Pictographs
Most pictographs are found on light-colored rock surfaces in protected areas such as caves, rockshelters or beneath overhangs protecting them from the weather. The two colors used to create pictographs within Great Basin National Park were shades of red (the most common color) and black. The various shades of red were almost always made from iron oxide hematite (ocher) while the black colors came from charcoal.

In order to make the paint, the mineral was ground into a fine powder and mixed with a binder. The type of binder varied from place to place depending upon availability. Types of binder included animal and vegetable oils, blood, and whites of eggs.

Applying the paint to the rock surface was done in several ways, including using frayed twigs, small bundles of stiff grass, pointed sticks, and fingers.

Petroglyphs
Petroglyphs are frequently found on rocks composed of limestone, sandstone, granite, or volcanic basalt. Within the park, petroglyphs are found on limestone rocks. These rock types, especially in desert regions, have dark patination occurring on the surface due to the exposure of the elements (sun, wind, rain, snow). When this patination is removed, it creates a contrast between the dark outer layer and the lighter, newly exposed rock underneath.

The main method used when making petroglyphs was pecking. This was done by either using a hammer stone, which created rough outlines with a shallow design, or the use of a stone chisel along with the hammer stone to create finer, more controlled lines. Scratching a design on the rock surface was also used. This created a very shallow design.

Now that you know the difference between pictographs and petroglyphs along with how they were made, you're probably asking yourself, "What do all those designs (lines, circles, zigzags, dots, animal and human-like figures) mean?" Good question. When it comes to the interpretation of rock art drawings, the only person who knows the full meaning behind the drawings (if there is a meaning) is the artist himself. Because of this, archeologists can only document the site with photos, drawings and descriptions.

Protection of Rock Art
When I talk about the protection to rock art sites, I'm not talking about protecting the sites from the natural elements like the sun, wind, rain, or snow. These elements are a natural process and cannot be controlled. What I'm talking about is the protection from human impacts. When looking at rock art you may not see that it is very fragile and can be destroyed in a very short time. Yes, the natural impacts upon rock art are also destroying it, but this process can take hundreds if not thousands of years. The human impact can be within minutes. These impacts include: outlining the drawings with paint, chalk, crayons, or graphite (pencil); graffiti; touching (touching pictographs can rub the pigment off); and even breaking off a drawing. These are all destructive acts that not only take away the history of the area but are a Federal offense.

So when hiking around Great Basin National Park, or another National Park, Forest Service or Bureau of Land Management land, and you come upon a rock art site, congratulations, you have found a bit of history. Hopefully the only thing you will take is pictures, so that the next person to come along will also be able to enjoy the history of the area.

JoAnn Blalack is the cultural resource manager at Great Basin National Park.