The Cretaceous-tertiary mass extinction, Chicxulub impact, and Deccan volcanism

Gerta Keller

Research output: Chapter in Book/Report/Conference proceedingChapter

33 Scopus citations


After three decades of nearly unchallenged wisdom that a large impact (Chicxulub) on Yucatan caused the end-Cretaceous mass extinction, this theory is facing its most serious challenge from the Chicxulub impact itself, as based on evidence in Texas and Mexico and from Deccan volcanism in India. Data generated from over 150 Cretaceous-Tertiary (KT) boundary sequences to date make it clear that the long-held belief in the Chicxulub impact as the sole or even major contributor to the KT mass extinction is not supported by evidence. The stratigraphic position of the Chicxulub impact ejecta spherules in NE Mexico and Texas and the impact breccia within the crater on Yucatan demonstrate that this impact predates the KTB by about 300,000 years. Planktic foraminiferal and stable isotope analyses across the primary impact ejecta layer reveal that not a single species went extinct as a result of this impact and no significant environmental changes could be determined. The catastrophic effects of this impact have been vastly overestimated. In contrast, recent advances in Deccan volcanic studies indicate three volcanic phases with the smallest at 67.5 Ma, the main phase at the end of the Maastrichtian (C29r), and the third phase in the early Danian C29r/C29n transition (Chenet et al. 2007). The main phase of eruptions occurred rapidly, was marked by the longest lava flows spanning 1500 km across India, and ended coincident with the KT boundary. The KT mass extinction may have been caused by these rapid and massive Deccan lava and gas eruptions that account for ~80% of the entire 3500 m thick Deccan lava pile.

Original languageEnglish (US)
Title of host publicationEarth and Life
Subtitle of host publicationGlobal Biodiversity, Extinction Intervals and Biogeographic Perturbations Through Time
PublisherSpringer Netherlands
Number of pages35
ISBN (Electronic)9789048134281
ISBN (Print)9789048134274
StatePublished - Jan 1 2012

All Science Journal Classification (ASJC) codes

  • Earth and Planetary Sciences(all)
  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)


  • Chicxulub impact
  • Cretaceous
  • Danian
  • Deccan volcanism
  • Foraminifers
  • Maastrichtian
  • Mass extinctions
  • Paleogene
  • Stable isotopes


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