Chemostratigraphy Across the Cretaceous-Paleogene (K-Pg) Boundary: Testing the Impact and Volcanism Hypotheses

Alcides Nobrega Sial, Jiubin Chen, Luis Drude Lacerda, Robert Frei, John A. Higgins, Vinod Chandra Tewari, Claudio Gaucher, Valderez Pinto Ferreira, Simonetta Cirilli, Christoph Korte, José Antonio Barbosa, Natan Silva Pereira, Danielle Santiago Ramos

Research output: Chapter in Book/Report/Conference proceedingChapter

5 Scopus citations

Abstract

The mass extinction which marks the K-Pg has been linked to a catastrophic event. Cr and Os isotopes and 3 He/4He ratios of He encapsulated in fullerenes within Ir-rich K-Pg layer point to an extraterrestrial cause, while Hg/TOC spikes across the K-Pg boundary suggest Hg loading from the Deccan volcanism. Three Hg/TOC spikes are present in some classical K-Pg sections: (i) spike I within the CF2 planktic foraminiferal biozone, (ii) spike II at the K-Pg boundary layer, and (iii) spike III within the P1a planktic foraminiferal subzone. The spike II has, perhaps, resulted from Hg loading from the asteroid impact and volcanism. We suggest that higher ΣREE+Y values in the K-Pg layers are, perhaps, related to Deccan volcanism or to sea-level fluctuations, coeval to the K-Pg transition that enhanced continental influx. True negative Ce anomaly suggests predominance of oxidized surface waters during the K-Pg transition. In a δ202Hg versus Δ201Hg plot, samples from the spike II and from Bidart-France lie within the Hg volcanic emission box. Samples from spikes I and III from Bidart lie within the volcanic emission/chondrite box. Small positive Δ201Hg favors long-term atmospheric transport and supports Hg loading to the environment by Deccan phase 2 in three distinct episodes.

Original languageEnglish (US)
Title of host publicationGeophysical Monograph Series
PublisherJohn Wiley and Sons Inc.
Pages223-257
Number of pages35
DOIs
StatePublished - 2018

Publication series

NameGeophysical Monograph Series
Volume240
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

All Science Journal Classification (ASJC) codes

  • Geophysics

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