[meteorite-list] Carancas crater

[Michael Farmer]

Thanks for clarifying that Ted.
Michael Farmer



--- Ted Bunch <tbear1 at cableone.net> wrote:

> 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, "mmorgan at mhmeteorites.com"
> <mmorgan at mhmeteorites.com>
> 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 <meteoriteguy at yahoo.com>
> > 
> > Date: Thu, 28 Feb 2008 09:40:39
> > To:Adam Hupe <raremeteorites at yahoo.com>,Adam
> > <meteorite-list at meteoritecentral.com>
> > 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 <raremeteorites at yahoo.com> 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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