[meteorite-list] Large Angrite Slices - NWA 4931 - AD

From: Greg Hupe <gmhupe_at_meteoritecentral.com>
Date: Tue, 22 Sep 2009 14:07:00 -0400
Message-ID: <77BE369E4A3D4242BCA53CE9613876AE_at_Gregor>

Dear List Members,

About a week ago I announced NWA 4931, the angrite that was flown to MIT in
2007 where a core sample was taken for magnetism analysis. I was able to get
large slices cut from the largest mass after the coring was completed. It
was cut and polished by one of the best professionals out there! I would
like to offer what I have available at discounted prices. Here is the list
with photo links (measurements are in millimeters). The description of NWA
4931 is below the list in this email.

In addition to announcing NWA 4931, I also have some very nice achondrite
meteorite auctions ending on eBay tomorrow, Wednesday, September 23rd. Click
here for my current eBay auctions:
http://search.ebay.com/_W0QQsassZnaturesvault

***Available specimens of angrite NWA 4931***

685g Fragment (no coring was done on this piece).
110mm x 90mm x 40mm
http://www.lunarrock.com/nwa4931/dsc00001.jpg

302g end cut
100 x 70 x 32
http://www.lunarrock.com/nwa4931/dsc00003.jpg

58.5g slice (has part of core hole along back side).
108 x 70 x 3
http://www.lunarrock.com/nwa4931/dsc00006.jpg

56.8g slice
105 x 69 x 3
http://www.lunarrock.com/nwa4931/dsc00007.jpg

32.2g part slice
67 x 49 x 3.5
http://www.lunarrock.com/nwa4931/dsc00008.jpg

29.8g part slice
68 x 53 x 3
http://www.lunarrock.com/nwa4931/dsc00009.jpg

23.3g part slice
64 x 45 x 3
http://www.lunarrock.com/nwa4931/dsc00010.jpg

22.7g part slice
62 x 43 x 3
http://www.lunarrock.com/nwa4931/dsc00011.jpg

22.4g part slice (has part of core hole along back edge).
62 x 40 x 3
http://www.lunarrock.com/nwa4931/dsc00012.jpg

17.2g part slice (has part of core hole along back edge).
58 x 40 x 3
http://www.lunarrock.com/nwa4931/dsc00014.jpg

16.3g part slice
59 x 38 x 3
http://www.lunarrock.com/nwa4931/dsc00015.jpg

14.8g part slice
68 x 23 x 3.5
http://www.lunarrock.com/nwa4931/dsc00016.jpg

8.9g part slice (has part of core hole along back edge).
49 x 27 x 3
http://www.lunarrock.com/nwa4931/dsc00019.jpg

I have priced these at $75.00 per gram for the polished slices and can offer
further discounts on the large fragment and end cut. If you are interested
in any of these specimens, please email me Off-List. Thank you for
considering these beautiful angrite specimens!

Here is my description of NWA 4931 with photo links of the coring and
overall meteorite:

Start>>
NWA 4931, the Main Mass to the now famous angrite, NWA 2999. NWA 4931 has a
Total Known Weight (TKW) of 2140 grams in two interlocking fragments, which
form a complete stone. Surprisingly, the two parts were recovered by nomads
months apart in the Sahara Desert in 2007. The first 1314-gram half was
flown to Massachusetts Institute of Technology in Boston where scientists
extracted a core sample in order to conduct magnetism tests, which they
hoped would provide vital evidence indicating the size of the Angrite Parent
Body (APB).

Image of 1314-gram stone representing 60% of entire mass (cube: 1-inch
square):
http://www.lunarrock.com/nwa4931/nwa4931complete1.jpg

Link to image of core sampling at MIT laboratory:
http://www.lunarrock.com/nwa4931/nwa4931core.jpg

Image of 66-gram complete slice displaying abundant xenocrysts:
http://www.lunarrock.com/nwa4931/nwa4931slice.jpg

An international consortium of scientists, led by Dr. Benjamin Weiss of MIT,
took a new approach to the problem by testing samples from several angrites
with an extremely sensitive magnetometer. They discovered the material
showed evidence of ancient magnetic fields similar to those of rocks formed
on Earth within the planet's magnetic field. In other words, as the team
reported in the October 31, 2008 issue of Science, these 4.56
billion-year-old meteorites once were part of bodies that were either big
enough or hot enough to produce central, molten, metallic cores.

Link to LPSC abstract on magnetic field on Angrite Parent Body:
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2143.pdf

"The meteorites, therefore, are essentially magnetic recording tapes," says
Weiss. The magnetic fields that they recorded were probably generated by
molten metal swirling around inside the planet's core like a giant, rotating
dynamo, as happens on Earth. Angrites are among the oldest known pristine
basaltic meteorites ever found and have provided new clues about the
conditions that existed at the beginning of the solar system, solving a
longstanding mystery and overturning some accepted ideas about the way
planets form. They still contain magnetic records about the earliest stages
of planet formation and differentiation.

ScienceNOW Daily News: October 30, 2008:
http://sciencenow.sciencemag.org/cgi/content/full/2008/1030/2

Science October 31, 2008:
http://www.sciencemag.org/cgi/content/abstract/322/5902/713

Link to abstract reporting ages of angrites NWA 2999, NWA 4801 and NWA 4590
"Tamassint":
http://www.lpi.usra.edu/meetings/metchron2007/pdf/4061.pdf

BSE image of corona textures in NWA 4931.
http://www.lunarrock.com/nwa4931/nwa4931bse.jpg
End<<

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
Received on Tue 22 Sep 2009 02:07:00 PM PDT