Monday, January 23, 2006

Petroglyphs 4: Snakes or rivers? Posted by Picasa
Petroglyphs 3: Many and varied flavors Posted by Picasa
Petroglyphs 2: Critters Posted by Picasa
Petroglyphs 1: Human figure

These are from Deer Valley, north of Phoenix. There are reported to be about 1500 different images on these rocks. The images are almost all created by hammering away the desert varnish to expose the light-colored stone underneath. By measuring how much varnish has accumulated since the image was created, scientists can do both relative dating (more varnish is older) and a guestimate at total age (at least a thousand years plus, for the oldest).

The site is sacred to several current tribes and the park is designed to limit access and vandalism while allowing education. Posted by Picasa