Petroglyphs (also known as rock engravings) are symbolic images sculpted or engraved on the surface of rocks by removing material from its surface layer with instruments of superior hardness.
The term 'petroglyph' was created in France in the 19th century (as pétroglyphe) from two Greek words: the prefix petro- (from petra, πέτρα meaning stone, rock) and glýphō (γλύφω meaning engraving, carving or chiselling).
Together with the painted representations (known as rock paintings, cave paintings or pictographs), petroglyphs belong to the broadest general category of rock art.
The use of rock art as a form of communication dates back to the very remote times of the Upper Palaeolithic period, but it can also reach modern times in some cultures and places, such as - for example - Australia and the Amazon rain forest, even up to the moment of contact with Western culture.
Petroglyphs have been found on all inhabited continents, although they are especially concentrated in Africa, South America, North America (mainly in the southwestern United States), Siberia, Australia and Europe (Scandinavia, Spanish Galicia, Ireland and Italy).
Petroglyphs of the world
Petroglyphs of Peru
The best known archaeological sites with this type of rock art in the Peruvian territory are:
Alto de la Guitarra (Ascope, La Libertad)
Cerro Mulato (Chongoyape, Lambayeque)
Checta (Canta, Lima)
Chichictara (Palpa, Ica)
Chontayacu (Uchiza, San Martín)
Huancor (Chincha, Ica)
Lachay (Huacho, Lima)
La Pitaya (Huancas, Amazonas)
Los Boliches (Olmos, Lambayeque)
Llusk'ani (Macusani, Puno)
Pusharo (Manu, Madre de Dios)
Quebrada de las Piedras Larbradas (Huarmey, Ancash)
Queneto ( Queneto, La Libertad)
Samanga (Ayabaca, Piura)
San Francisco de Miculla (Pachía, Tacna)
Toro Muerto (Uraca-Corire, Arequipa)
Foto: Javiera Castro, https://www.flickr.com/photos/143933597@N06/35649455172
Techniques for making petroglyphs
Petroglyphs range from those engraved very shallowly (as small points that are not easy to distinguish) to those that are formed by grooves of several centimeters deep.
Petroglyphs can be created by using two types of basic techniques:
Percussion: it consists of hitting one stone against another to create grooves on the rock surface. This technique is similar to the current chisel and hammer technique.
Scratching: it consists of using the edge of a carved stone of higher hardness to scratch the surface of a stone of lower hardness.
Some petroglyphs may have been additionally smoothed out. The technique used consisted of polishing the surface of the rock by rubbing it with another stone or wet sand.
Ancient petroglyph makers may have used tools specially designed for this purpose (e.g. metal tools which they brought with them), but generally they used stone tools made on site.
Hypothetical reconstruction of the creation of the carvings
(Information Center - La Candelaria)
(Photo: Christine Stathers)
Rock art on a global scale shares many common features. This applies to both petroglyphs and rock paintings. One of them is that the landscape – as we commonly understand it today – was not depicted.
The environment was usually limited to its selected elements, mainly images of animals (zoomorphic motifs) and human figures (anthropomorphic motifs). Plants were rarely represented.
A large group among the rock art are also motifs that do not have clear equivalents in the visible world. Referred to as abstract or geometric motifs, they indicate that rock art depicted not only the realities of the visible world but also abstract phenomena or ideas. Research from various parts of the world clearly shows that rock art very often communicated symbolic content.
Artistic reconstruction: Creators of Toro Muerto petroglyphs (Information Center – La Candelaria)