[meteorite-list] Largest 'Fall' Meteorite

From: Matt Morgan <mail_at_meteoritecentral.com>
Date: Mon, 26 Oct 2009 22:48:23 +0000
Message-ID: <1200125080-1256597390-cardhu_decombobulator_blackberry.rim.net-2024921254-_at_bda677.bisx.prod.on.blackberry>

According to the AGI Glossary of Geology (4th ed)...
"An approximately circular or polygonal depression in the surface of a planetary object, having a diameter that may range from a few cm to hundreds of km and a depth that is small relative to its diameter."

This definition seems pretty loose to me. Perhaps it should have a raised rim (although if deeply weathered it may no longer exist) and be the result of a hypervelocity impact (not a bomb explosion). What about impact breccias?
Matt
----------------------
Matt Morgan
Mile High Meteorites
http://www.mhmeteorites.com
P.O. Box 151293
Lakewood, CO 80215 USA

-----Original Message-----
From: Jason Utas <meteoritekid at gmail.com>
Date: Mon, 26 Oct 2009 15:41:35
To: Meteorite-list<meteorite-list at meteoritecentral.com>
Subject: Re: [meteorite-list] Largest 'Fall' Meteorite

Right - the report I cited noted a mass about half that weight (1-1.5
tons) and vertical walls; I could be wrong, but I thought that the
determinant had to do with upended strata. If anyone here has the
criteria for what determines a crater versus an impact pit, I'd be
much obliged - if there is indeed a clear-cut definition.
Regards,
Jason

On Mon, Oct 26, 2009 at 3:25 PM, Matt Morgan <mail at mhmeteorites.com> wrote:
> I did some research on Sterlitamak, Russia for a presentation I gave to the Colorado Scientific Society in late 2008 on Non-Terminal Meteorite Impacts: The Case for Studying Small Cratering Events. ?Here is a summary of what I dug up on Sterlitamak:
> -Formed a crater 30 ft wide by 18 ft deep
> -Rays of ejecta extended 100 ft from crater
> -Blocks of soil and bedrock lined crater walls, 20 in dia. thrown 300 ft.
> -Impact breccias at crater floor to depth of 26 ft.
> -Impact velocity 2-3 km/sec
> -Impactor approx .9 m in dia and weighed 2-3 tons
> -Equiv to 1.5-2 tons TNT
>
> Sounds like a crater to me. I do believe it had an overturned flap of debris at the rim as well.
>
> Matt
> ----------------------
> Matt Morgan
> Mile High Meteorites
> http://www.mhmeteorites.com
> P.O. Box 151293
> Lakewood, CO 80215 USA
>
> -----Original Message-----
> From: Jason Utas <meteoritekid at gmail.com>
> Date: Mon, 26 Oct 2009 15:12:22
> To: Ted Bunch<tbear1 at cableone.net>; Meteorite-list<meteorite-list at meteoritecentral.com>
> Subject: Re: [meteorite-list] Largest 'Fall' Meteorite
>
> Right, but I don't believe that Campo del Cielo is noted as a
> witnessed fall. ?If we're going to start listing every crater
> associated with meteorite fragments, we're going to get a much longer
> list.
> The only accepted witnessed falls that have led to the formation of
> legitimate craters are Carancas and Sikhote Alin. ?Another list member
> suggested Sterlitamak; I still believe that, according to the
> description of the impact features found:
>
> http://adsabs.harvard.edu/abs/1992Metic..27R.276P
>
> - That this is an impact pit, not a crater. ?Note the description of
> sheer walls, etc.
> Regards,
> Jason
>
> On Mon, Oct 26, 2009 at 2:51 PM, Ted Bunch <tbear1 at cableone.net> wrote:
>> ?Rubin de Celis crater of the Campo del Cielo strewn field is a real crater
>> - 0.04 km dia with a raised rim. - see Passc Website.
>>
>> Ted Bunch
>>
>>
>> On 10/26/09 1:48 PM, "Jason Utas" <meteoritekid at gmail.com> wrote:
>>
>>> Yo,
>>> Sikhote-Alin, the largest crater at 26m in diameter.
>>> Only two meteorites are ever known to have created real craters upon
>>> falling; Carancas and Sikhote-Alin.
>>> Carancas' crater measures in at 13m.
>>> I suppose falls like Gao could have been larger in mass than Caracas,
>>> but I don't know if we even have a good estimate of the mass of
>>> Carancas, so perhaps someone more knowledgeable about the event could
>>> comment; the reports I could find online conflicted drastically.
>>> Regards,
>>> Jason
>>>
>>> On Mon, Oct 26, 2009 at 1:32 PM, Greg Stanley <stanleygregr at hotmail.com>
>>> wrote:
>>>>
>>>> All:
>>>> What is the Largest "Fall" known, and what was the size of the crater made?
>>>>
>>>> Greg S.
>>>>
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>>
>>
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Received on Mon 26 Oct 2009 06:48:23 PM PDT