#thin section thursday

When sand has traveled a long way from the rocks where it was generated, like when it has washed down all the way to a beach, the actions of the waves will round the grains and wear down sharp edges. These sand grains are quite angular and poorly rounded, so they can’t have traveled far.

Sand grains also can be easily sorted by size and grain type when they’re washed downstream; these grains contain a number of different sizes and minerals, again suggesting this sand was collected close to the rocks that sourced them.

You also can see some organic material, cellular plant matter, mixed in with these sand grains.

Just by scooping up the sand in an area, you can often piece together the geologic processes involved in creating it, and it makes a good photo on top of that.

Full image is around 1 mm across. This image was taken under crossed-polarizers conditions (possibly slightly off of that given the violet background).

-JBB