This dike was formed from underground faults and intersecting joint lines and can be found in many areas at Joshua Tree National Park. This photograph was taken across the road from the area known as Jumbo Rocks. Some information about Joshua tree: As erosion worked its way through this area it caused intusive splitting of the rocks which have become known as joints or dikes. Good examples of the joint system may be seen at Jumbo Rocks, Wonderland of Rocks, and Split Rock. Flash floods were believed to have caused erosion as they washed away the surface and left huge boulders which settled on top of each other. These are known as rockpiles. If you look carefully you can find a rockpile with a dike line like the one in this photograph and Joshua Tree National park has great expansive views making it very easy to create a nice photograph.
Photograph taken with a Canon Elan, 20mm lens, f22