Geology Photos, Day 3 - Quartz Arenite

Evelyn's got a really cool picture of a coral "boulder." But when they're that sized, do they really qualify as boulders? And what if it's cemented to the material beneath it? Is it just a pinnacle? Although since we're all travelers on a little blue pebble, perhaps one needs to acknowledge the context and worry less about specific descriptors of scale...



Today's picture is of some quartz sand. But not just any sand. This sand is from a block of disaggregated sandstone of the Wonewoc Formation and is an excellent example of a texturally and compositionally "mature" sand. This stuff has been knocking around long enough that almost all of the other minerals that one finds in "sand" have weathered away. This particular sandstone is typically over 95% quartz - allowing us to call the sandstone as a quartz arenite. Another cool word.

One of the reasons petroleum production companies are interested in mining this sand is its purity. Also, the smooth, round grains behave well in hydro-fracking development.