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ID 117648
Title Alternative
The second discovery of a Late Cretaceous ammonite from the Shimanto Belt in Mugi, Tokushima Prefecture, eastern Shikoku, Japan
四国東部の四万十帯からの後期白亜紀アンモナイト
Author
Tsujino, Yasuyuki Tokushima Prefectural Museum
Wada, Hidemi Kaifu Nature Network
Hirayama, Masanori Kaifu Nature Network
Keywords
Cretaceous ammonite
Gaudryceras cf. tombetsense
Mugi Melange
Shimanto Belt
Tokushima
Content Type
Journal Article
Description
A Late Cretaceous ammonite was discovered from the lower section of the Mugi Melange of the Shimanto Belt in the Kusunoura area, Mugi, Tokushima Prefecture, Japan. The ammonite is identified with Gaudryceras cf. tombetsense reported from the K2 unit (Maastrichian) of the Krasnoyarka Formation, Makarov area, southern Sakhalin, Russia. The lower section of the Mugi Melange is assigned to the early Paleogene, based on a recently obtained U-Pb zircon age. It is reasonable to assume that the ammonite from the Kusunoura area was trapped as an exotic block within the lower section of the Mugi Melange.
Description Alternative
徳島県牟岐町楠之浦地域に分布する四万十帯牟岐メランジュ下部セクションより,後期白亜紀アンモナイトを発見した.このアンモナイトは,ロシア・サハリン南部マカロフ地域のクラスノヤルカ層の岩相ユニットK2(マストリヒチアン階)から報告されたGaudryceras cf. tombetsenseに最も似ている.最近のジルコンU-Pb年代に関する研究に従うと,牟岐メランジュ下部セクションの年代は古第三紀初頭を示す.現時点では,楠之浦地域から発見された後期白亜紀アンモナイトは,古第三紀堆積物である牟岐メランジュ下部セクションの中に外来岩塊として含まれたと考えるのが妥当である.
Journal Title
The Journal of the Geological Society of Japan
ISSN
00167630
13499963
NCID
AN00141768
Publisher
日本地質学会
Volume
116
Issue
12
Start Page
680
End Page
685
Published Date
2010-12
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
jpn
TextVersion
Publisher
departments
Science and Technology