地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
98 巻 , 1 号
選択された号の論文の8件中1~8を表示しています
  • 大森 博雄, 柳町 治
    1989 年 98 巻 1 号 p. 1-18
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    To estimate palaeotemperature from the altitude of past vegetation zone compared with the present one requires the assumption that a vegetation zone is controlled by thermal condition. Since the lower limit of Pinus pumila zone occupying the highest zone of vegetation in the Japanese mountains is a marked boundary separating vegetation types and geomorphological processes, its physical conditions such as temperature, snow, wind and landforms have been examined. Recently, some researches have pointed that the altitude of the lower limit of Pinus pumila zone in Hokkaido, Japan, is dependent not on thermal condition, but on the factors reflecting the “top phenomenon” such as the winter season's north-westerly wind increasing in velocity with altitude and the surfacial condition of landform peculiar to the around summit of mountain. This suggests that the assumption for the estimation of palaeotemperature is not valid and the method using the lower limit of Pinus pumila zone as an indicator of temperature is not adequate.
    The present authors re-calculate the distributions of the relative altitude from summit level of mountain, the altitude above sea level, the warmth index, the mean temperature, annual, winter (Jan. Feb.) and summer (Jul. Aug.), for the lower limit of Pinus pumila zone and the upper and lower limits of Betula ermanii zone occupying the altitudinal zone just below the Pinus pumila zone in Hokkaido, compare their degree of dispersion of distribution, and re-examine the thermal conditions of the vegetation zones.
    Concerning the lower limit of Pinus pumila zone, the ratio of the range of the distribution of relative altitude from summit level to the range of the distribution of surface altitude of the whole area of Hokkaido is calculated to be 0.44 (1019m/2290m). In the same manner, for the range of the distribution of altitude above sea level, the ratio is 0.41 (950m/2290m). On the other hand, the ratio of range of the distribution of warmth index of the lower limit of Pinus pumila zone to the range of the distribution of warmth index for the whole area of Hokkaido shows 0.28 (16.8month·°C/59.2month·°C).In the same manner, for the range of the distribution of mean annual temperature, the ratio is 0.32 (4.7°C/14.7°C). Then, the degree of dispersion of the distribution of relative altitude from summit level is statistically evaluated to be larger than those of the distributions of thermal conditions. The same results are obtained for the upper and lower limits of Betula ermanii zone. This means that boundaries of vertical vegetation zones examined depend on thermal condition, showing the validity of the method estimating the palaeotemperature based on the changes in altitude of vegetation zone.
    The thermal conditions of the boundaries of vertical vegetation zones in Hokkaido can be expressed by any indices of warmth index, mean annual temperature, mean winter temperature and mean summer temperature with almost the same errors. But the mean summer temperature is superior to the others, since its standard deviation of distribution is the smallest among them. The mean summer temperature shows 14.7°C for both the lower limit of Pinus pumila zone and the upper limit of Betula ermanii zone, and 16.3°C for the lower limit of Betula ermanii zone. Their standard deviations are 1.1-1.2°C, showing that the boundaries of vertical vgetation zones examined are restricted to narrow thermal zone.
  • 浜島 良吉, 小出 仁, 川井 忠彦
    1989 年 98 巻 1 号 p. 19-33
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    The precise evaluation of heat transfer and, groundwater migration in fractured rocks is the key problem for the geological disposal of nuclear waste, energy extraction from hot dry rocks and underground storage of LPG. The stress state affect the heat transfer and groundwater migration due to the opening or closing of fractures in rock mass.
    The numerical method for coupled analysis of stress-heat-water-fractures is to be developed for the estimation of heat transfer and groundwater flow in the earth' crust.
    The Rigid-Body-Spring Model (RBSM) has been recently developed to simulate effectively the deformation and fracturing of jointed rock mass. The direct discretization through the conservation law is proposed for the numerical analysis of heat transfer and water flow coupled with the analysis of stress propagation in the jointed rock mass by the RBSM. The RBSM can be considered as a discrete model to fulfill the conservation law in the stress analysis.
    The numerical simulation of heat and fluid migration coupled with fracture propagation was applied for the performance assessment of underground oil and LPG storage.
  • 小林 貞一
    1989 年 98 巻 1 号 p. 34-48
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    In Japan 14 species in 21 genera of Carboniferous trilobites were known in 1980 and 22 species in 11 genera of the Permian ones in 1984. Adding a few species described since then, the Permo-Carboniferous trilobites of Japan total about 70 species at present. They are described from 18 horizons, namely 11 and 7 horizons respectively for the Carboniferous and Permian ones. They are compared with the faunas of the Mongolian geosyncline, Hwangho and Yangtze basins and Southeast Asia. While the Mongolian sea retreated from the west side through the periods, the route of migration was maintained toward the Mediterranean sea through the Himalayan geosyncline until the end of the Palaeozoic era. Some trilobites of Japan reveal relationship further toward the Australian and North American sides.
  • 田林 明
    1989 年 98 巻 1 号 p. 49-72
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
    Southern Ontario is a peninsula shaped region bounded by Lake Huron, Lake Erie, Lake Ontario and the Ottawa River. Since southern Ontario has the most favorable combination of environmental and marketing advantages, it enjoys various types of highly productive agriculture. Since the end of World War II the majority of farms in southern Ontario have become more specialized operations.
    The objective of this paper is to investigate the types of farms in southern Ontario and their principal characteristics mainly based on the observation of sample farms. Further, through the analysis of statistics and the pertinent literature, an attempt is made to explain some important features of the recent changes in the agricultural regions of southern Ontario.
    Beef cattle, dairy, hog, grain corn and tobacco farms were chosen to be examined as sample farms. Production of livestock occupies a central place in the agriculture of southern Ontario and much of the crop production is for livestock feed. On livestock farms self-sufficiency of feed is a fundamental principle. Crop rotation is widely practiced and large amounts of manure along with commercial fertilizer are used to help retain soil fertility. In terms of the farm operation, the majority are run only by family members with a few instances of employment of seasonal labour. Size of farms is relatively small in Canadian terms (40 to 120 hectares) but gross sales concentrated in the 40 to 90 thousand dollar a year range are slightly above the national average.
    Judging from these features, southern Ontario agriculture seems to be common to the traditional mixed farming systems of western Europe. However, farms in southern Ontario have been highly mechanized and commercialized. A large number of farms specialize in a single agricultural product.
    One of the most important changes in southern Ontario agriculture is the spread of grain corn and soybeans at the expense of hay, mixed grains and oats. This means that higher yielding/higher value crops are replacing lower yielding more traditional ones. Dairy and poultry farms are doing well economically, while beef and hog operations are not.
    Another change in southern Ontario is that industrialized agriculture has developed during the last thirty years. According to Troughton, “Agriculture is transformed from an activity generally carried out at a small-scale and moderate to low level of capital intensity, to one in which the major portion of production comes from a reduced number of large scale, highly capitalized units.”
    In addition, part-time farmers constitute increasing proportion of all farmers. Earnings from off-farm work are now very important for many farmers. There are also many “hobby farmers”. Their interests are mainly in rural living with little effort to maximize income from the farm operation.
    Lastly a process of regional specialization and diversifiation has advanced since World War II : the development of special crop regions, expansion of the corn belt and horticultural regions, and a growing contrast between the Canadian Shield and southern flat land areas.
  • 小泉 武栄
    1989 年 98 巻 1 号 p. 73-81
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 高橋 伸夫
    1989 年 98 巻 1 号 p. 82-83
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小泉 武栄
    1989 年 98 巻 1 号 p. Plate1-Plate2
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 久保 和也
    1989 年 98 巻 1 号 p. Plate3-Plate4
    発行日: 1989/02/25
    公開日: 2009/11/12
    ジャーナル フリー
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