[meteorite-list] AD - Dunitic diogenite NWA 2968 and JAH 626 melted eucrite full slices

[Fabien Kuntz]

Hello, 



reading this artricle about DAWN, Vesta and HED : 

http://meetingorganizer.copernicus.org/EPSC2012/EPSC2012-82-1.pdf

I decided to put on my website two full slices of the eucrite Jiddat al Harasis 626 and my last specimens of the dunitic diogenite NWA 2968.




NWA 2968 is massive olivine-rich rock of very large grain size (17 to >25 mm), found as many rectangular/blocky specimens in 2004. In most of cases these specimens are multicentimetric single olivine crystals, and because linear compression and shear fractures subparallel to one of the extinction directions in olivine, the exterior looks very shiny, seen with the correct angle. Like primitive achondrites brachinites and martian meteorites chassinites, NWA 2968 is composed >95% of olivine, and is a dunitic diogenite according the new largely adopted diogenite classification system - Beck and McSween (2010), Wittke et al. (2011). For the exemple, you can see pictures of thin sections made on the specimens for sale : 

http://www.wwmeteorites.com/Ventes/NWA%202968%20classic.jpg
http://www.wwmeteorites.com/Ventes/NWA%202968%20disrupted%20with%20veins.jpg

All the three last specimens I have can be found here. Last sale, low price : 

http://www.wwmeteorites.com/Ventes/NWA2968.html




Jiddat al Harasis 626 is a polymict breccia composed of both basaltic eucrite and cumulate eucrite. Clasts in this largely melted zircon-bearing eucrite represents very different part of the asteroid Vesta surface, from deep eucritic cumulate to surface rocks. Acoording the study, the spectral reflectance mesurment of JaH 626 (to be compared to DAWN spacecrat data) as for  NWA 2968  plot well  outside  the  traditional  HED  field (Beck,  P.  et  al.  (2011) Icarus,  216, 560-571)  : 

http://origin-ars.els-cdn.com/content/image/1-s2.0-S0019103513000444-gr4.jpg

The  spectral  properties  of  these  "anomalous"  HEDs are  consistent  with  expectations,  and  indicate  that much  more  spectral  (and  compositional)  diversity may  be  found  on  the  surface  of  Vesta than  expected from "traditional" HEDs. So I just produced two compltete slices on the main mass, now on the JAH 626 pages with the smaller ones : 

http://www.wwmeteorites.com/Ventes/JAH626.html



Regards, Fabien


Fabien Kuntz
Météorites (ventes, expertise, conférences)
Animation scientifique et technique
WWMETEORITES (Siret : 511 850 612 00017)
www.wwmeteorites.com