Sedimentological study of the Paleogene basin of Kushiro in Hokkaido,Japan.
Sedimentological study of the Paleogene basin of Kushiro in Hokkaido,Japan.
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日本北海道钏路古近纪盆地沉积学研究.
DOI：
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发表时间：
1962
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通讯作者：
Masaru Matsui
中科院分区：
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作者：
Masaru Matsui
钏路煤田位于日本最北部的主岛北海道东部的南侧。到目前为止，关于该盆地古近系地层学的研究已有许多成果，包括作者本人的研究。在本文件中，这些研究的结果将简要概述在第一。在研究过程中，最显著的事实是：1）在煤盆地的初始阶段，相对于地层等厚线、岩石和化石的非均相界线，总的趋势似乎是西-东方向;集会这被称为早期的Urahoro阶段。2)第二阶段也可识别出多种生物相和沉积相。然而，它们的排列总趋势是NNE到SSW。盆地的最深处位于东部。这被称为后Urahbro阶段。3)下一阶段盆地整体上比前一阶段加深。此外，从生物相和沉积相的角度来看，盆地似乎更均匀。尽管如此，沉积物在厚度上显示出局部差异。等厚线总的趋势与前阶段一样，向近NNE tg SSW方向延伸。盆地的最深处似乎一直在从东向西移动。这是早来音别舞台。4)在晚温别期，盆地最厚的部分向西移动，几乎位于原沉积盆地的边缘。火山产物沿着前一阶段盆地最深处的界线发育。5)盆地最厚部分由东向西迁移的特征不仅在古近系沉积盆地中可见，而且从白垩纪一直延续到上新世或近代。这种情况意味着存在的“古根室岛”的一些影响，这是！位于这个沉积盆地的东南边缘最后简要讨论了构造与沉积相及地层厚度的关系。沉积过程中的构造运动，如层内褶皱、无平面断层和砂岩岩墙的出现，在沉积中最突然的扰动发生的地区和层位都有证据。此外，盆地的沉积特征也影响了油气田的地质构造，即断裂和褶皱的方向、位置与盆地的上述沉积特征相吻合。
The Kushiro coal basin is situated on the south side of the eastern part of Hokkaido, the northernmost main island of Japan. Until the present, there have been many contributions regarding the stratigraphy of the Paleogene formations in this basin, including the author's own studies. In the present paper, the results of these studies will be briefly outlined at first. Then the development of the Paleogene basin will be described in detail, The most remarkable facts observed in the course of this study are as follows : 1) In the initial stage of the coal basin, the general trends seem to have been ih' a West-East directiofi, in respe6t to the directioh of isopach lines of formations, the boundary line of heterofacies in rocks and fossi!-assemblages. This is named the Early Urahoro stage. 2) Various kinds of bio-facies and sedimentary facies can be recognized in 2nd stage too. Their general trends in arrangement, however, tend to be NNE to SSW. The deepest part of the basin is situated in the eastern part. This is denominated the Later Urahbro stage. 3) In the next stage the basin becomes deepef than it was in the former stage as a whole. Further, the basin seems to have been more uniform throughout, from the view point of bioand sedimentary facies. In spite of this, ,the sediments show local differences in thickness. The general trend of isopach lines extends nearly NNE tg SSW, like th6 'pteceding stage. The deepest part of the basin seems to' hav6 been 'shifting far from east to west. This is the Eariy Onbetsu stage. 4) In the Later Onbetsu stage, the thickest part of the basin has been much moved towards the west, lying nearly at the edge of the former sedimentary basin. ' Volcanic products were developed along the lines of the deepest part of the basin of the preceeding stage. 5) The characteristic of the migration of the thickest part of the basin towards the west from the east is not only observable in the Paleogene sedimentary basin but also it continues from the Cretaceous to Pliocene or Recent. This condition implies the existence of and some effect of the "Paleo-Nemuro Iand" which was !ocated on the south-eastern edge of this sedimentary basin. Lastly the relation between tectonic and sedimentary facies as well as thickness of formation will be discussed briefly. Structural movements during the process of sedimentation such as occurrence of intraformational foldings, planeless faults and sandstone dykes, are evidenced in areas and horizons where the most sudden disturbances in sedimentation took place. Furthermore, the geological structure of this field has been infiuenced by the features of sedimentation, namely the direction and position of faults and axes of foldings are in coincidence with the sedimentational features of this basin as above stated.