[meteorite-list] Mammoth Stew

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Sun, 16 Dec 2007 22:46:20 -0800
Message-ID: <93aaac890712162246s107b0387h6cd28d870cd1a6ed_at_mail.gmail.com>

E.P., Sterling, 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.

Well, seeing as you're the only one advocating such a thing's
existence (everyone else says 'maybe,' if that), for our purposes, it
is essentially yours.

> 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?

Were we or were we not talking about something that wiped out 90% of
human life on the continent? I think an impactor in the ~1km
crater-making range just wouldn't be able to cope.

> 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.

Hmmm, yes and no. Fewer people live up there, but it has been gone
over much more thoroughly by geologists in search of diamonds, oil,
and natural gas; look at the number of craters up there if you don't
believe me.

> 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?

On a crater that must be this big?
No.

> 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...

Well they're not spheroids, so...eh.

Jason

> 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
>
>
>
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Received on Mon 17 Dec 2007 01:46:20 AM PST