地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
91 巻 , 1 号
選択された号の論文の6件中1~6を表示しています
  • 早津 賢二, 新井 房夫, 白井 亨
    1982 年 91 巻 1 号 p. 1-16
    発行日: 1982/02/25
    公開日: 2010/02/25
    ジャーナル フリー
    The late Pleistocene Series in the Takada plain, Niigata prefecture, central Japan is represented by constituents of the “Middle Terrace” called the Hirayama Terrace and the “Ancient Dune (Old Dune)”. The Hirayama Terrace, consisting of the Hirayama Formation, is distributed around the Takada plain, and the Ancient Dune, consisting of the Katamachi Sand bed, is distributed along the coast of the Japan sea from Joetsu to Kakizaki (Fig. 1).
    Many works have been published about the Hirayama Formation and the Katamachi Sand bed, but there are some problems on their formation ages and sedimental environments remaining unsolved. Generally, the Middle Terrace and the Ancient Dune are important for the consideration of the late Pleistocene geohistory in Japan. In this study, the writers try to determine the formation ages of the Middle Terrace and the Ancient Dune in this district. Sedimentology of their constituents will be discussed in detail in the next paper.
    Tephrochronological approach is usually effective for regional geologic chronology. Five dated marker tephra layers were found out in this district. They are Aira Tn Ash (AT) (21, 000-22, 000 y. B. P.), Daisen Kurayoshi Pumice (DKP) (45, 000-47, 000 y. B. P.), Katamachi Pumice (KtP) (65, 000-75, 000 y. B. P.), Hanabusa Pumice (HB) (approximately 100, 000 y. B. P.), and Kamitaru Pumice (KT) (130, 000-150, 000 y. B. P.). The Hanabusa Pumice and the Kamitaru Pumice are eruptives respectively from Myoko and Iizuna volcanoes, and the others have their source in the volcanoes far away from the Myoko volcano group. From the stratigraphic relationships to these marker tephra layers (Fig. 3), the chronology of the Hirayama Terrace, the Ainokaze Terrace heigher than the Hirayama Terrace, and the Ancient Dune is resulted as follows..
    1). The Kamitaru Pumice layer (KT) lies just above the Ainokaze Formation at Haizuka west of Joetsu city. From this fact, The Ainokaze Terrace plain, a part at least, is estimated to have been formed about 130, 000-150, 000 y. B. P.,
    2). The Hirayama Formation interbeds the Hanabusa Pumice layer (HB) within the uppermost part at the former type locality, Hirayama west of Joetsu city, and therefore the Hirayama Terrace plain may be formed about 100, 000 y. B. P..
    3). The upper part of the the Katamachi Sand bed includes the Katamachi Pumice layer (KtP) (Fig. 4), and is covered with the Daisen Kurayoshi Pumice (DKP) and the Aira Tn Ash (AT). The lower part is considered to have almost same age as the Hirayama Formation judging from their stratigraphic relation and sedimental environment. Accordingly, the Ancient Dune in the Takada plain is estimated to have been formed during the period from approximately 100, 000 y. B. P. to 50, 000 y. B. P.. This period corresponds with time of the marine regression which followed the Shimosueyoshi transgression.
  • 江川 良武
    1982 年 91 巻 1 号 p. 17-29
    発行日: 1982/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    The joints at the surveyed area develop nearly parallel to the ground surface, and their number decreases with the depth, so that these can be regarded as sheeting joints. The joint pattern and its rock control are investigated in detail at excavated tunnels, and conclusions are as follows.
    1) The sheeting joints are caused by the expansion and buckling of rock mass, either due to stress release or chemical weathering.
    2) The sheeting joints by chemical weathering are superimposed on the joints by stress release, and the former are steeper in gradient, closer in spacing and shallwer in depth than the latter.
    3) The difference of rock expansion by stress release is also found at rock type boundary, so that the intensity and orientation of sheeting joints is complicated where the slope is composed of different type of rock mass.
    4) The sheeting joints develope in the rock mass of which qu is more than 200 kg/cm2.
    5) The rate of joint development is in the order of 1 meter deep per 1000 years.
    6) The process of chemical weathering is accelerated by the water infiltration through the preexisting joints of sheeting.
    7) Unconformity is found between joint pattern and estimated gravity induced stress field, so that no gravity contributes to sheeting joint development.
  • 谷内 達
    1982 年 91 巻 1 号 p. 30-50
    発行日: 1982/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    One of the most important aspects of the mining activities in remote Australia since the 1960 's is large-scale infrastructure development by mining companies. This paper studies various types of infrastructure projects associated with the mining activities, from a viewpoint of development stages in terms of remoteness.
    Three study areas are selected; Pilbara region, Kalgoorlie region and Central Queensland, in order of remoteness. Mining railways and mining towns in the study areas are classified into three types, according to the extent of financial contribution by the mining companies.
    The railways of the first type are the iron are railways in Pilbara region. They are constructed, owned, operated and exclusively used by the mining companies. The railways of the second type are the coal railways in Central Queensland. They are constructed or upgraded, owned and operated by the government as a part of the State railway system, but are fully financed and almost exclusively used by the mining companies. The railways of the third type are the nickel railways in Kalgoorlie region. They are constructed and upgraded, owned and operated by the government, but are partly financed by the mining companies.
    The towns of the first type are the iron are mining towns in Pilbara region. They are company towns, which are constructed and managed by the mining companies. The towns of the second type are quasi-company towns, with a minor role of the government. Dampier and Wickham in Pilbara region and Kambalda near Kalgoorlie fall into this category. The towns of the third type are open towns, which are constructed and managed mainly by the governments with financial contribution by the mining companies. Port Hedland and Karratha in Pilbara region and the coal mining towns in Central Queensland fall into this category.
    These different types of infrastructure development can be interpreted as a reflection of different stages of regional development; the more developed, the less involved by mining companies. The idea is tested and supported by the historical cases in Mount Isa.
    One of the significant modifications of the development process mentioned above is an influence of the government policies, where higher priorities are given to more local participation in order to discourage influences of overseas capital, and to more local processing for the more value-added within the State or national economy. The reversed order of railway types against the general order of remoteness between Kalgoorlie region and Central Queensland can be partly explained by this point.
    A case study in this paper suggests that, from a viewpoint of regional development, infrastructure should not be simply defined by physical or institutional forms, but should be identified by examining actual functions. This functional concept of infrastructure would be useful for identifying the role of mining activities in regional development, especially in remote Australia.
  • 市川 正巳
    1982 年 91 巻 1 号 p. 51-62
    発行日: 1982/02/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 宮久 三千年
    1982 年 91 巻 1 号 p. 63-64
    発行日: 1982/02/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 吉岡 慎一
    1982 年 91 巻 1 号 p. Plate1-Plate2
    発行日: 1982/02/25
    公開日: 2009/11/12
    ジャーナル フリー
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