashan granite. A tentative model was suggested which connects CM in S-type granite with organic matter in sedimentary rocks. The conditions under which CM can be preserved in S-type granite are discussed. The occurrence of some heavy hydrocarbons is expected in the Xihuashan granite.抄録全体を表示PDF形式でダウンロード (1378K) -
Zhi-nong Gao, Yuan-yin Chen, Fei Niu2001 年 35 巻 3 号 p. 155-168
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーSolid bitumens found in carbonate rocks of the Shiwan Dashan basin, south China, are suggested to have been matured under high pressure and moderate temperature conditions. These bitumens have different geochemical characteristics from thermally matured bitumen: very high bitumen reflectance (ROB) values and compact molecular structures (bigger size of crystal nucleus, more layer number of aromatic cycle, lower lamellar distance and so on) in spite of the chemical components reflecting lower thermal maturity. Therefore these are named as compressively matured bitumen. The geochemical characteristics of the compressively matured bitumens result from increase in its crystalline degree (grain size) under high pressures, not at high temperatures. The compressively matured bitumens retain chemical composition, molecular evolution parameters (associated with their chemical components) and hydrocarbon-producing potential similar to those of thermally less mature bitumens. High temperature and high pressure experiments proved that pressure and temperature have similar effect on the maturation indices, such as ROB values and molecular structures. The above contrasting geochemical characteristics can be used to distinguish the compressively matured bitumens from thermally matured bitumens.抄録全体を表示PDF形式でダウンロード (896K) -
Yasutaka Terakado2001 年 35 巻 3 号 p. 169-174
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーRe-Os dating method was applied to the Kuroko ores from of the Wanibuchi Mine, southwestern Japan. Two whole-rock Kuroko ores and two yellow color fragments separated from one Kuroko ore sample were analyzed. Their Re and Os concentrations range from 3.52 to 50.6 ppb and from 20.1 to 92.9 ppt, respectively, and their 187OS/188Os ratios vary from 0.911 to 1.609. These data yield an isochron age of 18.44 ± 0.60 Ma with initial 187Os/188Os of 0.621 ± 0.013. The age is older than the inferred Kuroko formation age of northeastern Kuroko deposits, and also about three Ma older than the time of the clockwise rotation of southwestern Japan (ca. 15 Ma). The Wanibuchi Kuroko deposits are considered to have formed at the waning stage of the first phase (28–18 Ma) of the rifting and seafloor spreading in the Japan Sea area. The initial 187Os/188Os ratio might reflect the contemporaneous local seawater ratio that was more affected by mantle-derived Os resulted from the volcanic activities of Japan Sea formation than the typical oceanic Os ratio.抄録全体を表示PDF形式でダウンロード (469K) -
Seung-Gu Lee, Akimasa Masuda, Hiroshi Shimizu, Yong-Sun Song2001 年 35 巻 3 号 p. 175-187
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーThe Precambrian basement of the Korean Peninsula, located at the east margin of Asian continent, consists of the Nangrim Massif, the Gyeonggi Massif and the Sobaegsan (Yeongnam) Massif. Two kinds of orthogneisses (biotite gneiss and granitic gneiss) from the central part of the Sobaegsan Massif show the particular difference in geochemical features suggesting the discrimination in formation history. The biotite gneisses give an Sm-Nd whole rock isochron age of 819 ± 114 Ma (2σ) with εNd (0.82 Ga) = −15, and the granitic gneisses give an age of 1484 ± 810 Ma (2σ) with εNd (1.48 Ga) = +7. The εNd and εCe, values for the granitic gneisses show characteristics of highly depleted mantle material and those of the biotite gneisses show their sources having light-REE enriched continental-like feature. Chondrite-normalized REE patterns are also different. Biotite gneisses have less fractionated patterns with (La/Yb)N ratio of 10∼16 and negative Eu anomalies, while granitic gneisses have fractionated patterns with (La/Yb)N ratio of 30∼180 with no/or positive Eu anomalies. The Ce-Nd isotopic results obtained here indicate that the Sobaegsan biotite gneisses were derived from continental-like sources having light-REE enriched feature, while the Sobaegsan granitic gneisses were derived from MORB-like sources having light-REE-depleted feature. These isotopic and REE data are interpreted as recording LREE fractionation events associated with major episodes of crust formation in East Asia. And the comparison of the initial εNd value of the Sobaegsan biotite gneiss at 0.82 Ga with those of the Chinese and Japanese Precambrian rocks implies that the sources for the Sobaegsan biotite gneisses and these Chinese and Japanese rocks had common light-REE enriched pattern, e.g., 147Sm/144Nd ratio ranging from 0.09–0.13. Furthermore, it suggests that these sources having light-REE enriched patterns were derived from depleted mantle at the late Archean.抄録全体を表示PDF形式でダウンロード (1889K) -
Yoshikazu Sampei, Eiji Matsumoto2001 年 35 巻 3 号 p. 189-205
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーThe weight ratio of total organic carbon to total nitrogen (C/N ratio) in 20 meters of sediment core from Nakaumi Lagoon (coastal brackish lake), Japan is examined for its suitability as an organic source indicator. The C/N ratio depth profile is compared to the depth profiles of other proxies, i.e., weight ratio of total organic carbon to total organic nitrogen (C/Norg. ratio), stanol compositions, n-alkane compositions and the hydrogen-index by Rock-Eval pyrolysis. The C/N ratios of the lagoonal sediments, which have been deposited over the last ca. 8, 000 years, have a different profile from that of the C/Norg. ratio and other proxies due to the effects of a constant level of inorganic nitrogen (Ninorg.: ca. 0.04%) in the sediments. When Corg. content is less than 1 wt%, the presence of Ninorg. lowers the C/N ratio considerably, giving an inaccurate indication of organic source. C-N and C/N ratio–Corg. plots are useful for evaluating the effect of Ninorg.; if the depth profiles of the C/N ratio and Corg. content exhibit similar trends, this is taken as a warning that the apparent variation in the C/N ratio should be carefully examined in conjunction with the other plots and proxies. It is also found that the C/Norg. ratio itself also tends to increase due to the preferential decomposition of nitrogen compounds, and that in sediments containing high proportions of planktonic organic matter (OM), the sensitivity of the C/N ratio to changes in the proportions of planktonic-terrestrial OM is relatively low.抄録全体を表示PDF形式でダウンロード (1053K) -
Katsuhiko Suzuki, Yoshiyuki Tatsumi2001 年 35 巻 3 号 p. 207-210
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーOsmium and Reabundance and 187Os/188Os ratios of reference rocks, JB-1a, JA-2 and JP-1, were determined through isotope dilution—negative thermal ionization mass spectrometry (ID-NTI-MS). Duplicate analyses of each sample show heterogeneous distribution of Re and Os in the reference rocks. The ranges of Re and Os concentrations are 150–200 and 9–12 ppt for JB-1a, 59–67 and 10–12 ppt for JA-2 and 28–32 and 2400–2700 ppt for JP-1, respectively. Extremely high 187Os/188Os ratios of 0.20–0.28, much higher than that of the chondritic mantle (0.12–0.13), of JB-1a and JA-2 indicates involvement of components with highly radiogenic 187Os/188Os ratios such as the subducting slab-derived materials. The reference rocks JP-1, Horoman peridotite, yields sub-chondritic Os isotopic composition of 0.12.抄録全体を表示PDF形式でダウンロード (23K) -
Oliver K. Manuel2001 年 35 巻 3 号 p. 211-212
発行日: 2001/06/20
公開日: 2008/04/08
ジャーナル フリーPDF形式でダウンロード (391K) -
2001 年 35 巻 3 号 p. e1a
発行日: 2001年
公開日: 2009/02/06
ジャーナル フリーPDF形式でダウンロード (9K) -
2001 年 35 巻 3 号 p. e1b
発行日: 2001年
公開日: 2009/02/06
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2001 年 35 巻 3 号 p. e1c
発行日: 2001年
公開日: 2009/02/06
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2001 年 35 巻 3 号 p. e1d
発行日: 2001年
公開日: 2009/02/06
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2001 年 35 巻 3 号 p. e1e
発行日: 2001年
公開日: 2009/02/06
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2001 年 35 巻 3 号 p. e1f
発行日: 2001年
公開日: 2009/02/06
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2001 年 35 巻 3 号 p. e1g
発行日: 2001年
公開日: 2009/02/06
ジャーナル フリーPDF形式でダウンロード (9K)
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