Re: The dinosaurs did not die in fire, from the latest Geology

[Graydon <oak@uniserve.com>]

On Thu, Dec 04, 2003 at 11:39:03AM -0800, Phil Bigelow scripsit:
> Phrased another way:  The researchers' premise is that soot and
> iridium-laden dust are both delicate atmospheric precipitates, and if
> both events occurred, and if one component is *preserved* at a
> particular K-T boundary layer site, then the other component *must* be
> preserved there as well.  Any anomaly from the expected result can be
> used as evidence for falsification of the world-wide wildfire
> hypothesis.  This is a reasonable premise.

I think that's a rash assumption, actually.  Iridium-rich metallic dust
is going to have higher sectional density and possibly (I have no idea)
a different particle shape and charge-holding characteristics than
carbon dust, so I'd expect there to be rather different precipitation
behaviours.

It'd be a bear to get good experimental data on how fast the iridium
dust falls, too, but perhaps the other parts are cheap enough to throw
from airplanes? :)

-- 
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                 |   -- The Seafarer, ll. 117-118.