[meteorite-list] AD - NWA 6963, 4 fresh slices of a martian close to Shergotty

From: Fabien Kuntz <wwmeteorites_at_meteoritecentral.com>
Date: Fri, 22 Jun 2012 21:10:39 +0100 (BST)
Message-ID: <1340395839.68474.YahooMailNeo_at_web29602.mail.ird.yahoo.com>

Hello list,


after a busy post-Ensisheim week, I have now found the time to prepare for the list slices of the NWA 6963 martian meteorite... This meteorite is realy hard to cut correctly, because easily broken in crumps/dust during process, but shows an amazing matrix when work done !

NWA 6963 shows a minimal weathering (2 of my slices display nice fresh crust), and high shock grade, based on complete transformation of plagioclase to maskelynite (for a total of about 35% !).


Its realy looks-like the Shergotty meteorite in structure, and by exemple, the pyroxen chemistry on NWA 6963 is realy close of the first of the shergottite :


http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1696.pdf


Mineral Compositions and Geochemistry: Electron microprobe analyses reveal two distinct pyroxene compositional trends present in NWA 6963: a pigeonite trend ranging from Fs29Wo11En59 to Fs58Wo16En26 with an average value of Fs39.7?7.7Wo13.0?2.3 (n=108), and an augite trend ranging from Fs21Wo34En45 to Fs39Wo31En30, with an average value of Fs28.1?6.2Wo31.6?1.9. Figure 2 shows that NWA 6963 pyroxene compositions are similar to the pyroxene compositional trends in the Shergotty martian meteorite. Fe/Mn (molar) of pyroxenes has been used successfully to categorize planetary basalts. NWA 6963 pigeonites have Fe/Mn=33?3 and augites with Fe/Mn=31?3 which are consistent with average SNC values.

Specimen 0.54g slice - 432$

http://www.wwmeteorites.com/NWA6963/NWA6963-0.54g-01.JPG
http://www.wwmeteorites.com/NWA6963/NWA6963-0.54g-02.JPG

Specimen 0.58g slice - 464$

http://www.wwmeteorites.com/NWA6963/NWA6963-0.58g-01.JPG
http://www.wwmeteorites.com/NWA6963/NWA6963-0.58g-02.JPG

Specimen 2.21g slice with two crusted edge? - 1660$

http://www.wwmeteorites.com/NWA6963/NWA6963-2.21g-01.JPG
http://www.wwmeteorites.com/NWA6963/NWA6963-2.21g-02.JPG

Specimen 2.32g slice with two crusted edge? - 1740$

http://www.wwmeteorites.com/NWA6963/NWA6963-2.32g-01.JPG
http://www.wwmeteorites.com/NWA6963/NWA6963-2.32g-01.JPG

Upon request, an 22.65g endcut shows orientation, with flowlines and lips of crust !

Fabien


Fabien Kuntz
M?t?orites (ventes, expertise, conf?rences)
Animation scientifique et technique
WWMETEORITES (Siret : 511 850 612 00017)
www.wwmeteorites.com?
Received on Fri 22 Jun 2012 04:10:39 PM PDT