巻号一覧
27 巻 (1993)
- 6 号 p. 367-
- 4-5 号 p. 181-
- 3 号 p. 131-
- 2 号 p. 59-
- 1 号 p. 1-
27 巻, 1 号
選択された号の論文の5件中1～5を表示しています
- |<
- <
- 1
- >
- >|
-
Kuninao Tada, Yoshiaki Maita1993 年 27 巻 1 号 p. 1-5
発行日: 1993/02/20
公開日: 2008/04/08
ジャーナル フリーDissolved proteinaceous materials in surface seawater in Funka Bay, Hokkaido, Japan were fractionated according to their molecular weight and analyzed for their amino acid composition by HPLC. Ultrafiltration membranes with different nominal cut-off sizes were used to fractionate the proteinaceous materials into molecular weight classes of approximately 500, 10, 000, and 100, 000 daltons. Amino acid content in the low molecular weight fraction (500 to 10, 000 daltons) accounted for 57 and 80% of the total amino acid contents in proteinaceous materials. The amino acid composition of this fraction was characterized by a relatively high abundance of cystine (10 to 15% of total amino acid content) during a spring bloom of phytoplankton. It was suggested that the high abundance of cystine in the fraction was caused by the spring bloom of diatom.抄録全体を表示PDF形式でダウンロード (1203K) -
Bruno Capaccioni, Marino Martini, Filippo Mangani, Luciano Giannini, G ...1993 年 27 巻 1 号 p. 7-17
発行日: 1993/02/20
公開日: 2008/04/08
ジャーナル フリーGeochemical investigation of gas emissions at low temperatures in areas of Quaternary volcanism shows a systematic enrichment of aromatic hydrocarbons and alkenes in fumaroles from active volcanic areas (Vulcano and Phlegrean Fields, Italy; S. Miguel, Terceira and Graciosa, Azores; Chichòn, Mexico; Uzon and Geyser Valley, Kamchatka) and geothermal systems (Larderello area, Italy) with respect to those pertaining to areas of recent but exhausted volcanism (Vulsini and Sabatini volcanic districts, Torre Alfina volcano, Italy). The general behaviour of hydrocarbons in the investigated gas-emissions, together with thermodynamic and experimental data (taken from the industrial treatment of petroleum) suggest possible abiogenic processes acting on degradation of alkane hydrocarbons when source temperatures exceed 150° and acid species together with high active-surface area clay minerals are available. Benzene shows very similar enrichments in emissions from Vulcano beach and Phlegrean Fields, Kamchatka and Azores, pointing out the possible occurrence of catalytic reactions at the source. Alkenes display significant relative increases in crater fumaroles from Chichòn volcano. Moreover, lower carbon-number alkenes (propene and ethene) progressively appear with increasing alkenes/alkanes ratio, suggesting an increasing importance of thermal-cracking reactions. The general similarities in distribution patterns from different active volcanic environments allow us to reappraise the influence of the nature of sources and to emphasize the effects of abiogenic reactions. With reference to areas of active volcanism, the distribution of hydrocarbons can represent a useful parameter to evaluate the prevailing physico-chemical conditions and their time-space variabilities. Accordingly they can give a significant contribution to the geochemical monitoring of active volcanic areas.抄録全体を表示PDF形式でダウンロード (2955K) -
Yoshikazu Kikawada, Takao Oi, Teruyuki Honda, Tomoko Ossaka, Hidetake ...1993 年 27 巻 1 号 p. 19-33
発行日: 1993/02/20
公開日: 2008/04/08
ジャーナル フリーThe lanthanoid (Ln) contents of nine hot spring and one crater lake waters in the Kusatsu-shirane volcano region, Japan were measured by neutron activation analysis. The waters examined were all acidic with pH ranging from 1.21 to 4.21. All fourteen naturally occurring Ln's were determined for six waters and at least seven Ln's were determined for the other waters. The Ln contents were as a whole at the ppb levels. The Ln patterns obtained by normalization with the Ln contents in Leedey chondrites differed from water to water but were classifiable into two groups; one with a relative enrichment of the light Ln's and thus showing negative slopes and the other having no or little slope (horizontal patterns). The horizontal patterns were found for the Kusatsu-yubatake and Bandaiko hot spring waters and the Yugama water. The Ln patterns of the waters in the Kusatsu area are explained by considering that the light Ln's are leached from rock by flowing acidic waters faster than the heavy Ln's, that in the Ln distribution between acidic water with high Ln contents and rock the heavy Ln's are relatively more preferentially distributed into the solution phase than the light Ln's are, and in addition that andesitic rocks in the Kusatsu area altered by flowing acidic waters have flatter Ln patterns than those of unaltered ones. It was also found that the fluctuation of the Ln pattern from the expected smooth line was in general larger for the heavy Ln's than for the light Ln's, which could be a manifestation of the tetrad effect.抄録全体を表示PDF形式でダウンロード (4466K) -
Lin-Gun Liu1993 年 27 巻 1 号 p. 35-47
発行日: 1993/02/20
公開日: 2008/04/08
ジャーナル フリーIn comparison to the MgO–SiO2–H2O (MSH) system, the addition of Al2O3 (as required in the pyrope composition) makes the effects of H2O on the high-pressure phase behavior of pyrope extremely complicated. This is because the MgO–Al2O3–SiO2–H2O (MASH) system involves more than twice as many crystalline hydrous phases as the MSH system. Experimental investigations of the effect of H2O on the phase behavior of pyrope have so far revealed only three phase assemblages plus various unidentified assemblages in the pressure range 1.5–3.5 GPa and in the presence of excess H2O. Thus, a theoretical study based on the ambient densities of various phase assemblages which are relevant to the pyrope-H2O composition at various H2O content and at high pressures and temperatures is undertaken in the present work. The results of the present study not only shed light on the unidentified phase assemblages revealed in the experimental studies involving excess H2O, but also predict many possible phase assemblages at any given amounts of H2O up to pressures of a few tens of GPa. The high-pressure ilmenite form of pyrope is predicted not to exist when more than 1.1 wt% H2O is present. For a model mantle which is rich in pyrope and contains less than 1 wt% H2O, the three polymorphs of Mg3Al2Si3 O12 (pyrope, ilmenite and perovskite) would diversify into more than ten phase assemblages which contain various hydrous phases at various pressure and temperature conditions. The effect of H2O on the phase behavior of an aluminous enstatite, which is a more likely candidate than both enstatite and pyrope in the Earth's mantle, is closer to pyrope than to enstatite at high pressures and temperatures.抄録全体を表示PDF形式でダウンロード (3604K) -
Yasuhiro Kiyosu, H. Roy Krouse1993 年 27 巻 1 号 p. 49-57
発行日: 1993/02/20
公開日: 2008/04/08
ジャーナル フリーReaction between sodium sulfate and acetic acid under hydrothermal conditions has been investigated in order to demonstrate the thermochemical reduction of seawater sulfate by organic matter at moderate temperatures during diagenesis. Although no reduction of sodium sulfate occurred directly, the sulfate was reduced by acetic acid to hydrogen sulfide in the presence of native sulfur over the temperature range of 200–270°C. The sulfur isotopic behavior of sulfur compounds suggests that the isotope fractionations are not controlled by kinetic isotope effects but rather by the isotope exchange reaction between the sulfate and sulfide.抄録全体を表示PDF形式でダウンロード (2204K)
- |<
- <
- 1
- >
- >|