Carbon isotopic excursions and detailed ammonoid and conodont biostratigraphies around Smithian-Spathian boundary in the Bac Thuy Formation, Vietnam

Toshifumi Komatsu, Reishi Takashima, Yasunari Shigeta, Takumi Maekawa, Huyen Dang Tran, Tien Dinh Cong, Susumu Sakata, Hung Doan Dinh, Osamu Takahashi

研究成果: Article査読

22 被引用数 (Scopus)

抄録

The Smithian-Spathian boundary is indicated by the first occurrence of the ammonoid Tirolites cf. cassianus in the Olenekian Bac Thuy Formation, northeastern Vietnam. The boundary is intercalated within organic-rich dark gray mudstone that accumulated under anoxic to dysoxic conditions in the An Chau and Nanpanjiang Basins on the South China Block. In Lang Son area, three conodont zones, Novispathodus ex gr. waageni, Novispathodus ex gr. pingdingshanensis, and Icriospathodus collinsoni, are recognized in the formation. The Smithian-Spathian boundary is intercalated within N. ex gr. pingdingshanensis conodont Zone. The positive excursion inδ13C with values increasing from around -2.3‰ to +5.7‰ was recorded in the uppermost Smithian Xenoceltites variocostatus ammonoid beds and N. ex gr. pingdingshanensis conodont Zone. The δ13C values decrease across the Smithian-Spathian boundary. These δ13C isotopic patterns are correlated with well-known positive excursions around the Smithian-Spathian boundary globally.

本文言語English
ページ(範囲)65-74
ページ数10
ジャーナルPalaeogeography, Palaeoclimatology, Palaeoecology
454
DOI
出版ステータスPublished - 2016 7月 15

ASJC Scopus subject areas

  • 海洋学
  • 生態、進化、行動および分類学
  • 地表過程
  • 古生物学

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