Saturday, October 03, 2015

Antipodal Volcanism and the K-T Extinction Event

In considering the extinction of the dinosaurs and related reptilian fauna, I found it interesting that the volcanic eruptions identified as the Deccan Traps marking the Indian peninsula are close to the antipode of the Chicxulub impact—the impact that is accused of initiating a cataclysmic cascade culminating in this extinction event, dubbed the K-T Extinction. Since the Deccan Traps and the Chicxulub crater are dated to approximately the same time period, I often wondered if the Deccan volcanic eruptions were the result of antipodal volcanism, that is, the result of the shockwaves of the Chicxulub impact traveling though the earth's mantle to the other side of the world.

Recently, this hunch has found more scientific support, namely that the Chicxulub impact at the very least greatly accelerated the Deccan eruptions already in progress, or at the most may have initiated them.

  • Double trouble: asteroid, volcanoes implicated in dinosaur doom
    [The researchers] said eruptions in a region called the Deccan Traps were already underway at a lower intensity but dramatically accelerated after the asteroid strike as if the powerful impact triggered it.
  • Giant asteroid may have triggered deadly volcano eruptions
  • Science: State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact
    “the Chicxulub impact initiated a substantial acceleration of Deccan volcanism”
  • Geol. Soc. Am. Bull.: Triggering of the largest Deccan eruptions by the Chicxulub impact
    “It is therefore reasonable to hypothesize that the Chicxulub impact might have triggered the enormous Poladpur, Ambenali, and Mahabaleshwar (Wai Subgroup) lava flows, which together may account for >70% of the Deccan Traps main-stage eruptions. This hypothesis is consistent with independent stratigraphic, geochronologic, geochemical, and tectonic constraints, which combine to indicate that at approximately Chicxulub/Cretaceous-Paleogene time, a huge pulse of mantle plume–derived magma passed through the crust with little interaction and erupted to form the most extensive and voluminous lava flows known on Earth.”
  • Asteroid, Volcanoes Double Whammy Doomed Dinosaurs
    The impact of the asteroid changed the underground plumbing in the volcanoes, making some magma chambers larger so they spouted more lava when they erupted. ... "The scenario we are suggesting -- that the impact triggered the volcanism -- does in fact reconcile what had previously appeared to be an unimaginable coincidence."
  • Consider also the relationship between the antipodes on a Cretaceous globe here: Princeton University - Impact study: Princeton model shows fallout of a giant meteorite strike
This antipodal relationship demonstrates that the continents have been moving and supplies us with a snapshot of where North America and India were at the K-T Extinction Event.

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