The Journal of the Geological Society of Japan
Online ISSN : 1349-9963
Print ISSN : 0016-7630
ISSN-L : 0016-7630
Volume 60, Issue 700
Displaying 1-4 of 4 articles from this issue
  • Nobuo K0ZIMA
    1954 Volume 60 Issue 700 Pages 1-6
    Published: January 25, 1954
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    In the central part of the Miura Peninsula, the Hayama group, which uncomformably underlies the Miura group, is distributed in two areas, namely, the Akiya-Takeyama area and the Hayama-Kinugasa area., In the Akiya-Takeyama area, the group is divided into the following seven formations in discending order (3), (3') and (3") are the same horizon., (5) Kinugasa mudstone, (1700m+in thickness)., (4) Nakayama fine sandstone, (1100m±in thickness)., (3) Oyama tuffaceous sandstone, (1100m±in thickness); (3') Osawa sandston and conglomerate, (900m±); (3") Sakanodai tuff-breccia, (400m±in thickness)., (2) Hatadateyama alternation of sandstone and shale, (1000m± in thickness)., (1) Morito mudstone, (1400m+in thickness)., These formations are folded, and several masses of serpentine have been intruded along the three axes of the folds., In the Hayama-Kinugasa area, the group is divided into the following two formations in discending order., (2) Tateisi shale, (350m+in thickness)., (1) Takeyama siltstone, (1500m+in thickness)., These formations are monoclinic in structure, strike east, and dip about 60° north., Although no important fossils have been discovered in these formations, on the basis of stratigraphy, the group is thought to be Japanese lower Miocene (F1 in IKEBE'S Letter Nomination) in age., My paper on the Miura group will be published in this Journal in the near future.,
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  • Kenji KONISHI
    1954 Volume 60 Issue 700 Pages 7-17
    Published: January 25, 1954
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    The Shimozaisho alternation of limestones and clayslates is an unusual sedimentary mass located within the Hida gneiss terrain., The alternation is covered by later sediments and lavas; however, its relation to the Hida gneiss is indeterminable., Although the alternation of limestones and clayslates is both thermally and dynamically metamorphosed, some poorly preserved fossil corals and fusulines have been found in the Shimozaisho limestone, a member of the alternation., These fossils suggest Moscovian for the age of the limestone., The find of the Moscovian Fusulina Zone is a new discovery in the strata of the Hida Plateau., Because the Jurasso-Cretaceous Tetori group which overlies the Shimozaisho alternation is not metamorphosed, the alternation is thought to have been metamorphosed sometime between the late Paleozoic and early Mesozoic.,
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  • Toshio SUDO
    1954 Volume 60 Issue 700 Pages 18-27
    Published: January 25, 1954
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
  • Toshimasa TANAI, Atsuyuki MIZUNO
    1954 Volume 60 Issue 700 Pages 28-39
    Published: January 25, 1954
    Released on J-STAGE: April 11, 2008
    JOURNAL FREE ACCESS
    This paper discusses the following subjects concerning the Kumano group (Miocene, = Miyai series + Shimosato series + unnamed strata) in the vicinity of the Kumano coal field., (1) The Kumano group is divided into two formations, namely the Koguchi and Mitsuno formations, the former being characterized by a large quantity of siltstone and the latter by coarse quartzose sandstone; the group is further subdivided as follows., Hyoren member, (ss & st) 0yama member, (ss & st alt) Kowase member, (ss) Akagi member, (ss & st) Shiko member, (ss) Taniguchi member, (ss & st alt) Miyai coal-bearing member Wada member, (st) Taniguchi member, (ss & st alt) Wadagawa member, (st) Kamazuka member, (ss & st alt) Shikiya member, (st) Ohara member, (eg & ss) Mitsuno formation Koguchi formation Kumano group Kinan "group" (2) The strata of the Kumano group in this district have a general strike of north-south or N 20° and dip 15° to 40° east, except along the syncline in the northeastern part of the district., Many faults are present in the northern part but there are fewer to the south., The writers think that these structures had been made before the intrusions of the Kumano acidic igneous rocks., (3) The rock facies and the molluscan fossil-coenoses of the group suggest that the basin of deposition became smaller as a whole, especially after the deposition of the Koguchi formation, and accompanying the depoaition of coal., (4) From the field observations, the writers consider the so-called Eocene Shimosato series located on the southern coastal area as being the same age as the so-called Miyai series, though both are very different from each other in rock-facies and structure., However, the process which caused the differences remains unknown.,
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