著者

長浜 春夫 斎藤 洋彦 岡 重文

出版者

Japan Society of Engineering Geology

雑誌

応用地質 (ISSN:02867737)

巻号頁・発行日

vol.28, no.1, pp.25-34, 1987-03-25 (Released:2010-02-23)

参考文献数

15

被引用文献数

1 1

著者

長浜 春夫 斎藤 洋彦 岡 重文

出版者

一般社団法人日本応用地質学会

雑誌

応用地質 (ISSN:02867737)

巻号頁・発行日

vol.28, no.1, pp.25-34, 1987-03-25

被引用文献数

1

著者

斎藤 洋彦

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.67, no.5, pp.158-165, 1972-05-05 (Released:2008-08-07)

参考文献数

12

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The Kabasawa placer deposit is categorized as one of the Pliocene ilmenite placer deposit and its sedimentary and conservative environment is controlled by warping movement of the Okubushi line. the purpose of this paper lies in the research of such elements which influenced the deposition of the Kabasawa placer deposit characteristics relating to type of movement, behavior and development stage of the Okubushi line made during the Pliocene era. The Okubushi line consists of combinations of cross structure of NW and NE branches meeting at tangent angles to each other which reflects the tectonics in the basement of this area. Of these, the NW brach plays a main role in the tectonic movement. The NW branch of Okubushi line controlled the deposition in Pliocene Sendai Group as well as Pliocene sedimentary basin after making warping movement and bringing about an upheaval on its southwestern side and tilting subsidence on its northeastern side. In other words, the NW branch brought about a differential movement of upheaval and subsidence through the depositional stage of Kameoka and Tatsunokuchi formation and the central part of the past upheaval changed into a depressional tilting subsidence at the depositional stage of Kitayama formation. Finally, the NW branch terminated its geologic movement with the eruption of tuff (acidic volcanic deposits) at the depositional stage of Hirosegawa tuff. The Kabasawa sandstone and conglomerate member intercalating Kabasawa ilmenite placer deposit, is a deltaic deposit which was piled up upon the region of depressional tilting subsidence during the depositional stage of Kitayama formation. It forms a circle of 2km diameter and has an extraordinary thick stratum. It is generally believed that the movement in the NW branch of Okubushi line is the result of a tectonic movement, referred to as “Green Tuff Crustal Movement”, in full activity during the Miocene era and succeeded to the Pliocene era in the northeastern part of Japan.