Re: The K-T boundary in Nanxiong

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "John Bois" <jbois@umd5.umd.edu>

> So circular!  Anything that happened is predicted by bolide, therefore
> everything that happened was caused by the bolide.

Almost. Anything that happened is either predicted by the fact that there
was an impact, or it is compatible with it, therefore everything that
happened may well have been caused by the bolide until someone gets a better
idea. Still scientific and not circular.

> Is this a broad range--such that a strike is likely to fall
> into that range?

Likely... impacts of that magnitude are expected only once every 100 Ma. But
they obviously exist.

> Or, is it a very narrow range such that dinos were
> incredibly unlucky?

Doesn't look like it. Twice a global catastrophe is still a global
catastrophe. So far, no two mass extinctions look exactly the same, so the
size, place etc. of the impact can well have effects on who survives and who
doesn't, but the range for a big mass extinction can't be very small.
        Doesn't matter -- calculations of the exact teratonnage have been
done long ago. We can compare that to what we might perhaps be able to
calculate from the magnitude of the extinction. So far I haven't read
anything saying it was far too big or small.

> [...] as it stands, I perceive such surgery to be
> very unlikely in every valley, forest, island, cave,or
> antipodean refuge.

I really wouldn't call global wildfires and a Strangelove ocean surgery...
it's more like desinfection. :-) Antipodes... New Zealand burnt down just
like Japan and North America. So much for forests. Caves... well, something
did survive :-)

Someone else put up the question about how long plants can go without light.
Seeds can sometimes survive millennia in the ground.