Abnormal winter weathers from 1962 to 63 remined us of 9-year periodicity which has been found in the change of winter temperature and snow amount in the northern part of Japan. The reality of 9-year periodidity, however, is not accepted fully by meteorologists owing to the insuffuciency of the statistical significant tests, and the lack of physical explanation on it. In this paper, the existence of 9-year periodicity has been shown by harmonic analysis with quite small statistical risk in the change of January temperature of Tokyo and number of typhoon hit in a year. The present author suggests that the periodicity may be explained by long periodic change of the tidal force due to the following reasons. (1) 9-year periodicity is one of main periodicity in the change of tidal force. (2) Recent statistical investigations prove the existence of semisynodic change of the rainy days in America and Australia.
A new idea is here introduced for elucidation of a problem, left unsolved for a long time, concerning three geological features characterizing Southwest Japan. 1. The Ryoke metamorphics have their axial zone of gneisses and associated granitic rocks close to the Median Dislocation Line of Southwest Japan along its northern side. The grade of metamorphism decreases gradually northward through the inner or north wing of various schists and hornfelses finally to non-metamorphosed Palaeozoic rocks. In contrary, there is no trace of its outer or south wing preserved at least along the greater part of the Median Dislocation Line. 2. In the Outer Zone of Sikoku, conglomerates in various Mesozoic formations are often stated to contain, sometimes even profusely, water-worn gravels of the rocks similar to the Ryoke metamorphics and associated granitic rocks, in strong contrast to the total absence of gravels of the rocks similar to the Nagatoro metamorphics, in spite of the present geographical situation of the sites of the conglomerates lying much nearer to the terrain of the Nagatoro metamorphics than to that of the Ryoke. 3. Likewise, very attractive is the total absence of detritus of the Nagatoro metamorphics and the abundance of non-metamorphosed Palaeozoic rocks, Ryoke metamorphics and associated granitic rocks in the Upper Cretaceous Izumi sandstone, which occupies a narrow terrain be tween the northern terrain of the Ryoke metamorphics and the southern terrain of the Nagatoro metamorphics. All these geological accounts can easily be explained, the writer believes, only by assuming that the outer wing of the Ryoke metamorphics once occupied a much higher level above the Nagatoro metamorphics, with a fairly wide intervention of feebly and non-metamorphosed Palaeozoic rocks, in the present terrain of the Nagatoro metamorphics.
The writer carried out some investigation in order to estimate the amount of groundwater discharge through the section of Mukawa River valley near Kawanishi intake-dam, Mukawa Town in Hokkaido. He surveyed the geology of the flood plain by means of electric resistivity methods using apparatus of the Electro-Technical Laboratory type and checked the result by test borings. The Mukawa River valley is underlaid with a Tertiary formation (most of it is conglomerate), diluvial and alluvial deposits ; the latter two are composed of loose sand and gravel.The diluvial and alluvial deposits are very productive aquifers. The writer found the existence of an underground river valley, with a maximum depth of some 30 meters and also found there a buried flat surface of the Tertiary formation (conglomerate) lying at the depth of 5-8 meters under the surface. This buried surface is considered to be an old buried terrace surface. The deposits in the river valley are divided into two parts, the upper and the lower. The sand and gravel of the upper is rather coarser than that of the lower. The boundary of them lies 5-8 meters deep under the surface, the same position of the buried terrace surface. Apparently, the upper is an alluvial deposit, but the lower is a buried deposit in the underground river valley. It may be possible to think that the lower is a diluvial deposit. From the groundwater contour map obtained from the observation of 18 wells, it was found that the groundwater generally furnished the river water in the survey area. The writer calculated the gradient of the groundwater flow and evaluated the permiability coefficient by an aquifer test. The amount of groundwater discharge through the valley section “D” is estimated as 0.0156 m3/sec.
In the summer of 1962 the authors had some limnological observations in Lake Kizaki using an echo sounding instrument which has rarely been used in Japanese lakes though it has many excellent characteristics. The authors made a map of basin topography and, comparing this map with an old one which was drawn by Dr. Tanaka by means of lead in 1930, some remarkable differences are pointed out as follows : 1) The area of the bottom plain of the lake is larger and deeper, and microtopography of the basin seems to be rather simple these are thought to be due to the sedimentation during late 30 years and the difference of the methods. 2) The delta at the northern end of the lake formed with the deposits of an inflowing river seems to have developed westward a little. 3) The lake shelves were observed in the depth of 10-15 m at the eastern part and 5-10 mat the northern part of the lake. The distribution of the plankton layer was observed also with this instrument as is shown in Fig. 2 the area where the distribution of plankton is dense coincides with the area of high transparency. Finally, this instrument is useful not only for the observations mentioned above but for the research of thermal stratification, tracing of inflowing water, etc. The authors believe it will be used increasingly in limnological researches.
Common geological features of the known kimberlite-occurring regions in the continents are briefly described with special notice to certain tectonic processes that seem to be linked to the eruption of kimberlites. Some investigators suppose that kimberlite magma originated in the peridotite layer just below the Mohorovicic discontinuity. Judging, however, from the tectonic processes prior to the eruption of kimberlites in most regions and the structural model concerning to the crust and the upper mantle supported by the writer, sources of kimberlites might be in more deeper part of the mantle than the peridotite layer.