Petroglyphs are images created by removing part of a rock surfaces by incising, pecking, carving, and abrading. Petroglyphs are found world-wide, and are often (but not always) associated with prehistoric peoples. They are one of the three different techniques used in Rock art, the prehistoric precursors to art. The meaning of these works is still unclear, but much conjecture and speculation has been produced in academic circles.
Some petroglyphs seem to depict real events whilst many other examples are apparently entirely abstract. Some theories hold that they may have been a way of transmitting information, while other theories ascribe them a religious or ceremonial purpose. There are many common themes throughout the many different places that the petroglyphs have been found; implying the universality of purpose and similarity of the impulses that might have created the imagery. The phenomenon is thought by many to be the foundation of art as well as an indication of the development of cognitive and abstract ability in the evolution of humankind, as most was created before the advent of the first major civilizations. While we may not understand their purpose, we can appreciate and enjoy the beauty of petroglyphs, admiring the creativity of those from long-ago eras.
The word petroglyph comes from the Greek words petros meaning "stone" and glyphein meaning "to carve" (it was originally coined in French as pétroglyphe).
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 twentieth 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.
Petroglyphs are from removing rock in such ways as scratching, abrading, pecking, carving, drilling, incising, and sculpting. Locations of choice are rock facets coated with patina, a dark mineral accumulation on rock surfaces. Petroglyphs remove the patina, exposing the contrasting lighter rock interior. Instances of negative images, produced by removing the patina surrounding the intended figure, are also known. Sometimes petroglyphs are painted or accentuated by polishing. The degree of repatination indicates relative dating. Some of the most ancient petroglyphs are the same color as the surrounding rock.
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." 
Some petroglyph images probably had deep cultural and religious significance for the societies that created them; in many cases this significance remains for their descendants. Many petroglyphs are thought to represent some kind of not-yet-fully understood symbolic or ritual language. Later glyphs from the Nordic Bronze Age in Scandinavia seem to refer to some form of territorial boundary between tribes, in addition to possible religious meanings. It also appears that local or regional dialects from similar or neighboring peoples exist. The Siberian inscriptions almost look like some early form of runes, although there is not thought to be any relationship between them. They are not yet well understood.
Some researchers have noticed the resemblance of different styles of petroglyphs across different continents; while it is expected that all people would be inspired by their surroundings, it is harder to explain the common styles. This could be mere coincidence, an indication that certain groups of people migrated widely from some initial common area, or indication of a common origin. Other theories suggest that petroglyphs were made by shamans in an altered state of consciousness, perhaps induced by the use of natural hallucinogens. Many of the geometric patterns (known as form constants) which recur in petroglyphs and cave paintings have been shown to be "hard-wired" into the human brain; they frequently occur in visual disturbances and hallucinations brought on by drugs, migraine, and other stimuli.
There are many famous sights of petroglyph works in Africa. Tassili n'Ajjer in Algeria is noted for its prehistoric rock paintings and other ancient archaeological sites, dating from neolithic times when the local climate was much moister, with savannah rather than desert. The art depicts herds of cattle, large wild animals including crocodiles, and human activities such as hunting and dancing. The art has strong stylistic links to the pre-Nguni Art of South Africa and the region, executed in caves by the San Peoples before the year 1200 C.E.
Akakus, Libya was inscribed as a UNESCO World Heritage Site in 1985 because of the importance of its rock paintings and carvings. The art dates from 12,000 B.C.E. to 100 C.E. and reflect cultural and natural changes in the area. There are paintings and carvings of animals such as giraffes, elephants, ostriches, and camels, but also of men and horses. Men are depicted in various daily life situations, for example while making music and dancing.
The ancient city of Wadi Hammamat in Qift, Egypt has many carvings and inscriptions dating from before the earliest Egyptian Dynasties to the modern era, including the only painted petroglyph known from the Eastern Desert and drawings of Egyptian reed boats dated to 4000 B.C.E.
Other important sites in Africa include Bidzar in Cameroon, Bambari, Lengo, and Bangassou in the south of the Central African Republic; Bwale in the west, Niola Doa in Chad, the Niari River valley in the Congo, Ogooue River Valley in Gabon, Jebel Uweinat in Libya, the Draa River valley in Morocco, the Twyfelfontein in Namibia, and life-size giraffe carvings on Dabous Rock, Air Mountains, in Niger.
Murujuga, in Western Australia is a unique ecological and archaeological area since it contains the world's largest and most important collection of petroglyphs – ancient Aboriginal rock carvings some claim to date back as far as the last ice age. The collection of standing stones is the largest in Australia. The rock art numbers over a million petroglyphs and contains many images of the now extinct Thylacine (Tasmanian Tiger).
The Sydney Rock Engravings consist of carefully drawn images of people, animals, and symbols, in the sandstone around Sydney, New South Wales, Australia. Many thousands of such engravings are known to exist in the Sydney region, although the locations of most are not publicized in order to prevent damage by vandalism, and to retain their sanctity, as they are still regarded as sacred sites by Indigenous Australians. They are comparable to petroglyphs of Native Americans, yet have their own distinctive style which is unlike rock art found anywhere else in Australia.
There is also a famous petroglyph site at Arnhem Land / Kakadu National Park, in Northern Australia.
The diversity of Asia's geography and culture is mirrored in its quantity of petroglyphs. Hong Kong alone has eight significant sites: Tung Lung Island, Kau Sai Chau, Po Toi Island, Cheung Chau, Shek Pik on Lantau Island, Wong Chuk Hang and Big Wave Bay on Hong Kong Island, and Lung Ha Wan in Sai Kung
The Edakkal Caves in Wayanad, Kerala, in India date back to about 4000 B.C.E. These are not technically caves by rather a cleft or rift approximately 96 feet by 22 feet, a 30 foot deep fissure caused by a piece of rock splitting away from the main body. On one side of the cleft a rock weighing several tons has fallen over the fissure forming a roof. The carvings are of human and animal figures, as well as of tools used by humans and symbols, suggesting they were created by a highly civilized prehistoric people. The petroglyphs inside the cave are of at least three distinct types. The oldest may date back over 5000 years ago. Evidence indicates that the Edakkal caves had been inhabited at several different times in history.
The Bangudae Petroglyphs, in Korea are located in Daegok-ri, Ulsan, South Korea. This site of substantial engraved rock art was rediscovered in 1971 and was designated as the 285th National Treasure of South Korea on June 23, 1995. The petroglyphs sit in an isolated forested area almost completely enclosed by steep mountains adjacent to the Daegok-cheon River, a tributary of the Taehwa River. There are three major panels in an area measuring 3 m in height and 10 m in length. A number of panels with similar rock-art motifs have been found nearby at the Cheonjeon-ni site.
It is commonly thought that the petroglyphs (Kr. amgakhwa or bawi geurim, 바위그림) at this site depict the physical embodiment of the hopes and wishes of prehistoric people. In this case, the petroglyphs were made to wish for a successful hunt or an abundance of prey.
Other important sites include Chumysh River basin, in Khaszikstan, the Tamgaly on the Ili River, a World Heritage Site, the Yin Mountains in Inner Mongolia, the Rock art and petroglyphs in Northern Areas in Pakistan, and the Angono Petroglyphs of Rizal in the Philippines.
There are two famous sites of petroglyphs in South America. Cumbe Mayo in Peru is the site of the ruins of a Pre-Columbian aqueduct stretching approximately five miles in length. There are a number of petroglyphs on the aqueduct and surrounding caverns.
The Corantijn Basin, one of a number of archaeological sites in Suriname, contains a large number of petroglyphs. An interesting aspect of these petroglyphs is that they are all found near water. Unfortunately, though, the majority of these petroglyphs cannot be connected to specific prehistoric indigenous groups.
North America has more petroglyph sites than any other continent. A large cluster is located in the Southwestern United States, and are protected by National Park boundaries, such as Arches National Park and Capitol Reef National Park of Utah, Death Valley National Park, Lava Beds National Monument, Tule Lake, Maturango Canyon, and Coso Range, Northern Mojave in California. There are also sites in Arkansas, Washington, Michigan, and Ohio.
The Jeffers Petroglyphs site is an outcrop of rock in southwestern Minnesota with pre-contact Native American petroglyphs. The petroglyphs are pecked into rock of the Red Rock Ridge, a 23-mile (37 km)-long Sioux quartzite outcrop that extends from Watonwan County, Minnesota to Brown County, Minnesota. The exposed surface is approximately 150 feet (50 m) by 650 feet (200 m) and surrounded by virgin prairie. Several old wagon trail ruts traverse the site, one of which is believed to be the old stage coach route from New Ulm, Minnesota to Sioux Falls, South Dakota.
Petroglyph National Monument stretches 17 miles (27 km) along Albuquerque, New Mexico's West Mesa, a volcanic basalt escarpment that dominates the city’s western horizon. The 7,236 acre (29.28 km²) monument is cooperatively managed by the National Park Service and the City of Albuquerque. Petroglyph National Monument protects a variety of cultural and natural resources including five volcanic cones, hundreds of archaeological sites and an estimated 25,000 images carved by native peoples and early Spanish settlers. Many of the images are recognizable as animals, people, brands and crosses; others are more complex. Their meaning was, possibly, understood only by the carver. These images are the cultural heritage of a people who have long since moved into other areas and moved on through history. The monument protects them for visitors to see and appreciate for generations to come.
There are over 21,000 petroglyphs at the Three Rivers Petroglyph Site in Three Rivers, New Mexico, located midway between Tularosa and Carrizozo in Otero County. Many of the petroglyphs can be easily viewed from a trail open to the public which winds through the rocks for about one mile. The petroglyphs are thought to be the product of the Jornada Mogollon people between about 1000 and 1400 C.E. The site is protected and maintained by the Bureau of Land Management. The exact age of the petroglyphs is not known, but some atlatl symbols at Jeffers are a close match with similar symbols at Indian Knoll in Kentucky, which have been dated to 3000 B.C.E. These are probably the earliest petroglyphs at the site and indicate that the site was first visited during the Late Archaic Period. Another clue to the age comes from the projectile point carvings, which show a projectile point design used by hunters in the Late Archaic Period. Other carvings, such as thunderbirds, dragonflies, turtles, and shamans, are symbolic of later tribes such as the Otoe tribe, Sioux, and Iowa tribe. These are believed to date between 900 C.E. and 1750 C.E.
There are several sites in Canada, in British Columbia, Ontario and Nova Scotia. Petroglyphs Provincial Park, is situated northeast of Peterborough, Ontario, Canada. It has the largest collection of ancient First Nations petroglyphs in Ontario. The carvings were created in the pre-Columbian era and represents aspects of First Nations mysticism, including shamans, animals, and the Great Spirit. The sacred stone is generally believed to have been carved by the Algonkian people between 900 and 1400 C.E. Today, the First Nations people of Ontario call the carvings Kinomagewapkong, meaning "the rocks that teach" or "the Teaching Rocks."
There are also petroglyph sites at Mina, Nuevo Leon in Mexico.
Like North America, Europe hosts a number of petroglyph sites. Mercantour National Park in France, Newgrange in Ireland, the Vale do Côa rock carvings of Portugal, the Tanumshede (Bohuslän) of Sweden (which is also a World Heritage Site) and Kamyana Mohyla in the Ukraine all have petroglyph sites.
The Cup and ring marked rocks in Northumberland, England are unique among petroglyphs. They consist of a concave depression, no more than a few centimeters across, pecked into a rock surface and often surrounded by concentric circles also etched into the stone. Sometimes a linear channel called a gutter leads out from the middle. Where they are etched onto natural, flat stone it has been observed that they seem to incorporate the natural surface of the rock. Those at Hunterheugh are mostly connected to one another by gutters that can channel rainwater from one to the next, down the sloping top of the stone.
The site of Val Camonica, Italy is home to the greatest complex of rock drawings in sub-Alpine Italy, with approximately 350,000 petroglyphs drawn by members of the Camunni tribe on hundreds of exposed rocks dating from about 8000 B.C.E.; cosmological, figurative, and cartographic motifs are featured, in some locations forming monumental hunting and ritual "scenes." It includes also scenes of zoophilia.
The Rock carvings at Alta in Norway are located now at a World Heritage Site. Since the first petroglyphs were discovered in 1972, more than 5000 carvings have been found on several sites around Alta. The main site, located at Jiepmaluokta about 4 kilometers outside of Alta, contains around 3000 individual carvings and has been turned into an open-air museum. It is Norway's only prehistoric World Heritage Site. The earliest carvings in the area date to around 4200 B.C.E.; the most recent carvings are generally dated to around 500 B.C.E. The wide variety of imagery shows a culture of hunter-gatherers that was able to control herds of reindeer, was adept at boat building and fishing and practiced shamanistic rituals involving bear worship and other venerated animals. Apart from the visual evidence of the carvings themselves, not much is known about the culture that produced these carvings.
There are petroglyph sites in the Wadi Rum and Wadi Faynan of Jordan, made by many human cultures since prehistoric times, with many cultures—including the Nabateans—all of whom left their mark in the form of rock paintings, graffiti, and temples. The "Graffiti Rocks," about 110 km SW of Riyadh off the Mecca highway is another important petroglyph site in the Middle East.
Engravers from Val Camonica, Italy
Rock Carving in Tanum, Sweden
Carving "The Shoemaker," Brastad, Sweden
Petroglyphs at Orongo, Rapa Nui (Easter Island). A Make-make at the base and two birdmen higher up
All links retrieved April 17, 2015.
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