These are a series of wind caves in the Anza Borrego
Desert. The dirt road to the trailhead goes through Split
Mountain Gorge that is periodically filled by flash floods, so
check the weather before attempting.
The shallow caves at this location have been eroded into the
sandstone mostly by water despite their name as wind caves. The
individual grains of sandstone are held together by various forms
of natural cement (not exactly like the artificial cement, but it
does the same thing). Like all natural systems, the cementation in
the sandstone is not perfectly uniform throughout the entire
formation. This natural cement dissolves slowly in water.
So when the infrequent rains in the area flow across the
sandstone, the rainwater slowly dissolves the cement freeing the
individual sand grains to be transported away by the rain or wind.
The areas that have less cementation erode just a little faster
than the surrounding rock forming depressions.
These depressions then erode even faster since the backs of the
depressions are shaded allowing water to remain on the surface of
the sandstone longer, dissolving the cement faster than the part of
the rock in the sun. This cycle continues, deepening the depression
into a cave.
Over the course of the entire year, the south side of the rocks
receive the most sunshine while the north side gets a little more
shade. For the logging requirement you will compare the depth of
south facing caves to north facing caves.
Logging requirements:
Send me a note with :
- The text "GCZ68N Wind Caves - Anza Borrego SP" on the first
line
- The number of people in your group.
- compare the relative depth of 2 south facing caves to 2 north
facing caves.
The following sources were used to generate this
cache:
- Geology of Torrey Pines State Reserve By Don
Grine, Geophysicist Emeritus, Torrey Pines State Reserve 2006,
http://www.torreypine.org/geology/geology.html#rock