[meteorite-list] Mammoth Stew

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Sun, 16 Dec 2007 19:38:24 -0800 (PST)
Message-ID: <600546.56205.qm_at_web36915.mail.mud.yahoo.com>

Hi Jason, all -

Firstly, it's not "my" crater, nor "my" impactites. I
first saw this on National Geographic TV, and had not
even read Firestone's Mammoth Trumpet piece until
Sterling pointed it out to us. This was Kenneth's
team's work.

Secondly, I made no estimate of crater size - though
if I were going to do so, I'd probably scale from
Firestone's C14 calibration chart. If I remember that
C14 chart right, the diameter should be smaller than
Canyon Diablo - so let's see, what is that, less than
a kilometer?

Thirdly, I don't think that the far north has been
explored as well as the lower part of North America.
Given the funding levels for this kind of work, I
think your assertion that a crater does not exist may
be a little premature. Its difficult to work up there.

Fourthly, others here have already mentioned glaciers
and glacial action. Don't you think they might have
affected any crater, or that there may have been an
ice impact?

Fifthly, about the best sceptical comment made here at
the meteorite list was the one about sparks from
welding. But then that hypothesis was shot down by the
observed bone healing, and the sample from Siberia,
so...

E.P. Grondine
Man and Impact in the Americas

>"If
> you look at impact crater distribution maps, you'll
> see that more have been found in the areas where
> geologists live."

Yes, and this impact of which you speak supposedly
occurred in the North America, one of the areas
(namely the US) with the largest number of geologists
in-residence in the world.

With regards to the rest of your statement, the
trouble with saying this that we simply haven't found
it yet is that technology and knowledge at the time,
back when the Yucatan crater was found, with regards
to impact craters and mechanisms was extremely
limited.
Nowadays, we know much more about them, and, were
there such a crater on the continent with such a young
age, I have *no* doubt that it would have already been
found. It's one thing to compare two similar craters,
but that's not what you're doing. You just compared a
(probably) 10-20 mile diameter crater with an age
younger than that of CD to a crater that, regardless
of its size, is sixty-five million years old, and has
been eroded to nothing visible.

Bad comparison. A thirty-thousand year old crater of
such a size would be painfully obvious, regardless of
where it was. You can try to deny this fact as much
as you like, but that makes it no lesser a fact.
You're talking about a crater 3/4 the age of CD, with
a
diameter ten to twenty times as large.

Ejecta fields would span the country, and probably
other continents as well. Have a look at the
australasian tektite field. It was formed
by a crater that might be no more than 10km across, or
so I hear, and we find these tektites strewn more than
halfway across the world, and many are turned up
(microtektites in any case) in core samples from
the bottom of the ocean, by chance. It's a 700,000
year old impact.

And yet we find no trace of your ~30,000 year old
impactites anywhere - not on the ground, under water,
or anywhere else. I'm inclined to believe that your
crater shares the same fate.

It's not hiding...if it did exist, we would have found
it...we haven't found it...it doesn't exist.

Jason



      ____________________________________________________________________________________
Looking for last minute shopping deals?
Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping
Received on Sun 16 Dec 2007 10:38:24 PM PST