Petroglyphs are
images created by removing part of a
rock surface by incising, pecking, carving, and abrading. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions of the technique to refer to such images. Petroglyphs are found world-wide, and are often (but not always) associated with
prehistoric peoples. The word comes from the
Greek words
petros meaning "stone" and
glyphein meaning "to carve" (it was originally coined in
French as
pétroglyphe).
The term petroglyph should not be confused with pictograph, which is an image drawn or painted on a rock face. Both types of image belong to the wider and more general category of rock art. Petroforms, or patterns and shapes made by many large rocks and boulders over the ground, are also quite different. Inukshuks are also unique, and found only in the Arctic (except for reproductions and imitations built in more southerly latitudes).
The oldest petroglyphs are dated to approximately the Neolithic and late Upper Paleolithic boundary, about 10,000 to 12,000 years ago, if not earlier (Kamyana Mohyla). Around 7,000 to 9,000 years ago, other precursors of writing systems, such as pictographs and ideograms, began to appear. Petroglyphs were still common though, and some cultures continued using them much longer, even until contact with Western culture was made in the 20th century. Petroglyphs have been found in all parts of the globe except Antarctica with highest concentrations in parts of Africa, Scandinavia, Siberia, southwestern North America and Australia.
There are many theories to explain their purpose, depending on their location, age, and the type of image. Some petroglyphs are thought to be astronomical markers, maps, and other forms of symbolic communication, including a form of "pre-writing". They might also have been a by-product of other rituals sites in India, for example, have been identified as musical instruments or "rock gongs". [1]
