Petrological characteristics of Dark-colored silica veins in Tertiary rhyolite (the Iozen Formation) from the southern part of Ishikawa Prefecture, Japan

• Morishita Tomoaki

  Graduate School of Natural Science and Technology, Kanazawa University

• Arai Shoji

  Graduate School of Natural Science and Technology, Kanazawa University

• Wakimoto Rie

  Graduate School of Natural Science and Technology, Kanazawa University

• Mizuta Toshio

  Institute of Earth Sciences and Technology, Akita University

• Ishiyama Daizo

  Institute of Earth Sciences and Technology, Akita University

• Sato Hinako

  Institute of Earth Sciences and Technology, Akita University

• Umeka Masaru

  Graduate School of Natural Science and Technology, Kanazawa University

• Fujisawa Akiko

  Graduate School of Natural Science and Technology, Kanazawa University

• Moriichi Shingo

  Graduate School of Natural Science and Technology, Kanazawa University

• Ohzeko Mitsuhiro

  Graduate School of Natural Science and Technology, Kanazawa University

• Mori Takami

  Graduate School of Natural Science and Technology, Kanazawa University

• Yamazaki Mayu

  Graduate School of Natural Science and Technology, Kanazawa University

• Yamamoto Shinya

  Graduate School of Natural Science and Technology, Kanazawa University

Bibliographic Information

Other Title

• 石川県南部地域の第三紀流紋岩（医王山累層）中に産する暗色珪質脈の岩石学的特徴
• イシカワケン ナンブ チイキ ノ ダイ3キ リュウモンガン イオウゼン ルイソウ チュウ ニ サンスル アンショクケイシツ ミャク ノ ガンセキガクテキ トクチョウ

Abstract

Anastomosing networks of massive dark-colored veins (Dark-colored silica veins hereafter) ranging from a few millimeters to 8 cm in thickness occur in a fault zone of Tertiary rhyolites (the Iozen formation) from the southern Ishikawa Prefecture, Japan. Optical microscopic observations combined with SEM and XRD studies revealed that the Dark-colored silica veins mainly consist of very fine-grained quartz (10 μm in size) with minor amounts of feldspar and Fe-bearing unidentified phase. Angular to subangular lithic clasts derived from the host rhyolite are frequently embedded in fine-grained quartz matrix of the Dark-colored silica veins. The Dark-colored silica veins are apparently abundant in SiO₂ relative to the host rocks. Chondrite-normalized rare earth element (REE) pattern of a Dark-colored silica vein is similar to that of the host rhyolite for middle to heavy REE, whereas light REE (La and Ce) concentrations are higher in the Dark-colored silica vein than in the host rhyolite, resulting in high La/Yb ratio in the Dark-colored silica vein. The Dark-colored silica veins might be originated by extreme crushing of the host rhyolite in fault zones followed by the selective enrichment of SiO₂ (+LREE) coupled with diluting of other elements. The outcrop including the Dark-colored silica vein was finally suffered from low-temperature alternation (<100ºC), leading to form clay minerals, particularly along the fault zone.<br>

Journal

• The Journal of the Geological Society of Japan

  The Journal of the Geological Society of Japan 112 (4), 273-283, 2006

  The Geological Society of Japan

Keywords

• northern Hokkaido
• Koetoi Formation
• Yuchi Formation
• diatom fossil
• fission track age
• <i>Neodenticula koizumii</i> Zone

Details

• CRID: 1390282681214870528
• NII Article ID: 110004734735
• NII Book ID: AN00141768
• DOI: 10.5575/geosoc.112.273
• ISSN: 13499963
• ISSN: 00167630
• NDL BIB ID: 7941545
• Web Site: http://hdl.handle.net/2297/2539
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7941545
• Web Site: https://www.jstage.jst.go.jp/article/geosoc/112/4/112_4_273/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • IRDB
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed