[meteorite-list] ARCTIC IRONS - the hunt is on

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Tue, 25 Dec 2007 21:31:49 -0800 (PST)
Message-ID: <182573.31839.qm_at_web36903.mail.mud.yahoo.com>

Hi Sterling, all -

Hopefully now that Jason and Darryl have stopped their
harassment, we can begin to define the problem space
for the arctic iron hunt. I don't intend to let either
of them waste another minute of my time, and would
recommend to others here that they follow a similar
course.

Going back to Firestone's piece in the Mammoth Trumpet
in March, 2001, which Sterling provided us the link to
(Sterling, would you please do so again), we see
spikes in Carbon 14 production in the accepted radio
calibration curve INTCAL98.

Running through time, the first of these spikes at (by
eyeball) 46,000 BCE may be associated with the
Barringer Crater Impact.

The next spike at 40,000 BCE is unassociated with any
impact crater that I know of. There may be one, it's
simply that I don't know it or can't recall it; if
anyone knows of a candidate impact do tell. I seem to
vaguely remember that there were South American
impactites found at Rio Cuarto which did not come from
the 2,360 BCE event, but came from a much earlier one.
Does anyone here know of any impact or impactite which
might match?

The next spike at 31,000 BCE appears to be from the
Mammoth Pepperer Impact. Judging from the calibration
chart, this crater should have been just a tad bigger
than Barringer Crater, if the iron hit land. Of
course, that land is tundra, so the crater edges most
likely will not remain sharp today.

>From the BBC report, we see that the most intense
peppering occurred in Alaska, where the mammoth tusks
were found (no longer a Calgary shop, as per earlier
reports). There was some doubt among Firestone's team
as to whether the mammoths died at the time of impact,
and some of them were clearly hoping the tusks were
peppered later at 10,900 BCE. Remarkably, they did not
seem to understand the difference in impactites coming
from an iron impact and a comet impact.

A healed ox skull from Siberia shows that the iron
peppering was less intense there - the ox survived.

Looking at the ice sheet maps from 31,000 BCE, while
this was the Laurentide ice maximum, strangely enough
Alaska was ice free in its north - they know this from
pollen samples. The mammoth were eating something to
live, after all. This was what was left of an earlier
ice free "corridor", which would reopen again later.

Thus the possibility of a large undiscovered crater
somewhere in that ice free area of Alaska remains, no
matter what kinds of tantrums some people throw.

The tusks show jagged unhealed edges - which is to say
immediate death. A problem here is that ballistic
re-entry means condensed spherules will arrive back to
Earth with the same force with which the iron plasma
left, so an ice impact still can not be ruled out.

We have the spherule distribution from the Barringer
Impact to go on for comparison. Can someone here
provide the information which Nininger gathered? That
distribution could be compared with the peppering
density preserved in the tusks, which might give some
kind of range.

If we knew exactly where the tusks and the ox skull
were found it would help. Alaska and Siberia are big
places.

The next C14 spike ca. 13,000 BCE is probably related
to the following one at 10,900 BCE, the cometary
impact now proved by Kenneth's team's recovery of the
North American impactite layer at that date, some of
the peoples' memories of which I have repeated here
from my book.

good hunting, and Merry Christmas,
E.P. Grondine
Man and Impact in the Americas












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Received on Wed 26 Dec 2007 12:31:49 AM PST