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'Water' caves, not wind caves
Mt. Diablo State Park is famous for its stunning sandstone formations, also known as 'tafoni." Although commonly referred to as "wind caves," the element most responsible for creating these formations is water. Mt Diablo is probably only 2 million years old at the most, and the caves are only a few hundred or thousand years old. Geologically speaking, the porous sandstone in which these caves form can't stand up to our Mediterranean climate of wet winters and dry summers for long.
On tafoni structures, you can often see a dark mineral crust called a duracrust. This is what remains of the mineral cement that holds the sandstone together. Brought out by capillary action as rainwater evaporates, it's then deposited on the outside of the rock. When the duracrust falls off, the sandstone underneath erodes rapidly.
To log this cache, you will need to complete the following:
- Email the cache owner the (a) What is the term for the weathering process that created the formations? and (b) Describe the texture of the tafoni.
- Post a picture of You and your GPS along with the Wind Cave.
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