Short-term euxinia coinciding with rotaliporid extinctions during the Cenomanian-Turonian transition in the middle-neritic eastern North Atlantic inferred from organic compounds

Masahiro Oba, Kunio Kaiho, Takashi Okabe, Marcos A. Lamolda, James D. Wright

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Oceanic anoxic event 2 (OAE2), which occurred during the Cenomanian-Turonian (C-T) transition and lasted 1 m.y., is characterized by a positive global carbon isotopic excursion and stepwise extinctions in marine biota. To examine temporal variations in the dissolved oxygen content of the water column, shallow-marine C-T sediments from northern Spain were analyzed for concentrations of dibenzothiophenes, which are indicators of euxinic depositional environments, and 2,3,6-trimethylarylisoprenoids, which probably indicate photic-zone euxinia. The positive excursion in δ13C values of carbonates is accompanied by short-term (103- 104 yr) and long-term (105 yr) increases in dibenzothiophene and 2,3,6-trimethylarylisoprenoid concentrations, suggesting that the bottom water and photic zone of the eastern marginal sea of the North Atlantic Ocean were euxinic. Two of the short-term increases in organic compound concentrations took place just after the last occurrence of the planktonic foraminifers Rotalipora greenhornensis and R. cushmani. These transient maxima indicate that the extinction of both planktonic foraminifers was due to short-term OAEs lasting 103-104 yr.

Original languageEnglish
Pages (from-to)519-522
Number of pages4
JournalGeology
Volume39
Issue number6
DOIs
Publication statusPublished - 2011 Jun 1

ASJC Scopus subject areas

  • Geology

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