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Australia: The Land Where Time Began |
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Deccan Volcanism State Shift at Cretaceous-Palaeogene Boundary Possibly
Impact Induced
Renne et al. suggest that at
the close of the Cretaceous leading candidates for the cause of the mass
extinction event are impact of a bolide and flood volcanism. It is
indicated by high precision 40Ar/39Ar data that
there may be genetic relationship between these 2 mechanisms, with the
result that neither can be considered in isolation. The magmatic system
of the existing Deccan Traps underwent a state shift approximately
coincident with the impact at Chicxulub and the mass extinction event at
the close of the Cretaceous, and following this event ~70 % of the total
volume of the Traps was extruded in more massive, more episodic
eruptions. Within ~50,000 years of the impact the new regime was
initiated, which is consistent with the transient effects of seismic
energy that is induced by an impact. Recovery of marine ecosystems is
suggested by Renne et al. to
have probably been suppressed until after the waning of the accelerated
volcanism.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |