巻号一覧
6 巻 (1972 - 1973)
- 4 号 p. 151-
- 3 号 p. 105-
- 2 号 p. 43-
- 1 号 p. 1-
6 巻, 3 号
選択された号の論文の4件中1～4を表示しています
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Akira Miyazaki, Kazuo Sato, Nobufusa Saito1973 年 6 巻 3 号 p. 105-116
発行日: 1973年
公開日: 2008/04/08
ジャーナル フリーThe isotopic compositions of lead and the approximate concentrations of lead and uranium were determined for some gneisses and Paleozoic sandstones from the Hida metamorphic terrain, Japan. All the Hida gneisses studied have similar 206Pb/204Pb and 207Pb/204Pb ratios. The lead in these rocks is significantly more radiogenic than that from the Precambrian metamorphic complex in the eastern part of Asian continent. This difference suggests that these two rock systems developed in different geochemical environments. The lead of the sedimentary rocks from the Hida metamorphic terrain shows a large variation in 206Pb/204Pb and 207Pb/204Pb ratios, and generally appears more radiogenic than that of the gneisses. These isotopic data indicate some genetic correlation between the metamorphic and sedimentary rocks but are not sufficient to demonstrate that these sedimentary rocks were the original materials of the Hida metamorphic rocks. The lead isotopic data for the sedimentary rocks can be interpreted by means of a two-stage evolutional model. The time of formation of the second evolution system is estimated to be (2, 300 ± 350)m.y. This value may be related to some Precambrian igneous activity in the present site of the Japanese Islands.抄録全体を表示PDF形式でダウンロード (6111K) -
M. Michael Murray, John J. W. Rogers1973 年 6 巻 3 号 p. 117-130
発行日: 1973年
公開日: 2008/04/08
ジャーナル フリーThe abundances of rubidium and strontium have been determined in potassium feldspar separates and some whole rock samples from two Precambrian batholiths, the San Isabel batholith of the Wet Mountains, Colorado, U.S.A., and the Buchanan massif (Lone Grove pluton) of central Texas, U.S.A. Absolute abundances of the two elements in the feldspars vary widely, but the Rb/Sr ratio is relatively constant within mapped zones or facies. Selective precipitation of potassium over rubidium into early-crystallizing potassium feldspar leaves late-stage magmatic fluids enriched in rubidium and thus causes the absolute rubidium contents and the Rb/Sr ratios of feldspars and whole rocks to be highly dependent on the activity of volatiles. Escape of volatile-rich, end-stage fluids is apparently responsible for decrease in Rb/Sr ratios toward later-crystallizing rocks. The preservation of widely different Rb/Sr ratios in minerals in different facies of a comagmatic rock assemblage provides, through later partial melting, one method of generating non-zero initial apparent isochrons in whole-rock strontium isotope studies of igneous suites.抄録全体を表示PDF形式でダウンロード (6995K) -
Setsuko Wada, Nobuhide Kokubu1973 年 6 巻 3 号 p. 131-139
発行日: 1973年
公開日: 2008/04/08
ジャーナル フリーAtmospheric salt samples were collected on meshes over the sea, from which water soluble fractions were separated to determine Cl, Na, K, Mg, Ca and F. The contribution of sea spray and materials of continental origin to the atmospheric salt was discussed from the data obtained. In the light of the initial aim of the present investigation, some criticism was made on the way of approach and the methods employed including their check for the future extention of the present investigation.抄録全体を表示PDF形式でダウンロード (3861K) -
Chemical composition of ore-forming solution responsible for the Kuroko type mineralization in JapanYoshimichi Kajiwara1973 年 6 巻 3 号 p. 141-149
発行日: 1973年
公開日: 2008/04/08
ジャーナル フリーOn the basis of available mineralogical and geochemical data for the Kuroko type deposits in. Japan, an attempt has been made to calculate the concentrations of some elements in the ore-forming solution responsible for this type of mineralization. The result reveals that the abundances of elements in the hydrothermal system are fairly close to those observed in the present-day ocean water.抄録全体を表示PDF形式でダウンロード (4461K)
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