2024-03-29T01:23:23Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/367322022-11-17T02:08:08Zhdl_2115_34911hdl_2115_34816hdl_2115_116The Takadomari Serpentinites in the Kamuikotan Ophiolite Belt, Hokkaido, JapanIgarashi, ToshihikoKatoh, TakayukiNiida, Kiyoaki450Within the Kamuikotan Ophiolite Belt, a large serpentinite mass more than 10×12 km is observed around Takadomari as a tectonic unit of dismembered ophiolite. The Takadomari serpentinites show an east-facing layered structure composed primarily of dunite, harzburgite, and olivine-orthopyroxenite layers. More than 120 dykes of microdiorite-microgabbro were found in the serpentinite mass and clearly show an intrusive relation. The serpentinization is characterized by a progressive crystallization of antigorite replacing lizardite and chrysotile serpentines crystallized retrogressively. The Takadomari mass is regarded as a dismembered ophiolite unit which is situated at the base of the Horokanai ophiolite complex. High pressure and low temperature type metamorphic rocks such as glaucophane schist are considered to be a tectonic unit lifted up by the Takadomari serpentinites.北海道大学Departmental Bulletin Paperapplication/pdfhttp://hdl.handle.net/2115/36732https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/36732/1/21_3_p305-319.pdf0018-3474北海道大学理学部紀要2133053191985-08engpublisher