神居古潭帯の沙流川(さるがわ)超塩基性岩体について(<特集>日本列島のオフィオライト-地団研第31回総会テーマ別討論会-)
スポンサーリンク
概要
- 論文の詳細を見る
The Kamuikotan Belt, a tectonic belt of the centralaxial zone of Hokkaido, is characterized by the presence of numerous serpentinite masses. A serpentinite mass in the southern part of the belt is called the Saru-gawa Ultrabasic Massif. Based on the geologic structure, the massif is divided into the Western Unit and the Eastern Unit. The mutual relation of these two units indicates that the block including the Eastern Unit was thrusted to the block including the Western Unit. Petrography of the ultrabasic rocks in the two units is asfollows; original rock of the ultrabasic rock in the Western Unit is represented by the layerd-textured Iwanai-dake peridotite surrounded by serpentinite. The Iwanai-dake peridotite body consists of dunite, harzburgite, and olivine orthopyroxenite, all of which carry a small amount of clinopyroxenes. The original rock of serpentinite in the Eastern Unit is inferred to be composed mostly of dunite and harzburgite, which contain more clinoproxene than the Western Unit. In addition, lherzolite and olivine websterite are also noticeable in the Eastern Unit. Dike-formed microdiorite, quartz albitite, and clinopyroxenite are observed in the ultrabasic rocks of the both units, although these dike rocks, except microdiorite, are predominant in the Eastern Unit. Other massifs composed mainly of serpentinite are known in the northern part of the Kamuikotan Belt (e.g. the Pinneshiri massif, the Horokanai massif). It may be interpreted that these serpentinite massifs represent complexes composed of several different ultrabasic rock units judging from the mode of their distribution.
- 地学団体研究会の論文
- 1978-11-25