This Earthcache is located at Del Valle Regional Park. This is a Day Use area.
Please visit their website for important information about hiking there.
Del Valle Regional Park
The Livermore Valley and surrounding hills were formed as a result of tectonic forces between the Calaveras fault to the west and Greenville fault to the east. These faults are branches of the myriad of faults that are near the boundary between the North American and Pacific tectonic plates.
Millions of years ago, in the Miocene age, extensional (stretching) forces resulted in rotation of the blocks between the faults, creating hills and troughs. The erosion of the variety of rocks that make up the Franciscian Complex created sediments of small rocks, sand and clay, and filled these troughs.
Following this period of extension, compressional forces acted on the area, resulting in broad folds on the surface. Through the Pleistocene and Holocene, over the last 5 million years, erosion during the series of Ice Ages created the topography we see today.
One dramatic example of this erosion can be see at the given coordinates. Here you can see many layers of sediment that were layed down millions of years ago.
To log this cache, please observe the exposed sedimentary layers and provide the following information in an email or message to the Cache Owner. Please do not post the information in a log to this cache page:
1. Identify this cache: GC92VYF Del Valle Erosion.
2. Names of the cachers.
3. Count the number of sedimentary layers that you can distinguish.
4. Find the darkest of these layers. Estimate the thickness of this layer and estimate the size of the largest rocks within this layer.
5. Find a place where you can see how the layers are tilted. Estimate the angle of tilt where horizontal is zero degrees.
6. Not required, but a picture of your party at the posted coordinates is greatly appreciated.