Sylvan Lake Geology in the Black Hills of South Dakota

July 6 through 13, 2009

Sylvan Lake in the Black Hills of South Dakota.

We spent some time today at Sylvan Lake in the Black Hills of South Dakota. Sylvan Lake is one of the places you should visit when in the Mount Rushmore area. You should also plan to do the Needles Scenic Highway, Needles Tunnels, Iron Mountain Road, and Custer State Park when in the Black Hills.

We are camped near Custer State Park and the town of Custer in the southern part of the Black Hills at Custer's Gulch RV-Park. It is an OK commercial campground just like dozens of others in this area.

Sylvan Lake in the Black Hills of South Dakota

This large exposure of granite is protruding from Sylvan Lake in the Black Hills of South Dakota.

Sylvan Lake and the granite dam in the Black Hills of South Dakota

This is granite dike on the back side of Sylvan Lake in the Black Hills of South Dakota.

One day we walked behind these dikes.

When visiting Sylvan Lake make sure to take time and enjoy the walk around the lake. There are some impressive formations on the back side of the lake.

Macklyn Fairchild posing with granite spires at Sylvan Lake in the Black Hills of South Dakota

Our friend, Macklyn Fairchild, looking back at me as we circle behind those granite spires at Sylvan Lake in the Black Hills of South Dakota.

Sylvan Lake Granite exposure at Sylvan Lake in the Black Hills of South Dakota

You can see the course texture on these dikes of granite indicating they cooled slowly while still underground.

The the rate at which molten rock cools creates different rocks. Slow cooling under great pressure creates a course texture.

Sylvan Lake in the Black Hills of South Dakota

A picture of Sylvan Lake taken from behind a pine tree.