環太平洋第三紀炭田およびその石炭化作用について

抄録

I. There are a number of Tertiary coal fields in the islands and coastal ranges of American continents, surrounding the Pacific Ocean. They may be grouped as the Circum-Pacific Tertiary coal fields, because their genesis is closely related to the same mountain-building movement which was active since the late Mesozoic age, and reached its acme during the late Neogene time.
II. The characteristic features of these coal fields are as follows :
1. The extension of the field is limited (usually less than 100 kilometers in length).
2. The depositional basin is paralic in nature, and lateral change of sediments as well as coal seams is remarkable.
3. They are usually subject to strong crustal movement.
4. Some fields are affected heavily by igneous intrusions.
5. The coalification has advanced in most fields in spite of their young age, and the degree of coalification changes within a short distance even in one and the same field.
III. The author, after discussing the influential factors concerning coalification, concluded that the pressure produced during crustal movement cannot be neglected, against the current views of the coal chemists who maintain that the pressure plays only a subordinate role. He suggested that high pressuremedium temperature tests will contribute to the understanding of coalification of the Circum-Pacific Tertiary coal fields.