Petroglyphs are created by chipping the black top layer (called desert varnish) off of rock by using another smaller stone. It is wonderful that these images have endured, despite the efforts to deface them and remove them.
150,000 years ago a string of volcanos west of Albuquerque erupted. Cinder cones from ancient volcanos are still visible west of what is now the city, and west of the escarpment.
A few of the cinder cones as viewed from the escarpment
Google satellite map image
A view of the escarpment from below
The images and symbols most likely had spiritual meaning. Some of the designs are similar to those used by present-day Indians, so the meaning of the symbols may be the same. Others are unique to the ancient people.
I'm thinking Ma and Pa Indian wanted the kids out of the teepee and told them to go out amongst the rocks and play! (OK, so, I'm kidding... but it coulda been true!)