Metal-troilite Intergrowths

Sometimes melt rock in meteorites contains blebs of metal-troilite (FeS) intergrowths. Here are examples from two rocks. NWA 869 is the well known L3-6 regolith breccia. It took a pounding on the surface of its parent body and contains a variety of clasts including melt rock. All 95 grams of NWA 6579 is melt rock. The composition of its olivine and its metal tell that it is an L ordinary chondrite.

Typical metal-troilite intergrowth texture. NWA 869 L3-6 regolith breccia. Field of view is 2 mm wide.

 

Metal and troilite side by side, that is, not intergrown. NWA 869 L3-6 regolith breccia. Field of view is 4 mm wide.

 

A triangular metal-troilite intergrowth sitting to the left of a lone bronze colored grain of troilite. NWA 869 L3-6 regolith breccia. Field of view is 2 mm wide.

 

A pair of droplets. NWA 869 L3-6 regolith breccia. Field of view is 3 mm wide.

 

Another pair. NWA 869 L3-6 regolith breccia. Field of view is 3 mm wide.

 

Irregular metal-troilite assemblage. NWA 869 L3-6 regolith breccia. Field of view is 2 mm wide.

 

Metal-troilite intergrowth. NWA 6579 L-melt rock. Field of view is 3 mm wide.

 

An atypical intergrowth. NWA 6579 L-melt rock. Field of view is 3 mm wide.

 

An atypical intergrowth. NWA 6579 L-melt rock. Field of view is 3 mm wide.

 

Typical metal-troilite intergrowth. NWA 6579 L-melt rock. Field of view is 3 mm wide.

 

Three blebs. NWA 6579 L-melt rock. Field of view is 4 mm wide.

About the Author

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