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Volume 59, Issue 690
Displaying 1-8 of 8 articles from this issue
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Teruhiko SAMESHIMA1953 Volume 59 Issue 690 Pages 75-78
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
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Atsushi MATSUBARA1953 Volume 59 Issue 690 Pages 79-87
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
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T. SAMESHIMA, R. MINAMI1953 Volume 59 Issue 690 Pages 87
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
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MITSUE KOIZUMI, RYOITI KIRIYAMA1953 Volume 59 Issue 690 Pages 88
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
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Arata SUGIMURA1953 Volume 59 Issue 690 Pages 89-91
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe Quaternary terrace (figure 5) extends 8 km along the River Dozangawa and is composed of a bed of pumice of hypersthene-brown hornblende-quartz-plagioclase (andesine and labradorite)-glass-dacite., In parts, it rests upon a flow of hornblende-biotite-quartz-plagioclase (andesine)-glass-dacite., The characteristics of geomorphological (figure 1) together with geololgical feature (figures 2, 3, and 4) of the bed suggest it to be nothing but a pumice flow from the definite position near the southwestern end of the terrace, where a pan-shaped depression, two kilometers in diameter, is now observed (figure 1)., The depression may exhibit a small caldera closely related to the pumice, the volume of depression being estimated as 0., 8 km3, while that of the pumice flow 1., 4 km3.,View full abstractDownload PDF (885K) -
Yo NARUSE, Arata SUGIMURA1953 Volume 59 Issue 690 Pages 92
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
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Yoshiro TAI1953 Volume 59 Issue 690 Pages 93-98
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSIn the present paper, the following facts are described in detail, continued from the preceding paper., (1) In the area occur the Koura sandstone member of the lowest formation and the middle formation, the Furue formation, of the Shinji group., The Furue formation consists of three members, the Josoji shale, the Ushikiri alternation and the Furue mudstone., The relations of these members are conformab1e, except for the relation between the Josoji shale member and the Ushikiri alternation member, which are in contact with each other by a fault., In these members are found a few plant leaves and several smaller foraminifers, such as Dryophyllum dewalquer ? SAP., Salix Sp., etc., from the Koura sandstone member, Cyclammina, cf., cancellata BRADY from the Josoji shale member and Martinottiella, communis (d'ORBIGNY), Cyclammina incisa (STACHE), C., japonica, ASANO, etc., from the Furue mudstone member., The detailed study of smaller foraminifers is now in progress by the writer., (2) As described in the preceding paper, the eastern area is characterized by "positive" structural forms, such as anticlines and domes., In contrast with the eastern area, the present area is characterized by "negative" structural forms, such as synclines and basins, which are related to the hinge faults, extending nearly E-W.,View full abstractDownload PDF (832K) -
Motoki EGUCHI, Rikii SHOJI1953 Volume 59 Issue 690 Pages 99-109
Published: March 25, 1953
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSTo develop a new colliery, we have restudied the geological structure of the Joban Coal-field in detail, employing for this purpose a topographical map exceeding 1/10000 in scale., The previously accepted formations have been stubdivided for the purpose., The Ishiki bed of the late Dr., S., Tokunaga (including the Shiramizu coal bearing bed and Iwaki sandstone bed of tlae late Dr., Watanabe) was subdivided into several Cycles, each representing cyclical sedimentation., Each "Cycle (Rinneso)" is treated here as a formational unit because of being mapable in our geological map., Each unit is named according to stratigraphic terminology., The coal bearing or terrigenous formation is composed of many thin cyclical beds, while pure marine formations form large scaled cyclical- beds (Megacycle) as shown by the Asagai and Shirasaka formations of authors, for the latter case the lithological characteristics were the basis for treating it as a formation unit., Each cyclical formation is composed of the following rocks; from base to top, Conglomerate or coarse sandstone, Medium or fine sandstone, Sandy shale or shale sometimes with coal seams., Where the cyclical formation is too thin for mapping, two or three such cycles are combined and mapped in the same colour for conveniense., The stratigraphical sequence of the formation in the present studied area is as follows; Quaternary Alluvial deposits unconformity Terrace deposits unconformity Plateau deposits unconformity Tertiary Pliocene Miocene Oligocene Pre-Tertiary Taga Group Yungagaya Group Shiramizu Group Hanakawa formation Tempizan formation Isohara formation Futatsuzima formation unconformity Kozawa formation Ashigaya formation Kunugidaira formation unconformity Shirasaka formation Upper Asagai formation Lower Asagai formation Sekiya cycle Nemoto cycle Kisara cycle Nakahira cycle Maehanzo cycle Upper Yamashita cycle Lower Yamashita cycle Hikitorizawa cycle Kurumaoki cycle Azuhata cycle unconformity Basement complex In the course of the study we have recognized the following two important facts: (1) the number of cycles in the Hanakawa formation (Igarashi, 1945, M., S., ) differs in each district in the Joban coal field, in spite of the fact that the above mentioned megacycle can be trace throughout., In other wards 1 megacycle can be trace in all of the following districts while only 21 cycles occur in the Isohara districts, 24 cycles in the Yumoto district and only 8 cycles in the Futaba district., (2) In general, the number of cycle in the coal sedimentation has been father traced successively over this region except incomplete one, though the sedimentary facies in the Hanakawa formation is variable laterally., The development of different cycles together with the prersisting of the megacycle in the mentioned districts affors us reliable data for coal exploitation and exploration in the Joban coal field., Employing the relation between coal beds and cyclic sedimentation, we have been able to bring forth data which would not have been gained by previous methods.,View full abstractDownload PDF (1453K)
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