NWA 5426 R4

NWA 5426 is a Rumuruti type chondrite. Most R chondrites show brecciation, though Rumuruti itself does not. They have a somewhat high ratio of matrix to chondrules and very little metallic nickel-iron. Chondrules tend not to be the fully melted types (barred, radial, cryptocrystalline and glassy) but, as you’ll see below, there are exceptions. Here are close-ups of a slice of another R chondrite and then a short tour of NWA 5426 in thin section.

A polished slice of a brecciated R chondrite. The piece is 4 cm wide.

 

A close-up of the same slice. Lower right - a light colored lithology. Top right – dark matrix. Top left – a fine grained, chondrule poor lithology. Scattered - several smaller dark clasts.

 

Photo taken in both incident light and transmitted cross polarized light. The upper right portion appears more altered that the rest.

 

Large and small mineral fragments and a variety of chondrules.

 

Chondrule with a thin rim.

 

Mineral fragment with a poikilitic texture. Orange chondrule has a coarse barred form.

 

Compound barred chondrule surrounded by a dark jacket.

 

A variety of mineral fragments and chondrules.

 

Closer.

 

Closer.

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About the Author

John Kashuba
John is a natural history enthusiast living in Oregon.
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