Atlatl Rock Petroglyph

Provided by: Carl Crumley
Summary author: Carl Crumley

The photo above shows one of the ancient Native American drawings on Atlatl Rock in the Valley of Fire State Park, Nevada. Unfortunately, also visible is some modern graffiti.

An ancient sea covering this area resulted in sedimentary deposits that today are visible as red sandstone formations, after eons of geologic upheaval and erosion. The sandstone rocks often take on a dark covering called desert varnish. Desert varnish is a thin coating of manganese, iron and clays on the surface of sun-baked boulders that's formed by colonies of microscopic bacteria living on the rock surface. The bacteria absorb trace amounts of manganese and iron from the atmosphere and precipitate it as a black layer of manganese oxide, or reddish iron oxide, on the rock surfaces.

Native American petroglyphs were pecked, scratched or ground into the surface of the rock. The current theory of the origins of these drawings date them to about 4,000 years ago and were likely made by an Atlatl Shaman, an individual who evidently specialized in the treatment of spear wounds.

Related Links:

• Valley of Fire State Park
• Glossary of Geologic Terms
• About Sandstone
• Desert Varnish
• More About Atlatl Rock

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