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Re: Location Narrowed For Permian/Triassic Impact



> "Coincide exactly"?
> I wonder how the researchers managed to achieve that level of
> geochronological precision at for an event that occured 250 million years
> ago, considering that radiometrically-dated Pleistocene artifacts
> ("yesterday", geologically-speaking) typically have at least a +/- 500
> year error bar.

Indeed, last time I looked there were about 100,000 years in between. (Which
is quite probably smaller than just about any error margin.)

> > The dinosaur extinction 65 million
> > years ago coincided with similarly
> > extensive eruptions in India.

Here, however, it's quite easy to trust the data that say that the biggest
episode of Deccan volcanism _ended_ 100,000 years before the K-T boundary.
The same method should be applied to P-Tr marine sediments, some of which
allow a resolution of 8,000 years (by cyclostratigraphy -- preserved
Milankovic cycles).

> 3) A test of the "Volcanism Causes Mass Extinctions" hypothesis:  The
> huge Miocene Columbia River plateau basalt flows (CRB) are not correlated
> to any recognizable mass extinction (nor are the flows correlated to any
> recognizable local extinctions).

Most basalt traps aren't correlated to any recognizable mass extinction. :-)