- 著者
- 田切 美智雄 森本 麻希 望月 涼子 横須賀 歩 DUNKLEY Daniel J. 足立 達朗
- 出版者
- Tokyo Geographical Society
- 雑誌
- 地學雜誌 (ISSN:0022135X)
- 巻号頁・発行日
- vol.119, no.2, pp.245-256, 2010-04-25
- 参考文献数
- 29
- 被引用文献数
- 8 20
Hitachi metamorphic rocks located in the southern part of the Abukuma Mountains, Northeast Japan, distinctively contain meta-volcanic rocks and meta/sheared granitoids. The igneous ages of meta-granite and meta-porphyry from the Hitachi metamorphic rocks were determined by the SHRIMP zircon method. In this paper, we describe occurrence, petrography, and petrochemical characteristics of these studied rocks. Meta-porphyry, with an igneous age of 506 Ma, intrudes into the meta-volcanic rocks of the Akazawa Formation of the Hitachi metamorphic rocks and has a micrographic texture and a spherulitic texture of an igneous origin. Previous studies have already reported an igneous age of 491 Ma for meta/sheared granitoids using the SHRIMP zircon method. Cambrian meta/sheared granitoid samples occur widely as a granitic body in the northeastern part of the Hitachi metamorphic rocks. (A) Meta-granite of the same age (498 Ma) as the sample used for the above dating is found as boulders in meta-conglomerates. The meta-conglomerate, which is found in the Daioin Formation of the Hitachi metamorphic rocks, lies unconformably on a Cambrian meta-granite body. Both meta-volcanic rocks and meta/sheared granitoids have chemical characteristics commonly associated with island arc volcanism. As such, the Akazawa Formation is likely to have originated in the Cambrian era, although we have no SHRIMP age for meta-volcanic rocks of the Akazawa Formation.
- 著者
- 鈴木 和博 Suzuki Kazuhiro 中村 俊夫 Nakamura Toshio 加藤 丈典 Kato Takenori Takenori 池田 晃子 Ikeda Akiko 後藤 晶子 Goto Akiko 小田 寛貴 Oda Hirotaka 南 雅代 Minami Masayo 上久保 寛 Kamikubo Hiroshi 梶塚 泉 Kajizuka Izumi 足立 香織 Adachi Kaori 壺井 基裕 Tsuboi Motohiro 常磐 哲也 Tokiwa Tetsuya 太田 友子 Oota Tomoko 西田 真砂美 Nishida Masami 江坂 直子 Esaka Naoko 田中 敦子 Tanaka Atsuko 森 忍 Mori Shinobu ダンクリー ダニエル Dunkley Daniel J. クシャク モニカ Kusiak Monika A. 鈴木 里子 Suzuki Satoko 丹生 越子 Niu Etsuko 中崎 峰子 Nakazaki Mineko 仙田 量子 Senda Ryoko 金川 和世 Kanagawa Kazuyo 熊沢 裕代 Kumazawa Hiroyo
- 出版者
- 名古屋大学年代測定資料研究センター
- 雑誌
- 名古屋大学加速器質量分析計業績報告書
- 巻号頁・発行日
- vol.19, pp.26-38, 2008-03
Umi is located along the Kamimura River within the Kamiyahagi area of southeastern Ena City, Gifu Prefecture. The name 'Umi' means sea or large lake; however, there are no lakes in the mountainous Kamiyahagi area. The Tokai Gou (torrential rain) flood of September 11-12, 2000 destroyed embankments along the river, and exposed sedimentary layers that are typical of a lacustrine depositional setting. This confirms the existence of a paleo-lake from which the name Umi originated. The ^<14>C ages, ranging from 280±37 to 345±25 BP, appear to be contemporaneous with Tensho Earthquake that occurred in central Japan on January 18, 1586.