@article{oai:niigata-u.repo.nii.ac.jp:00003226,
 author = {成田, 耕一郎 and 山路, 敦 and 田上, 高広 and 栗田, 裕司 and 小布施, 明子 and 松岡, 數充},
 issue = {4},
 journal = {地質学雑誌, 地質学雑誌},
 month = {Apr},
 note = {Cenozoic clastic sediments in the Kuma area, Shikoku, southwest Japan, previously designated as the Kuma Group, are here redefined as the Hiwada-toge Formation and the overlying Kuma Group sensu strict, considering a significant time-gap between them. The Hiwada－toge Formation is Early Eocene in age on the basis of dinoflagellate cysts, while the lower part of the Kuma Group s.s. (Sagayama Formation) was dated as late Early Miocene by fission-track dating. Organic microfossil assemblages show that the Hiwada-toge Formation contains marine strata and the lower part of the Kuma Group s.s. (Sagayama Formation) is of non-marine origin. These results provide two geochronological constraints critical to the regional tectonic history. The age of the Hiwada-toge Formation indicates that the Sanbagawa metamorphic rocks came under subaerial erosion by Early Eocene in its provenance area. The relationship between the Median Tectonic Line (M.T.L.) and the northern extension of the Miocene Kuma Group s.s. and its contiguous strata shows that a compresional activity of the M.T.L. occurred during a relatively short period in late Early to Middle Miocene.},
 pages = {305--308},
 title = {四国の第三系久万層群の堆積年代とその意義},
 volume = {105},
 year = {1999}
}