@article{oai:soar-ir.repo.nii.ac.jp:00020463,
 author = {保柳, 康一},
 issue = {7},
 journal = {地質学雑誌},
 month = {Jul},
 note = {The Middle Miocene Kotambetsu Formation is widely distributed in the Haboro area, northern part of central Hokkaido. The Kotambetsu Formation is dominated by coarse-grained sediments which were transported from the east. The sediments are classified into the following eleven lithofacies on the basis of the grain size and sedimentary structure ; graded conglomerate, non-graded conglomerate, pebbly sandstone, graded sandstone, non-graded massive sandstone, alternated graded sandstone and mudstone, alternated ripple cross-laminated sandstone and mudstone, mudstone, slump and pebbly mudstone facies. From their occurrence, they are grouped into four lithofacies assemblages. Furthemore, these lithofacies assemblage are grouped into two sedimentary facies associations (Association Ⅰ and Association Ⅱ), reflecting different sedimentary environments. The Association Ⅰ is made up of two lithofacies assemblages ; Assemblage A (mainly composed of graded conglomerate) and Assemblage B (mainly composed of alternated graded sandstone and mudstone). The former Assemblage indicates channel-fill deposits and the latter inter-channel deposits The Association Ⅰ sediments are regarded as turbidites deposited at the base of steep slope.<br/>Two lithofacies assemblages (C and D) with non-graded structure make the Association Ⅱ. The Association Ⅱ always overlies Association Ⅰ. Both associations, however, show laterally interfingering relationship. A change from the Association Ⅰ to the Association Ⅱ always took place earlier in the northeastern part nearer the source of sediments, whereas later in the southwestern part. The Association Ⅱ seems to have been deposited in proximal part and under shallower condition than the Association Ⅰ. The change of sedimentary environment took place after the trough had been filled with turbidites (Association Ⅰ). The two lithofacies assemblages of the Association Ⅱ are regarded as channel-fill and inter-channel deposits of the post-trough-fill stage respectively.<br/>The sedimentary process of the Kotambetsu Formation, proceeded from northeast to southwest in the following three stages : 1) the trough was infilled with turbidites (Association Ⅰ) in the northeastern area, 2) the depositional area of turbidites prograded southwestward and sedimentary facies was changed into the Association Ⅱ in the filling area, 3) the basin was infilled completely and deposition of the Association Ⅱ continued in the south western area.<br/>The sedimentary basin of the Kotambetsu Formation was situated on the westward slope formed by rapid uplifting of the adjacent eastern source area during the Miocene. The sedimentary process of the Kotambetsu Formation, is considered to have been controlled by juxtaposed erosional and depositional areas, and by migration of uplifting to the subsided basin., Article, 地質学雑誌.95(7):509-525(1989)},
 pages = {509--525},
 title = {埋積と前進に伴うタービダイトの岩層変化 : 中央北海道・中央中新統古丹別層},
 volume = {95},
 year = {1989}
}