Although it hard to see the reddish basalt volcanic rock in this photograph, if you look hard, you can see it. It's the light magenta area of profound erosion. It's the darker area just below the wire. If you visit the site, you can really see the volcanic red pumice like rock and basalt. The colors of the rock are seen with the human eye more than with an average camera and lens. At the time of this photograph, I was with young children, and didn't want to take them in tow across the desert brush to take a closer look. I am going back, though, and studying this young volcanic system.
This picture better shows a light band, and then below blackish volcanic basalt. This is a bowl like formation that requires more study indeed!
For fun, go into Google Earth, type in 'Mission Creek Reserve, CA' and explore the oasis and formations in the area. Click on the blue photo icons and look at the photos. Then wonder to the west and look at White Water, and then to the east to look at Joshua Tree National Park. Next, Google 'White Tank granite', read, then Google 'young volcanos, Joshua Tree National Park' and read up on that. That should keep you curious and amazed for a few hours. And then physically come on out and Visit Joshua Tree National Park, and it's surrounding reserves! The desert is amazing, with it's bare naked rocks!