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Volume 10 (1970)
- Issue 3-4 Pages 79-
- Issue 2 Pages 39-
- Issue 1 Pages 1-
Volume 10, Issue 3-4
Displaying 1-5 of 5 articles from this issue
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Bunkichi OKINO1970 Volume 10 Issue 3-4 Pages 79-88
Published: November 15, 1970
Released on J-STAGE: September 20, 2011
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Mitsuo SATO1970 Volume 10 Issue 3-4 Pages 89-101
Published: November 15, 1970
Released on J-STAGE: September 20, 2011
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Minoru UTADA, Hideo MINATO1970 Volume 10 Issue 3-4 Pages 102-109
Published: November 15, 1970
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSSeveral sheets of intensely montmorillonitized andesite are inserted into the Miocene sediments around Koriyama-machi, Kagoshima Prefecture. They consist mainly of plagioclase phenocryst, montmorillonitized groundmass and a number of opal druse. As result of the observation under the microscope, the X-ray analysis and the chemical analysis, it is concluded that opal druses may have been formed by the precipitation of excess silica accompanying montmorillonitization of groundmass in secondary voids after pyroxine phenocryst. Most of opal druses are composed of the peripheral part, the horizontally precipitated part and the central void. And the inclination of the surface of horizontally precipitated opal is almost zero, though that of the sediments exceeds 10°. Then, this fact may suggest that the precipitation of opal may have lasted after the stage of main tectonic movement in this area.View full abstractDownload PDF (11582K) -
Toshio NEGISHI1970 Volume 10 Issue 3-4 Pages 110-116
Published: November 15, 1970
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSTwo different occurrences of laumontite are found at Kozawa, Iwanai-district, Hokkaido. One is the altered materials of volcanic glasses of Miocene green tuffs. Another is its concentration on the surface of the specimen. The latter laumontite is the pure material, and its structural formulae as follows,
(Ca3.128Mg0.055Na0.622K0.183)(Al6.95 FeIII0.073) Si16.939.O4813.260 H2O.
The chemical composition agrees well with the druze-type laumontites of the igneous rocks, but Na2O is slightly abundant. The cation exchange capacity by Shollenberger's method is less than 10 m. e./100 g. It shows that his method is not suitable to measure the C. E. C. of laumontite.
For the purpose of the estimation of the quantity of laumontite involved in the specimen, X-ray intensity method and chemical composition method have been applied. The former result is 19% and the latter 25.05%.
Clinoptilolite-tuff and mordenite-tuff were found near the laumontite-tuffs. No regulations were recognized in their distribution. It is probable that the genesis of laumontite is not by the diagenesis or the low-grade metamorphism, but by the local metamorphism (alteration) by the ore-solution and the like.View full abstractDownload PDF (2996K) -
Keiichi WATAHIKI1970 Volume 10 Issue 3-4 Pages 117-123
Published: November 15, 1970
Released on J-STAGE: September 20, 2011
JOURNAL FREE ACCESSIn order to investigate the character of compacted cohesive soil, a series of cyclic compression tests was performed. And the volume changes of specimens also measured.
The following results are obtained.
1) The cyclic compression tests are very useful to denote the failure process of cohesive soils. 2) The volume change character is closely conected with the following factors which indicate the change of soil structure.
Factors; Ene, Enl, Enp, εe, εp, εe/εt, dδ/dε.
3) The pseudo-elastic area on εe-εp curve, the uncontinuous point on (εe/εt)-εp curve and thebranching point of Ene-εp curve and Enl-ep curve show the sudden change of structure of soil.View full abstractDownload PDF (805K)
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