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Volume 54 (1948)
- Issue 631-633 Pages 3･･･
- Issue 628-630 Pages 1･･･
Volume 54, Issue 628-630
Displaying 1-6 of 6 articles from this issue
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Sadakatu TANEDA1948 Volume 54 Issue 628-630 Pages 1-5
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe volcanoes in Japan belong to several volcanic zones, that is, the Chishima volcanic zone, the Nasu volcanic zone, the Fuji volcanic zone, the Ryukyu volcanic zone, etc., The each zone is composed of some volcanic chains arranged in echelon type., In this paper the date of volcanic activities on record was examined and the notable facts were pointed out, that is, (1) most volcanic zones in Japan began the eruption almost at the same time, rather periodically throughout the history, (2) generally saying the activity migrated from the inner chain in echelon arrangement to the outer one belonging to the same volcanic zone, and (3) there was a tendency that the activity spreaded from S to N in one volcanic zone., The facts in (2) and (3) mentioned are admitted easily in the Chishima and Nasu volcanic zones especially.,View full abstractDownload PDF (836K) -
Sadakatu TANEDA1948 Volume 54 Issue 628-630 Pages 6-12
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThere is urgent need for more accurate variation diagram of the optic properties with FeSiO3 content in the orthorhombic pyroxenes., The writer attempted to construct the diagram on the basis of the most credible date at present (as listed in the Table I) and obtained the rather successfull result as shown in the Fig., 1., The intensity of influence of Al2O3, CaO, Na2O, K2O, and TiO2 to the refractive index and optic angle was also discussed and estimated approximately as follows : Al2O3 (for Al replacing Mg) : 1% increases the refractive index about 0., 004-0., 007., Al2O3 (for Al replacing Si) : 1% increases it about 0., 002., When Na2O is rich (>0., 2%±), the influence of Al2O3 is much little., CaO (for Ca replacing Mg) : 1% decreases st about 0., 002., CaO (for Ca replacing S1) : 1% decreases it about 0, 002., Na2O : 1% decreases it about 0., 001-0, 01 K2O : 1% increases it about 0., 004., TiO2 : 1% increases it about 0., 008., Fe2O3 (as FeO) / Total FeO : 0., 1 decreases it about 0., 005., The factor decreasing the refractive index may increase the optic angle about X., The detailed discussion should be done refering to the studies on the mother rocks as well as the microcomponents.,View full abstractDownload PDF (936K) -
Sadakatu TANEDA1948 Volume 54 Issue 628-630 Pages 13-16
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe volcano Sakurajima began its latest eruption on 11th, March, 1946., At first it ejected the considerable amount of ash with some breccias and bombs, and then began the gush out of lava., The action with the effusion of lava was continued through the period from 13th, March to 24th, May, and the total amount of lava effused in this period reached to 130, 000, 000 cc., In this report was given the petrographic description on the new lava, the specimen of which was collected from the front of the lava flow, at 1 km., N., from the Kurokami village on 17 th, March, 1946., It is black and porous but comparatively compact, with some glassy lustre., It has phenocrysts and microphenocrysts of plagioclase (An55-83), hypersthene, augite and magnetite, scattering inthe dark glassy or cryptocrystalline groundmass., Optical constants of hypersthene and augite are shown as follows : Hypersthene: (-)2V=68°, 66°, 61°, 60°, 59°, 55°, β=1, 700-1., 704- Augite: (+)2V=55°, 50., 5°, 50°, β=1., 697-1., 704- The chemical composition was not determined, but SiO2 (61%) was measured by Assist., Prof., I., IWASAKI., At the end it may be said that the new lave is two-pyroxene andesite similar to the so called "the Taisho Lava (I)" belonging to the eruption of 1914.,View full abstractDownload PDF (634K) -
K. KAWADA, N. KANOMATA1948 Volume 54 Issue 628-630 Pages 17-18
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSTorinoko block mountain mainly consists of sandstone, shale and rarely conglomerate ; but its geological age is unknown, for fossils are very rare in these formations., We discovered a few Palaeozoic fossils of Brachiopoda and Foraminifera in limestone pebbles in the conglomerate taken from the older rock formation at Sarukubo, Senda valley, Yasato village, Naka-gun, Ibaragi Prefecture in 1944., According to H., Fujimoto, the Brachiopoda are of Martinia sp., and some of the Foraminifera are of Pachyphloia sp., and the others are of Schwagerina sp., ; and these fossils indicate to belong to the Permian period., Therefore the geological age of the older rock formation is considered to be post Permian period.,View full abstractDownload PDF (356K) -
Kunio KOBAYASI1948 Volume 54 Issue 628-630 Pages 19-24
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSLittle has been written about the geology of the Santyoku coal field except "Rep., Geol., Surv., Coal Field in Korea, Vol., 14, 1940"., During the period from 1942 to 1944, the present writer surveyed the Santyoku district., This is the summarized report of thi stratigraphy of the district., The Pre-Canbrian System is composed of orthogneiss and metagneiss., Tyosen System (from lower Canabrian to middle Ordovician) is divided into 9 groups of formations, some of which bear trilobites, branchiopods and cephalopods., The type of sedimentation correspouds to that of Girinkitu district., The system shows a large synclinal structure along an axis of NNE trend., Heian System (Koten Group, Carboniferous) contains many limestone layers but no distinct fossil has been found therein., Siragi Series (Cretaceous) consists of red conglomerate and tuffaceous formations., A non-marine deposit contains plant fossils., Santyoku-Group (upper Miocene) is a fan-shaped deltaic deposit., Its lower part consists of diatom earth and the upper of gravel and sand., The former contains plants of Miocene type and non-marine shells, by which the age of the formation is determined., Two conspicuous igneous activities are found ; one in the Pre-Cambrian and the other in the Bukko kuzian epoch., The tectonic movement in the Taiho phase recorded no remarkable structures in the district and the faults of NNE trend were formed before the deposition of Santyoku Group.,View full abstractDownload PDF (1008K) -
Tosio SUDO1948 Volume 54 Issue 628-630 Pages 25-30
Published: July 20, 1948
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSMain minerals found in alterated country rocks of ore deposits are fine clay minerals which are accurately invesitigated by X-ray powder patterns as well known., In this report, the writer summarized up X-ray powder photographs already published and also taken in Japan, and showed the chracteristic powder lines of each clry mineral., The date are important to carry on the fundamental studies on alteratin of country rocks of ore deposits., The chracteristic properties of each powder photograph of each clay mineral are clearly shown by (001) reflections.,View full abstractDownload PDF (849K)
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