Shawn,
For now there are three scenarios which are spelt out between the two
abstracts. While talking with one of the scientists earlier, he pointed out
that it is very hard to make a comment similar to yours in regards to the
CRE age of NWA 5400 and that he would explain it further to me in a way I
can state it to the List. It is not as cut and dry as you put it. I will
have to wait for his call as I am not a scientist and refer to experts when
needed.
Hope this helps with your patience.
Best regards,
Greg
====================
Greg Hupe
The Hupe Collection
NaturesVault (eBay)
[email protected]
www.LunarRock.com
IMCA 3163
====================
Click here for my current eBay auctions:
http://search.ebay.com/_W0QQsassZnaturesvault
----- Original Message -----
From: "Shawn Alan" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>
Sent: Wednesday, September 29, 2010 1:39 AM
Subject: [meteorite-list] [Announced June 8, 2010] NWA 5400: Earth-Related
Meteorite
Hello
Greg H and Listers,
That's funny you brought that up because 10 mins ago I found that in the
2010 paper that had the CRE which I over looked, and this is what it
says....
Noble Gases: Noble gases in two samples of NWA 5400 were analyzed by total
melting and stepwise heating. The cosmic ray exposure age based on
spal-logenic 3He and 21Ne is ~29 Ma, which is within the range of exposure
ages of brachinites (3-57 Ma; [9]). The meteorite shows a large 129Xe excess
(~3×10-10 cm3/g) derived from 129I decay (T1/2 = 16 Ma), indica-tive of its
formation very early in Solar System history.
Now if I am reading this correctly, this means that the CRE age puts the NWA
5400 at ~29 Ma. This would mean that this fragment couldn't have came from
the 4 billion year old Thea impact that has been speculated? If that was the
case, that this fragment came from ejecta from Earth, the CRE would have to
4 billion years old, but that's not the case.
Further more in bother papers other ideas have been presented on where NWA
5400 which as follows.
Alternatively, NWA 5400 may represent the ultramafic portion of an
asteroidal parent body that witnessed similar processing to brachinites, but
that evolved more slowly (larger?) and originated from a composi-tionally
distinct reservoir, yet one with similarities to the planetary feeding zones
of the Earth-Moon system.
And
Thus we are left with the possibility that NWA 5400 could be an ancient
terrene meteorite, or else a sample from a different, differentiated
Earth-like body.
Now with the CRE proven and matched with other brachinites at less then 30
millions years this might contradict that NWA 5400 was ejected in space from
the Thea impact, which in turn proves that NWA 5400 didn't directly come
from Earth from that catastrophic event.
Lastly its seems that brachinites have been the topic of interest and in the
2009 paper it stated that they formed 4.564 Ga. However, in the 2010 paper
its stated that NWA 5400 is younger then brachinite. Now if NWA was formed
before then, wouldn't that also contradict when Earth was formed if it came
from Earth because if NWA 5400 is related to Earth, then the formation age
should match up?
Shawn Alan
IMCA 1633
eBaystore
http://shop.ebay.com/photophlow/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340
[meteorite-list] [Announced June 8, 2010] NWA 5400: Earth-Related
MeteoriteGreg Hupe gmhupe at htn.net
Wed Sep 29 01:08:58 EDT 2010
Previous message: [meteorite-list] AD - New Stuff at KD Meteorites!
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Shawn and Others:
Since some people did not read or forgot what I wrote in my very first
announcement of NWA 5400 on June 8, 2010, here it is to review. You will
notice in the second abstract dated 2010 that the Cosmic Ray Exposure date
HAS been determined. Now how scientists compile that data with other
information is for them to study, ponder and write new abstracts.
June 8, 2010 [Meteorite Central List]
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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