Please obey all park rules and regulations, there is no reason to leave the path for this Earthcache.
1. These rock formations are part of the Vazquez formation and it’s a thick deposit of sandstone layers deposited down through millions of years. Close to 25 million years! These deposits came from nearby San Gabriel Mountains. Weather and pressure cause the sand to compact and form the flat layers you see. If you look close you can see each year’s layers. Depending on how crazy the storms were you can see some layers of conglomerates that contain very small rocks and others that contain larger rocks/boulders.
2. These steep formations are caused by the effects of the Elkhorn fault (an offshoot of the well-known San Andreas Fault) reacting with the Vasquez formation. The angles sometimes are over 45 degrees!
3. The wind, rain and cold (freezing) all help create these wonderful formations.
4. Rivers running along sandstones like this sometimes you see holes getting worn out by rocks caught up in curves in the path and harder rocks getting hung up in these curves and wearing away the rock.
5. Tafoni are ellipsoidal, pan to bowl shaped, natural rock cavities. These sometimes develop both on inclined or vertical surfaces and occur in groups. They include pits, hollows, niches, little or big recesses, and honeycomging. a. Visors associated with large tafoni are overhanging shelves that look like awnings on your house. Tafoni’s are mostly formed by ocean spray onto the surface of these rocks, this ocean spray contains salt. These small particles work and wear themselves into small cavities and wear on the rock they’ve landed on by drying out and growing thus expanding and breaking the surrounding rock. This continues and continues till you see cavities or honeycombing within the rock surface.
6. The local Indians, the "Tataviam” used these formations to live in and around in. Any of you that have been up here in bad winds, know what the small sandstone grains do to your hand and face. You can image what millions of years of this can do.
These rocks are named after the infamous California bandito “Tiburcio Vazquez”
So, the questions are:
1. What process or processes came into play with this example of sandstone?
2. Do you see Honeycombing? How many small cavities are together in one place?
3. Is this a Visor?
4. What is the smallest and largest size cavity you see?
5. What is your estimate on the angle of any of the rocks around you?
6. Type GC7GKBC Tafoni at Vazquez Rocks and how many people were with you today.
Used for reference:
- https://pubs.usgs.gov
- U.S. Department of the Interior, Professional papers and Geological surveys
- Wikipedia
- WWW.Tafoni.com
- History of Vazquez Rocks and the Aqua Dulce History project