[meteorite-list] NWA 5400: Earth-Related Meteorite

From: Alan Rubin <aerubin_at_meteoritecentral.com>
Date: Thu, 10 Jun 2010 08:40:38 -0700
Message-ID: <0D69189194524F158C1A3956FA818A59_at_igpp.ucla.edu>

I think that the speculation is getting way out of hand. It seems very
unlikely to me that the meteorite is a piece of Earth, proto-Earth or of the
Mars-size planet that is inferred to have smacked the Earth 4.5 billion
years ago to form the Moon. The meteorite has a basically chondritic bulk
composition and, prior to terrestrial weathering, had fresh metal. It is
therefore probably not from a differentiated body. The only chondrites we
know that have terrestrial-like O-isotope compositions are enstatite
chondrites and CI chondrites. CI chondrites are essentially all matrix and
are probably unrelated to NWA 5400. And, of course, enstatite chondrites
are far more reduced than NWA 5400. Nevertheless, at least one enstatite
chondrite has been oxidized after having been impact-heated and partly
melted in proximity to oxidized material. That would be Galim. I haven't
studied NWA 5400 (although I would like to), but I'm guessing that its
origin is more likely to be that of an enstatite chondrite that was altered
by aqueous fluids and impacts than as some early progenitor of Earth.


Alan Rubin
Institute of Geophysics and Planetary Physics
University of California
Los Angeles, CA 90095-1567
phone: 310-825-3202
e-mail: aerubin at ucla.edu
website: http://cosmochemists.igpp.ucla.edu/Rubin.html


----- Original Message -----
From: "Richard Kowalski" <damoclid at yahoo.com>
To: "Greg Hupe" <gmhupe at htn.net>; <meteorite-list at meteoritecentral.com>;
"Stuart McDaniel - Action Shooting Supply" <actionshooting at carolina.rr.com>
Sent: Wednesday, June 09, 2010 8:34 PM
Subject: Re: [meteorite-list] NWA 5400: Earth-Related Meteorite


>I don't want to speak for Greg, but yes, that is one possible origin.
> It could be from the proto-Earth, the Mars sized impactor that stuck the
> proto-Earth, (this is the impact that formed the moon) or the remnants of
> that event.
>
> No matter which, it is an awesomely exciting meteorite!
>
> --
> Richard Kowalski
> Full Moon Photography
> IMCA #1081
>
>
> --- On Wed, 6/9/10, Stuart McDaniel - Action Shooting Supply
> <actionshooting at carolina.rr.com> wrote:
>
>> From: Stuart McDaniel - Action Shooting Supply
>> <actionshooting at carolina.rr.com>
>> Subject: Re: [meteorite-list] NWA 5400: Earth-Related Meteorite
>> To: "Greg Hupe" <gmhupe at htn.net>, meteorite-list at meteoritecentral.com
>> Date: Wednesday, June 9, 2010, 5:30 PM
>> So this could be a piece of Earth
>> before Earth was Earth??
>>
>>
>> Stuart McDaniel
>> Lawndale, NC
>> Secr., CCAS
>> ----- Original Message ----- From: "Greg Hupe" <gmhupe at htn.net>
>> To: <meteorite-list at meteoritecentral.com>
>> Sent: Tuesday, June 08, 2010 7:31 PM
>> Subject: [meteorite-list] NWA 5400: Earth-Related
>> Meteorite
>>
>>
>> > Dear List Members,
>> >
>> > I would like to announce an important new meteorite
>> that has been under intense analysis over the last two years
>> by a select group of scientists from around the world...
>> >
>> > NWA 5400: Earth-Related Ungrouped Meteorite
>> >
>> >
>> > Northwest Africa 5400 may be a sample from a large
>> asteroid or dwarf planet, which accreted in the early solar
>> nebula in the vicinity of proto-Earth or Theia. NWA 5400 has
>> oxygen isotope ratios indistinguishable from those of rocks
>> from the Earth and the Moon, which plot on the TFL
>> (Terrestrial Fractionation Line). A precise formation age
>> has not yet been measured, but it cannot be older than 4.54
>> billion years, which likely makes NWA 5400 anomalously young
>> among primitive achondritic objects from the early Solar
>> System. It is generally accepted that the Earth-Moon system
>> was created when Theia collided with proto-Earth about 4.3
>> billion years ago. Is it possible that NWA 5400 is somehow
>> related to this phenomenal event?
>> >
>> >
>> >
>> > NWA 5400 adds valuable understanding of events that
>> took place in the early evolution period of the Solar
>> System. After two years of intense analysis, scientists at
>> prominent institutions from around the world continue to
>> diligently study this 'stand-alone' meteorite, which will
>> add to the already incredible information NWA 5400 has to
>> offer.
>> >
>> >
>> >
>> > Link to 2009 LPSC abstract on NWA 5400:
>> >
>> > http://www.lpi.usra.edu/meetings/lpsc2009/pdf/2332.pdf
>> >
>> >
>> >
>> > Link to 2010 LPSC abstract on NWA 5400:
>> >
>> > http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1492.pdf
>> >
>> >
>> >
>> > NWA 5400 has a Total Known Weight of 4.818 kg in a
>> single stone that was discovered in Northwest Africa in
>> 2008. The chocolate-brown mottled matrix takes an extremely
>> nice polish, which reveals the dazzling olivine crystals
>> exhibited in this scientifically important new meteorite!
>> >
>> >
>> >
>> > Cross-polarized light optical thin section image of
>> NWA 5400 (width of field = 1.2mm):
>> >
>> > http://www.lunarrock.com/NWA5400/nwa5400xpl.jpg
>> >
>> >
>> >
>> > Image of 58.9-gram complete slice with hologram-like
>> olivine crystals that dance across the polished surface when
>> tilted from side to side:
>> >
>> > http://www.lunarrock.com/NWA5400/nwa5400slice.jpg
>> >
>> >
>> > Best regards,
>> > Greg
>> >
>> > ====================
>> > Greg Hupe
>> > The Hupe Collection
>> > NaturesVault (eBay)
>> > gmhupe at htn.net
>> > www.LunarRock.com
>> > IMCA 3163
>> > ====================
>> > Click here for my current eBay auctions:
>> > http://search.ebay.com/_W0QQsassZnaturesvault
>> >
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>> >
>>
>>
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Received on Thu 10 Jun 2010 11:40:38 AM PDT