Changes in depth-transect redox conditions spanning the end-Permian mass extinction and their impact on the marine extinction: Evidence from biomarkers and sulfur isotopes

Kunio Kaiho, Masahiro Oba, Yoshihiko Fukuda, Kosuke Ito, Shun Ariyoshi, Paul Gorjan, Yuqing Riu, Satoshi Takahashi, Zhong Qiang Chen, Jinnan Tong, Satoshi Yamakita

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Changes in redox conditions during the Changhsingian to Griesbachian spanning the end-Permian mass extinction were recently reported based on analyses of organic molecules. We provide more precise organic-molecular data, that detail redox conditions spanning the end-Permian mass extinction at different palaeowater depths in the neritic Palaeotethys (estimated water depths: 10, 40, 100, and 200m; Bulla, Huangzhishan, Meishan, and Chaohu sections, respectively) during this period. Here we propose that a change from occasional euxinia to anoxia in the shallow Palaeotethys occurred at the time of the mass extinction intercalated with oxic pulses. The second extinction at 0.7myr after the main extinction was also caused by anoxia. New and published sulfur-isotope ratios ( 34S/ 32S) measured in carbonate-associated sulfate from the neritic Palaeotethys and in sulfide from pelagic central Panthalassa sediments show high values during the Changhsingian, consistent with the development of euxinia. The mass extinction coincided with a global fall in δ 34S values, as well as a shift in δ 13C values, indicating a global oxidation of H 2S. This organic and isotopic geochemistry implies that accumulation of hydrogen sulfide in intermediate and deep waters followed by oxidation of hydrogen sulfide led to dissolved oxygen consumption, surface-water anoxia, and acidification, resulting in the end-Permian mass extinction in the seas.

Original languageEnglish
Pages (from-to)20-32
Number of pages13
JournalGlobal and Planetary Change
Volume94-95
DOIs
Publication statusPublished - 2012 Aug

Keywords

  • Anoxia
  • Biomarker
  • Dissolved oxygen
  • Euxinia
  • Mass extinction
  • Permian-Triassic
  • Sulfur isotope

ASJC Scopus subject areas

  • Global and Planetary Change
  • Oceanography

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