Geology and Missiles

This morning we joined Steve and Jan for an 8:30 a.m. ranger-led geology walk at the Door trail just north of the Visitor Center in the Badlands. The group was large, even at that early hour. We were actually glad to be out early, since the weather was moderate compared to what we might encounter in the afternoon.

The ranger gave us an introduction to the geology of this unusual area. It was formed differently than much of the terrain we have seen in the western parks. Although there are peaks, the Badlands formations are hot hills or mountains--they are erosional features. Instead of being upthrust or formed by volcanic action, the unusual formations here have been shaped by 500,000 years of mostly water-caused erosion. This is all the more surprising since there is very little water here. Evidently the Cheyenne River was once much faster flowing and larger than it is now.

Some of the formations pose mysteries even for geologists. For example, some of the sandstone is penetrated by "wormholes." The currently favored explanation is that these are trace fossils left by decayed plant roots. Another is that there are clastic dikes--the sort of formation usually found when volcanic material fills cracks--only this material is not volcanic.

After the walk, we decided to go home and cool off until after lunch. Then we went to the South Dakota Air and Space Museum at Ellsworth Air Force Base and took the base tour. The highlight of the tour is a visit to a Minuteman II Missile silo.

In the evening, we taught Jan and Steve how to play Farkel. They must have picked it up pretty quickly, since they each won a round. We went outside to watch the sunset--they have spectacular ones over the desert here. Ken took this photo looking east just after sunset.

It has been really great to have this chance to visit with Steve and Jan and have them take us around to many places we would never have found on our own. We'll miss them when we take off tomorrow for Hot Springs and the Black Hills Wild Horse Sanctuary.