Parks & Public Lands - Barstow:
Rainbow Basin
Geology of Rainbow Basin and Owls Canyon
Rainbow Basin and Owls Canyon are two destinations near Barstow, California, renowned for their colorfully painted rock formations and interesting geological aspects. Both sites are expositions to the strength of natural forces like earthquakes and volcanic actions, which have sculpted the earth over a million-year timeframe. The rocks and faults here tell stories about shifting earth, ancient lakes, and the slow process of time.
Area Faults
Faults are fractures in the Earth's crust where the ground has moved. Multiple faults in both Rainbow Basin and Owl Canyon have allowed the land to break up and move over time and account for the rugged topography seen today. Some of the significant faults in the area include:
Owl Canyon Fault:
This fault slices through Owl Canyon and is responsible for breaking up the land in this area, shifting it into the form you see today.
Waterman Fault:
Another important fault in the Rainbow Basin is where movement along the fault has caused the folding and bending of rock layers, which is why you see so many angles in the rock layers.
Barstow Fault:
This fault lies near the Barstow Syncline and plays a vital role in land formation by moving rock layers up and down.
Mojave Block Faults:
The entire region is a part of the Mojave Block, which comprises many smaller faults. These more minor faults, even unnamed, cause shifts in the lands, twisting the rock layers in different directions.
Formation of Rocks
The rock formations in Rainbow Basin and Owl Canyon give a glimpse into the Earth's past. They are made of rocks formed from volcanic activity and deposits of ancient lakes. Here are some of the key formations:
Barstow Formation:
This several million-year-old rock unit, dating back to the Miocene Epoch, stands out as the most significant in age and importance. It consists of tuff-igneous rocks formed from compacted volcanic ash-sandstones and sediments deposited by ancient lakes. The Barstow Formation is also very renowned for containing ancient animal fossils.
Mud Hills Formation:
The Mud Hills Formation adds to the beautiful multicolored layers seen in the area. It comprises both volcanic and sedimentary rocks, which indicate the diverse variety of environments the area once experienced.
Fossil Canyon:
Though it is not a formation, it is a place that exposes the rock layers containing the fossils. It gives geologists a lot of information about life in this area from millions of years ago. Coon Canyon: Like Fossil Canyon, Coon Canyon exposes rock layers and formations indicative of clues to the geological past of the area. Syncline: The Barstow Syncline
A syncline is a fold in the Earth's crust that always bends downward. The structure of rock layers has folded downward into a sort of trough shape. One of the more notable geomorphological features within the area of Rainbow Basin is the Barstow Syncline. With this great bowl-shaped fold, it is a piece of land that has been pushed and folded for millions of years. This is an excellent example of how powerful tectonic forces have shaped this area.
Conclusion
Rainbow Basin and Owl Canyon are just about one big natural classroom exposing how the forces of Earth have shaped and molded the landscape throughout millions of years. The various faults and rock formations here tell a tale of ancient lakes, volcanic outbursts, and the sluggish movement of the crust of Earth. For a geologist or an outdoor enthusiast, visiting the Rainbow Basin is one great way to become much more sensitive to the history written into the rocks.
