About the Site
Joshua Tree National Park (2)  


Park History

Joshua Trees

Rock Piles

Colorado Desert

Plants of Colorado


Mojave Desert

Plants of Mojave


Keys View

Lost Horse Valley

Quail Springs

West Entrance




Rock Piles

One of the remarkable aspects of the park is the existence of hills known as rock piles. These are found throughout the upper section of the park, as in the picture below taken along Park Boulevard near the northwestern entrance to the park.

Another view of rock piles and a section of the Mojave Desert is shown below.

These rock piles are made up of a pinkish monzogranite, which can be appreciated in the picture below. Some of the most intereresting areas are those in which the rock piles form a steep cliff, with a number of Joshua trees growing in its shadow.

The pinkish rocks contrast beautifully with the green vegetation of the high desert.

These rocks make for excellent areas for climbers to test their rock climbing skills. Joshua Tree National Park is an extremely popular site for rock climbers. The rock below near Hidden Valley is one of the favorite places for climbers in the park.

Another view of rockpiles is shown below.

The rocks found in rockpiles are formed within the earth when molten rock cools and hardens. Water seeps into the subsurface joints. Because of the reduction of surface pressure, uplift, and erosion, the rocks are later pushed above the ground where they are are subject to other erosive forces.

Some of the piles consist of smaller rocks, such as the ones shown in the next photograph and the one beyond that. These hills have the appearance of a pile of rubble.

Here is another of the hills which look like giant piles of gravel.

The giant rock piles are reminiscent of a variety of objects. Many look like castles or forts.

For those who have grown up watching cowboy and old West television shows, these giant rock piles can really remind them of those settings. This hill is found near Keys View Junction road.

In many ways the rock piles are as emblematic of the park as the Joshua tree plants.

The Joshua trees look particularly interesting when a giant rock pile serves as a backdrop.

Here are more rock piles setting off the desert vegetation.

After the masses of molten rock were pushed up beyond the surface, they cooled. Eventually, the rocks expanded and broke along approximately parallel cracks. These cracks are called joints. Additional erosion results in the characteristic appearance that looks like masonry walls.

One of the loveliest sights in the park is the visual effect of the setting sun on the surface of the rock piles when the pinkish surface of the rocks gives way to a golden glow.

- Next Page for Joshua Tree National Park -

  • All photographs ©Patrick Holleran, Shannon Digital Imaging, 1994-2013

  • Commercial use of the images contained in this document without express written consent is strictly prohibited.

  • Comments and other remarks can be sent via e-mail to parkvision@shannontech.com