State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact

Abstract

Bolide impact and flood volcanism compete as leading candidates for the cause of terminal-Cretaceous mass extinctions. High-precision (40)Ar/(39)Ar data indicate that these two mechanisms may be genetically related, and neither can be considered in isolation. The existing Deccan Traps magmatic system underwent a state shift approximately coincident with the Chicxulub impact and the terminal-Cretaceous mass extinctions, after which ~70% of the Traps' total volume was extruded in more massive and more episodic eruptions. Initiation of this new regime occurred within ~50,000 years of the impact, which is consistent with transient effects of impact-induced seismic energy. Postextinction recovery of marine ecosystems was probably suppressed until after the accelerated volcanism waned.

The End of Midcontinent Rift Magmatism and the Paleogeography of Laurentia

“…However, large igneous provinces associated with the arrival of upwelling mantle plumes often result in short (~1 m.y.) pulses of intense and voluminous volcanism (e.g., Blackburn et al, 2013;Burgess et al, 2015;Renne et al, 2015). In contrast, magmatism in the Midcontinent Rift was prolonged over tens of millions of years.…”

X Conferencias y Seminarios del Doctorado en Geología

“…Schoene et al (2015) proponen que el 80% de las coladas basálticas se emitieron en los 250 ka anteriores al límite K/Pg (Figura 1) propiciando un evento de extinción previo a dicho límite. No obstante, las propuestas de Richards et al (2015) y Renne et al (2015) sugieren que sería el impacto de Chicxulub el que desencadenaría hasta el 70% de las coladas basálticas en aproximadamente los 500 ka siguientes al límite K/Pg (Figura 1). Schoene et al (2015) (izquierda) y de Richards et al y Renne et al (2015) (derecha)…”

Untitled

“…The rapid extrusion of lava, in less than 1 million years [2] would be expected for an antipodal eruption. This is a stronger cause-and-effect than the proposal that the seismic waves from an impact increased the outflow of the Deccan Traps eruption [109,110]. …”