ZZYZX, CALIFORNIA–It is hard to believe that the Mojave region once had vast lakes, erupting volcanoes and a diverse mammalian fauna including camels and horses. The most important record of this time is the Barstow Formation (Miocene — about 15 million years ago). This unit contains river and lake sediments along with volcanic ash, all of which produce a diversity of colors leading to the name “Rainbow Basin” for the best exposures outside Barstow, California.
The Wooster geologists spent the morning with the Barstow Formation in Owl Canyon and Rainbow Basin. The highlights included a group analysis of dozens of rock specimens, a desert tortoise crossing the road, and meeting old friends Buzz and Phyllis Sawyer from Barstow.