Safety Warning: Be sure to carry enough food and water with you. Summer temperatures easily exceed 100 degrees and there is a good 1500 foot elevation gain with no shade.
At this location, look north down into the valley. There is a stand of green trees near the bottom of the valley. These trees mark the approximate location of the Cahlone Creek Fault. These trees thrive because the fault impedes the flow of ground water and forces up to the surface in springs.
On the west side of the fault, where you are standing, is the Pinnacles Volcanic Formation. On the east side, are the Temblor Fanglomerates made up of sedminentry material deposited in an alluvial fan.
It is thought that the Chalone Creek Fault was part of the San Andreas Fault until a large sandstone formation jammed the section. The current San Andreas Fault line moved about 5 miles east near highway 25.
Logging requirements:
Send me a note with :
- The text "GCPRZ1 Chalone Creek Fault – Precursor to the San Andreas" on the first line
- The number of people in your group.
- Describe the general shape of the stand of trees and how that shape relates to the orientation of the canyon.
The following sources were used to generate this cache:
- http://www.nps.gov/pinn/pphtml/subnaturalfeatures14.html National Monument Pamphlet, Pinnacles Geological Trail
Placement approved by the Pinnacles
National Monument