Tuesday, October 28, 2014

Week 7: Metamorphic Rocks

Metamorphic rocks occur in the canyons nearby my home. As I hike through Battle Creek Canyon, just East of Pleasant Grove, I see slate everywhere. This indicates that shale has been exposed to low-grade metamorphism. The convergent plate boundary nearby must have caused regional metamorphism to occur below the surface. Through millions of years of erosion from water and wind, this metamorphic rock is not accessible.

Slate, a metamorphic rock, is commonly used for floor and roof tiles, because it has parallel lines of weakness that make it easy to split into smooth slabs. Marble is also used as a high-class addition to many homes, commonly as bathroom tile and countertops and columns. As evidenced below, metamorphic rocks are also commonly used as gravestones.

This gravestone appears to be made of a kind of migmatite--igneous and metamorphic rock mixed. You can tell by the dark and light pods and layers.

This gravestone appears to be made of marble, a rock made of metamorphosed limestone.

This gravestone is another that appears to be made of marble.

The three gravestones above were found at the Pleasant Grove Cemetery, located at 100 East 400 South in Pleasant Grove.

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