Ted and List,
I'm happy to see you weigh in on this. Maybe this will stop the quibbling.
I sense an odor of sour grapes in this thread anyhow.
If one [or more] of our "team" managed to get there and survey the site,
survive angry protestations, bring back a quantity for us to share, why
quibble over terminology.
Subsequent investigations corroborate earlier assessments and now this
meteorite is being recognized for its historic import.
HYPERVELOCITY is the watch word anyway. That don't happen every day[at least
witnessed!]
Jerry Flaherty
----- Original Message -----
From: "Ted Bunch" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "Michael Farmer" <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>; "Adam Hupe"
<[EMAIL PROTECTED]>; "Adam" <[email protected]>
Sent: Thursday, February 28, 2008 2:07 PM
Subject: Re: [meteorite-list] Carancas crater
I am not sure why there is an argument about whether or not Carancas is an
impact crater. Of course it is! In scientific terminology, impact pit is
not
acceptable. Let's review the facts:
1) The Carancas crater was produced by a hypervelocity impactor that
excavated a deep hole and formed a raised rim of target materials
(unconsolidated clastic debris).
2) Produced ejecta rays out 350 m from the crater
3) The event had sufficient shock energy to cause classic shock features
in
target quartz.
4) There is no size limitation for use of the term "crater" as long as the
feature fits the accepted scientific constraints, e. g., formed by
hypervelocity impact. LDEF (Long Duration Exposure Facility) flew in space
for 5.5 years and studies of the facility skin showed thousands of craters
as small as a few microns. Similar tiny craters have been found all over
space shuttle vehicles. Apollo glassy spherules and rock samples show tiny
impact craters as do several meteorite surfaces. In all of these cases,
scientific reports used the term "crater".
Ted Bunch
(an innocent bystander with 40 + years of professional experience in
impact
cratering)
On 2/28/08 11:01 AM, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
wrote:
All:
See the site (http://unb.ca/passc/ImpactDatabase).
On the first page you will find the criteria for inclusion within this
database (which is the most comprehensive and well-researched list on the
planet). Sikhote-Alin is listed, Carancas is not (yet?). Also note Wabar
and
Haviland, both of which are termed "craters" and do fall within Adam's
range
of 5-20 m.
The term impact "pit" is not listed in the Glossary of Geology (Jackson,
1997,
4th ed.), and is thus likely a loosely-used definition. Impact crater is
listed in the Glossary and is defined as "a generally circular crater
formed
either by impact of a projectile on a planetary surface or by an
experimental
hypervelocity impact of a projectile into solid matter..."
I would hedge a bet that Carancas will be considered an impact crater.
Matt
----------------------
Matt Morgan
Mile High Meteorites
http://www.mhmeteorites.com
P.O. Box 151293
Lakewood, CO 80215 USA
-----Original Message-----
From: Michael Farmer <[EMAIL PROTECTED]>
Date: Thu, 28 Feb 2008 09:40:39
To:Adam Hupe <[EMAIL PROTECTED]>,Adam
<[email protected]>
Subject: Re: [meteorite-list] Carancas crater
I did not realize that the website you listed was the
definitive and final place which determines craters vs
pits. It seems that some of the top scientists in the
world think that it is a crater, perhaps you should
enlighten them.
Carancas is a crater, and I am not sure:), but I do
believe that the impact of a meteorite created it,
thus, I am still confused, but would that not tend to
suggest that it is meteoritic? Adam, I think
regardless of whether it is a common chondrite, the
simple fact that it exists forces science to
re-calculate its models for impact craters by
chondrites. So Carancas is extremely important. I
forsee papers written about Carancas for decades.
There will be no roof built, the crater is already
mostly destroyed (as I predicted that it would be,
thanks to those of us who went there, at least some
material was preserved).
Michael Farmer
--- Adam Hupe <[EMAIL PROTECTED]> wrote:
Hi Mike and List Members,
To me, Carancas produced an "impact pit" which is a
form of crater. I will concede the point that it is
also a crater by other definitions, just not
meteoritic. The Sikhote Alin event also produced
several impact pits that were described as such
further constraining the meteoritic definition of an
impact crater.
Here is a great reference site that clearly defines
crater sizes of 5-20 meters as "impact pits".
Carancas only produced a 13 meter mud hole squarely
defining it as a pit.
http://www.somerikko.net/old/geo/imp/listinfo.htm
Pretty soon, the Carancas impact pit it will be no
more than a depression in the ground with urine,
fecal
matter and trash in it. Not to forget, a $90,000.00
roof will be added on top of a rotted out and the
most
common type of ordinary chondrite in existence at
the
bottom.
All the best,
Adam
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