石炭資源探査技術の動向 : 新しい石炭地質学 Introduction to Modern Coal Exploration Technology--Modern Coal Geology
Coal geology is induced from the general geologic phenomena investigated in coal exploration and researches relevant to coal. Therefore coal geology has been progressing in accordance with coal mining and utilization. Progress of coal geology in Japan was impeded its progress in 1960s due to declining domestic coal mining and influence of misunderstood cyclothem concept in most of researches. However, a few geologists tried to investigate the deeper areas, far beyond economical exploration, by means of depositional modeling of the already developed areas.<BR>Recent progress in coal geology in the world established basin analysis with depositional modeling and verified the origin of coal-bearing formations to deltaic environments, not to cyclothem, except some of the intermontane lacustrine coal basins. Research of Recent peat swamps and interpretation of geophysical exploration have significantly contributed to the progress.<BR>For coal exploration, especially the Tertiary coal-bearing formations, basin analysis by means of measuring the directions of paleocurrents is impossible due to scarcity of sandstone outcrop where the direction of paleocurrent can be measured. Instead of such a method, the lithofacies coding method is more practical both in logging with a specially designed work sheets and in analysis of the basin with depositional modeling.