巻号一覧
21 巻 (1987)
- 6 号 p. 253-
- 5 号 p. 197-
- 4 号 p. 139-
- 3 号 p. 85-
- 2 号 p. 43-
- 1 号 p. 1-
21 巻, 4 号
選択された号の論文の6件中1～6を表示しています
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Ryoji Shiraki, Hitoshi Sakai, Mikiya Endoh, Noriaki Kishima1987 年 21 巻 4 号 p. 139-148
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーExperiments on glassy rhyolite- and phenocrystic andesite-seawater interactions were carried out at 300°C and 1, 000b using Dickson-type gold bag equipments. Chemical reactions in rhyolite-seawater interaction proceeded very rapidly and a steady state was attained within about 48h. Andesite-seawater interaction, however, proceeded very slowly and a steady state was not attained within the run period of 7, 090h. Rhyolite and glass, augite and hypersthene in andesite were altered into smectite. Seawater lost most Mg2+ and SO42- and become acid Na-K-Ca-Cl-type solution through the reactions. The experimental result suggests that two stage alteration episodes existed in Kuroko-type mineralization. The present experimental solutions reproduced the chemical composition of a deep hot water from a bore hole drilled into andesitic geothermal area of southern Kyushu. However, shallow thermal waters discharging from andesitic volcanic rocks along some coastal areas of Japan cannot be explained as direct products of high-temperature interaction of seawater and fresh acid volcanic rocks.抄録全体を表示PDF形式でダウンロード (2808K) -
Zhenwei Qin, Fuji Yu, Jinsheng Yu1987 年 21 巻 4 号 p. 149-157
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーD/H ratios and H2O contents have been measured for 9 samples of alkaline granites from Kuiqi, Fuzhou and 11 samples of alkaline and monzonitic granites from Qingdao, both on the eastern coast of China. The δD values range between -99 ∼ -115‰ for the alkaline granite from Kuiqi with H2O contents of 0.08 ∼ 0.13 wt%. For Qingdao granitic complex, the alkaline granite exhibits a δD range of -116 ∼ -145 ‰ with H2O contents of 0.07 ∼ 0.15wt%, in contrast to -98 ∼ -104‰ and 0.16 ∼ 0.59wt%, respectively, for the δD and H2O contents of the monzonitic granite. The genetic correlations of the two alkaline granites with extensional fault belts, the miarolitic cavities disseminated in the granites and particularly the steep correlation of δD vs. H2O contents of the alkaline granites suggest that degassing may be a characteristic process during the magmatic stages of alkaline granites, leading to depletions of deuterium and water contents in the granites. It is proposed that the enrichment of deuterium in the vapor during magmatic degassing is due to the D/H isotopic fractionations among the hydrogen-bearing species in melts, i.e., H2O, OH-, H+ etc., in which H2O is the most D-enriched one.抄録全体を表示PDF形式でダウンロード (2431K) -
Shun Nakano, Takaaki Fukuoka, Shigeo Aramaki1987 年 21 巻 4 号 p. 159-172
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーAbundances of 16 trace elements including rare earths are determined by the instrumental neutron activation analysis for the Quaternary volcanic rocks of central Honshu, Japan. There is no systematic lateral variation along the Norikura volcanic chain except for the older part of Ontake volcano and Ueno volcano. The across-arc variation along the transverse through Yatsugatake-Norikura-Hakusan volcanoes does not reveal a regular increase in the incompatible element abundances away from the volcanic front. Based on the incompatible element abundances normalized to SiO2 = 50%, volcanoes in central Honshu are grouped into three, that is, Myoko and Kurohime (MK & KH), Yatsugatake (YT) and Norikura volcanic chain and Hakusan (NVC & HK) in increasing order. This variation can be explained by the difference in degree of partial melting and of the local enrichment of K and Rb in Myoko and Kurohime volcanoes.抄録全体を表示PDF形式でダウンロード (3609K) -
Kazuhiro Suzuki1987 年 21 巻 4 号 p. 173-182
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーThe distribution of U, Th and Pb is determined on an electron microprobe for zircon in the Naegi granite of the Late Cretaceous from Hirukawa, Gifu Prefecture, Japan. The UO2, ThO2 and PbO contents of zircon range from less than the detection limit (50ppm) to 3.45%, 2.46% and 360ppm, respectively. The Pb content of some portions in each grain is equivalent to what has been generated by the radioactive decay of co-existing U and Th since the granite crystallization, but other portions evidently show either deficient or excess Pb with respect to the U and Th contents. The granite has not undergone any thermal event after the intrusion. The Pb-deficiency and -excess arc explained in terms of Pb-loss and -gain owing to the migration of gaseous daughters (Rn) through radiation damage. The Rn atoms that entered into a network of radiation damage by recoil at the birth can move at random: they are adsorbed for a moment on the walls of radiation damage, and then re-emitted in random directions. Their residence time on the walls depends on the heat of adsorption which increases with increasing number of irregular sites on the walls, so that Rn atoms tends to decay on irregular walls as compared with smooth walls. This process disturbs the distribution of radiogenic Pb, and brings forth the enrichment and depletion of Pb with respect to the U and Th contents of zircon.抄録全体を表示PDF形式でダウンロード (2942K) -
Takeshi Ohba1987 年 21 巻 4 号 p. 183-186
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーThis paper describes an improved procedure for D/H and 18O/16O ratio analyses presented originally by Kishima and Sakai (1980). A sealed glass tube for the isotope exchange equilibration between water and CO2 gas was employed instead of a conventional container with a greased stopcock. The use of the sealed tube enabled us to handle 5 ∼ 6μmol of water for accurate and precise δ18O measurement, with precision of 0.42‰ (1 σn-1). However, for precise δD measurement more than 40μmol of water was required.抄録全体を表示PDF形式でダウンロード (1100K) -
P. K. Kuroda, Z. Z. Sheng1987 年 21 巻 4 号 p. 187-196
発行日: 1987年
公開日: 2008/04/08
ジャーナル フリーThe isotopic compositions of xenon found in some of the submarine pillow volcanic glasses from the East Pacific Rise (CYAMEX) are quite similar to those of the so-called CCFX xenon released from the carbonaceous chondrite Renazzo. The reasons for this similarity are explained in terms of the alteration of the isotopic composition of xenon in the solar system caused by a combined effect of mass-fractionation, spallation and neutron-capture processes.抄録全体を表示PDF形式でダウンロード (2592K)
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