The Work of Wind and Deserts - The Changing Earth: Exploring Geology and Evolution - page 393

Geo-inSight

Rock Art for the Ages

Rock art includes rock paintings (where paints made from
natural pigments are applied to a rock surface) and
petroglyphs (from the Greek petro, meaning "rock," and
glyph, meaning "carving or engraving"), which are the
abraded, pecked, incised, or scratched marks made by
humans on boulders, cliffs, and cave walls.
Rock art has been found on every continent except
Antarctica and is a valuable archaeological resource that
provides graphic evidence of the cultural, social, and religious
relationships and practices of ancient peoples. The oldest
known rock art was made by hunters in western Europe and
dates back to the Pleistocene Epoch. Africa has more rock art
sites than any other continent. The oldest known African rock
art, found in the southern part of the continent, is estimated
to be 27,000 years old.
Petroglyphs are a fragile and nonrenewable cultural
resource that cannot be replaced if they are damaged or
destroyed. A commitment to their preservation is essential
so that future generations can study them, as well as enjoy
their beauty and mystery.

In the arid Southwest and Great Basin of North
America where rock art is plentiful, rock paintings and
petroglyphs extend back to about 2000 B.C. Here, rock
art can be divided into two categories. Representational
art deals with life-forms such as humans, birds, snakes,
and human-like supernatural beings. Rarely exact
replicas, they are more or less stylized versions of the
beings depicted. Abstract art, in contrast, bears no
resemblance to any real-life images.

1. Various petroglyphs exposed at
an outcrop along Cub Creek Road in
Dinosaur National Monument, Utah.

2. A human-like petroglyph, an example of
representational art, exposed at an outcrop
along Cub Creek Road in Dinosaur National
Monument, Utah. Note the contrast between
the fresh exposure of the rock where the
upper part of the petroglyph's head has been
removed, the weathered brown surface of the
rest of the petroglyph, and the black rock
varnish coating the rock surface.

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