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NWA 6593
(Northwest Africa)

L3 W4

31.3g
full slice

Meteoritical Bulletin Entry: http://www.lpi.usra.edu/meteor/index.php?code=53729


 

 
 
 
Below some backscatter electron images (brighter colours correspond to heavier elements) obtained with a SEM.
These images, together with their descriptions, were kindly provided by Jérôme Gattacceca (CEREGE; France) who classified this meteorite.
 
 
Image 1, 2, 3:
Type 1 (Fe-poor silicates, dark) and type 2 chondrules (Fe-rich silicates, bright). Note the zoning in olivine in type 2 chondrules, evidencing non equilibrium for olivines: iron starts to enter the olivine from the border. This process is basically finished by metamorphic type 3.5.
 

Image 1
 

Image 2
 

Image 3
 
 
 
Image 4 and 5 (zoom of 4):
Detail of type 2 chondrule, showing olivine zoning and glassy mesostasis. The dendrites in the mesostatis are Ca-rich pyroxene I think (not 100% sure). They correspond to a quenched texture. The same thing is visible in Semarkona for instance!
 


Image 4
 

Image 5
 
 
 
Image 6 and 7 (zoom of 6):
Again type 1/type 2 dichotomy.
 

Image 6
 

Image 7
 
 
 
Images 8, 9, 10: Progressive zoom on a very interesting feature: 
Dusty olivine (small metals blebs in the olivine) that is a sign of high "primitivity".
 

Image 8
 

Image 9
 

Image 10
 
 
 
Image 11:
Just a bunch of chondrules.
 

Image 11
 

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