Joshua Tree National Park

This year, while in Los Angeles for Christmas, Eric and I decided to visit Joshua Tree National Park. This park covers two distinct deserts: the Mojave Desert and the Colorado Desert, and the transitional zone between them. The area is also located right next to the San Andreas fault, and has experienced significant uplift. The park is filled with magnificent rock formations where magma pushed up through the surface.

Interestingly, although the two deserts are adjacent to each other, they feature very distinct wildlife and vegetation.

The Mojave Desert is a "forest" of Joshua Trees.

The individual trees look like this.

The Colorado Desert is characterized by these cholla cacti.

The individual cholla cactus looks like this.

The park features truly great geologic diversity as well. It was odd to see snow in the desert, but there it was.

The park is filled with strange and wonderful rock formations. Most of these are caused by uplift and by magma rising through the surface.

Most of these are from the Hidden Valley area.

This rock is an example of one of the major geologic features of the park. The park is full of older rocks called Pinto gneiss (pronounced "nice"). But magma, in a form called monzogranite, rose up and intruded into the Pinto gneiss. The monzogranite then cracked the Pinto gneiss when it cooled, creating the vertical lines (and some of the horizontal ones) you see in this rock. You can get a sense of the size of the formation by noting the climbers on top.

This one is from the Geology Tour Road. The Geology Tour Road would definitely have been better with an SUV, so we could have gone up into the mountains. Also, the stops were very poorly signed. Otherwise, the scenery was great.

This one is called Skull Rock.

All of this marvelous geologic diversity arises partially because of the park's proximity to the famous San Andreas fault, which separates the North American plate from the Pacific plate. What, you thought Los Angeles was in North America? We could see the fault itself from this lookout point. It's the dark fissure that cuts across the frame.

From the same lookout point, we could see the Salton Sea.

The park provides great opportunities for seeing birds. We heard, and then spotted, this ladderback woodpecker.

Last updated: 12/30/2008 by Eric and Beth Zuckerman