Day #53 Deskcrop: Gabbronorite

What do you call an equigranular, phaneritic rock made of plagioclase, orthopyroxene, and clinopyroxene? Well, if they’re in roughly equal proportions like the rock below the technical term is gabbronorite. This deskcrop comes from along the Benbow Mine Road in the Stillwater Intrusion of Montana. It’s not the first, and it certainly won’t be the last deskcrop you’ll see from the Stillwater Intrusion.

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Gabbronorite

Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!

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