All issues
Volume 24 (1970)
- Issue 6 Pages 191-
- Issue 5 Pages 151-
- Issue 4 Pages 115-
- Issue 3 Pages 79-
- Issue 2 Pages 43-
- Issue 1 Pages 1-
Volume 24, Issue 6
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
-
with special reference to sedimentary environment of the basal fine tuff bed(Collaboration Research News)Yamagata Cenozoic ResearchGroupArticle type: Article
1970 Volume 24 Issue 6 Pages 191-192
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (322K) -
Keizo FUJIIArticle type: Article
1970 Volume 24 Issue 6 Pages 193-200
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe stress changes which are associated with the crustal deformation have hitherto been studied by geophysists. For example, the stress changes have been calculated from such factors as the maximum displacement on the fault plane, the depth of the fault and others based on the theoretical treatment on the strike slip fault. Geologically it is believed that the thickness variation reflects the variation of the amount of vertical displacement of the crustal deformation. Numerous key beds of tuff are known in the Otadai formation of Kazusa group in the Boso Peninsula. Recent study by HIRAYAMA and SUZUKI (1968) revealed in detail the thickness variation between the Key bed O7 and K3 among above. According to them an elliptical sedimentary basin were developed there, its longer axis is 60 km and shorter axis is 30 km in length. The thickness of the strata between O7 and K3 is 6.5 m in the central part of the ellipse but decreases toward the margins. Present writer considered that the thickness variation were caused bythe crustal deformation. The writer (1970) calculated the stress changes, on the assumption that the thickness variation was equal to the variation of the vertical displacement whic was associated with the vertical force exerted under the earth crust. In this paper, the writer considered that the same thickness variation was caused by the crustal deformation as the result of the horizontal tensile force, and calculated the tensile force by finite element method. The elastic model is as follows. The writer assumed that the elastic rectangular plate (60 km in length and 30 km in height) was laid on the semiinfinite plate. Two cases were assumed. On one of the cases, the one end of the plate is fixed, the lowest part of the plate is moved laterally and the other end is moved laterally by uniform distributed tensile force. On the other cases, the small semicircle is made in the middle of the lowest part in the elastic rectangular plate, and is occupied by liquid, and other conditions are the same as the above case. Comparing with the magnitude of the vertical force by which the sedimentary basin was supposed to be caused, the result shows that the magnitude of the horizontal tensile force by which the sedimentary basin was supposed to be caused is only one-twentieth.View full abstractDownload PDF (839K) -
Tsuyoshi FUJITA, Hiroshi KIMURAArticle type: Article
1970 Volume 24 Issue 6 Pages 201-207
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe building process of the Myoko volcano has been clarified by Myoko Research group in 1969. Then, plant remains were collected from the mud flow in the northern foot area in consequence of the breaking on the northern outside slope of the somma (mud II) for the determination of the absolute age by the use of 14C, and the numerical valve of 17,900±450 Y.B.P. years are resulted. In this paper, the analysis of the assemblage of fossil diatom found in eleven samples from the former peat deposit (30 cm in thickness) were treated, and 51 species of 21 genera were totally identified. The dominant and common species in them are Achnanthes lanceolata, Diploneis elliptica, Diatoma vulgaris, Meridion circulare Diatomella balfouriana, and all species showing low frequency in these assemblage may be characterized by rheophilious forms, which have ecological optimum in the running water and distribute comparatively in low water-temprature. From these results, the peat sediment examined are inferred to have been settled at the bottom of the lake or marsh of the low mountainland.View full abstractDownload PDF (1624K) -
The Research of Younger Cenozoic Strata in Kinki District, Part 17Nishiyama Research Group, Earth Science Club of Katsura High SchoolArticle type: Article
1970 Volume 24 Issue 6 Pages 208-221
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe stratigraphy of the Osaka Group in surveied area is as follows; [table] This stratigraphy is well accorded with that of the other hills which made of the Osaka Group; for example, Senriyama,Ibaraki and Hirakata Hills. Tomistoma sp. and many plant fossils yielded in this area as shown in Table 2. The paleocurrent directions deduced from cross beddings and inclination of gravels were obtained. The results are summarized in Figs. 9 and 10. Paleocurrent directions are clearly divided into two groups ; that is, from northeast to southwest and from southeast to northwest. The former may be products of the ancient river Akuta and the latter may be from the ancient river Yodo. These two directions are found at same cliff in several places.View full abstractDownload PDF (1599K) -
Susumu NISHIMURA, Sadao SASAJIMAArticle type: Article
1970 Volume 24 Issue 6 Pages 222-224
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSThe fission-track technique is briefly described. Fission-track ages were obtained on six zircons, two hornblendes, one anthophilite and one apatite from eight ash-layers of the Plio-Pleistocene Series in Kinki district, Japan. They are compared with other paleomagnetic dates measured on these rocks. In all cases the fission-track age within its expected error agrees with the other ages.View full abstractDownload PDF (317K) -
Limestone caves and river terraces in Atetsu plateau, western JapanAtetsu Research GroupArticle type: Article
1970 Volume 24 Issue 6 Pages 225-227
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (378K) -
14C-Age of the Quaternary Deposits in Japan (60)Saburo AKAGI, Kiyoharu HOSHIMI, Yoshinori TOYOSHIMAArticle type: Article
1970 Volume 24 Issue 6 Pages 230-231
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (262K) -
14C Age of the Quaternary Deposits in Japan (61)Hideyoshi SEGAWGArticle type: Article
1970 Volume 24 Issue 6 Pages 231-232
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (304K) -
14C-Age of the Quaternary Deposits in Japan (62)Shoji OIKE, Hajime TAKAHASHIArticle type: Article
1970 Volume 24 Issue 6 Pages 232-
Published: 1970
Released on J-STAGE: July 26, 2017
JOURNAL OPEN ACCESSDownload PDF (191K)
- |<
- <
- 1
- >
- >|