Environmental effects of Deccan volcanism across the Cretaceous-Tertiary transition in Meghalaya, India

B. Gertsch, Gerta Keller, T. Adatte, R. Garg, V. Prasad, Z. Berner, D. Fleitmann

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

The Um Sohryngkew section of Meghalaya, NE India, located 800-1000km from the Deccan volcanic province, is one of the most complete Cretaceous-Tertiary boundary (KTB) transitions worldwide with all defining and supporting criteria present: mass extinction of planktic foraminifera, first appearance of Danian species, δ13C shift, Ir anomaly (12ppb) and KTB red layer. The geochemical signature of the KTB layer indicates not only an extraterrestrial signal (Ni and all Platinum Group Elements (PGEs)) of a second impact that postdates Chicxulub, but also a significant component resulting from condensed sedimentation (P), redox fluctuations (As, Co, Fe, Pb, Zn, and to a lesser extent Ni and Cu) and volcanism. From the late Maastrichtian C29r into the early Danian, a humid climate prevailed (kaolinite: 40-60%, detrital minerals: 50-80%). During the latest Maastrichtian, periodic acid rains (carbonate dissolution; CIA index: 70-80) associated with pulsed Deccan eruptions and strong continental weathering resulted in mesotrophic waters. The resulting super-stressed environmental conditions led to the demise of nearly all planktic foraminiferal species and blooms (>95%) of the disaster opportunist Guembelitria cretacea. These data reveal that detrimental marine conditions prevailed surrounding the Deccan volcanic province during the main phase of eruptions in C29r below the KTB. Ultimately these environmental conditions led to regionally early extinctions followed by global extinctions at the KTB.

Original languageEnglish (US)
Pages (from-to)272-285
Number of pages14
JournalEarth and Planetary Science Letters
Volume310
Issue number3-4
DOIs
StatePublished - Oct 15 2011

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Keywords

  • Deccan volcanism
  • Iridium
  • KT boundary
  • Mass extinction
  • Meghalaya

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