Coolidge C4 – ung

The namesake of the Coolidge grouplet of meteorites was found in 1937 and has been classified H4, CV4 and C3.8-ung. Studies distinguish Coolidge from CK chondrites (which contain type 4 examples) and from CV chondrites. Some chondrules are large and layered from repeated accretion and heating in the solar nebula.

Skeletal crystals inside a chondrule. Coolidge C4 – ung.

 

A large, layered chondrule – the result of several episodes of accretion and heating. Chondrule diameter is 3.5 mm. Coolidge C4 – ung.

 

The round black spots are blebs of metal. Coolidge C4 – ung.

 

An aggregate of fine olivine grains 2 mm in diameter. Coolidge C4 – ung.

 

A chondrule with two intersecting sets of olivine bars. Are the sets crystallographic twins? Coolidge C4 – ung.

 

The same chondrule with the crossed polarizing filters rotated so that one set of bars is in extinction. Coolidge C4 – ung.

 

The other set of bars is in extinction while the other set is visible. Coolidge C4 – ung.

 

2.25mm long. Coolidge C4 – ung.

 

Most of the dark areas inside this feature are metal. Coolidge C4 – ung.

 

The same feature in incident light with the metal showing silver-gray. Coolidge C4 – ung.

 

A radial pyroxene chondrule with a slightly scalloped (and cratered?) edge. It is one half millimeter in diameter. Coolidge C4 – ung.

About the Author

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