Stop 3 Martinsville-Henry County Virtual Field Trip

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Stop 3

The third stop was beside the lube area of the Wal*Mart. There are some black rocks cropping out on the grassy patch beside the road leading to Lowe's.

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Across the street are the same metamorphic rocks you just saw behind Tokyo Express.

This black rock at the feet of those students is the … wait for it… Rich Acres Gabbro. Yes, the same dark rock you saw at the first stop!

At stop 2 you were asked what could have caused the higher temperature metamorphism at the base of the gneiss. Well, here it is; the proverbial smoking gun.

The intrusion of this gabbro metamorphosed the gneiss. This lets you get a relative age of the two rocks. Since you already have the relative age of the light and dark rocks from stop 1 you can now give a relative age sequence to all three rocks. Not bad for a first outing in geology!

 Brett Dooley Website Maintained since 2011 Last Updated July 2019