Ranger Sarah observes the effects of Natural Forces on the rock. Freeze thaw cycles, erosion, plant and tree roots and lichens all work to break apart the rocks.
— at Pipestone National Monument.

Ranger Sarah continues hiking along the Sioux Quartzite Outcroppings. Sioux Quartzite is one of the world’s oldest rocks (over 1.6 billion years old) and is found throughout southwest Minnesota and southeast South Dakota.
— at Pipestone National Monument.

The rock wall along the trail is Sioux Quartzite, which overlies the pipestone. Since the rock layers slope 8° downward from the quarries near the Visitor Center to the cliffs where you’re standing, the pipestone layer would be roughly 100 feet underground at this point.
— at Pipestone National Monument.

Ranger Sarah hikes along the Sioux Quartzite outcroppings. Lichens can be seen on the rocks. Lichens may spread over the entire surface at a rate of an inch or less per century and live for thousands of years. They currently cover approximately 8% of the Earth’s surface.
— at Pipestone National Monument.

Ranger Sarah approaches the Sioux Quartzite outcroppings which are nearly 20 feet high, while hiking the circle trail.
— at Pipestone National Monument.