Geoglyphs - Worldwide Ancient Art of the Landscape

Desert Ground Drawings, Effigy Mounds, and Geometric Shapes

The Uffiington Horse Geoglyph, Oxfordshire, England
This 365-foot-long (111 m) silhouette of a horse carved into the chalky side of a hill in the county of Oxfordshire, west of London, stands out clearly downhill from the ruins of Uffington castle. HOPE PRODUCTIONS/Yann Arthus Bertrand / Getty Images

Geoglyph is a word used by archaeologists and the public to refer to ancient ground drawings, low relief mounds, and other geometric earth and stone work found in isolated places throughout the world. Functional purposes attributed to them are almost as varied as their shapes and locations: land and resource markers, animal traps, cemeteries, water management features, public ceremonial spaces, and astronomical alignments.

Geoglyph is a new word and doesn't show up in many dictionaries yet. Diving deep into Google Scholar and Google Books, you'll find that the term was first used in the 1970s to refer to gravel ground drawings at the Yuma Wash. The Yuma Wash drawings are one of several such sites found in desert locations in North America from Canada to Baja California, the most famous of which are the Blythe Intaglios and the Big Horn Medicine Wheel. In the late twentieth century, the term specifically meant ground drawings, especially those made on desert pavements (the deserts' stony surface): but since that time, some scholars have broadened the definition to include low-relief mounds and other geometric-based constructions.

What is a Geoglyph?

Geoglyphs are known across the world and vary widely in construction type and size. Researchers recognize two broad categories of geoglyphs: extractive and additive and many geoglyphs combine the two techniques.

  • Extractive geoglyphs (also called negative, "campo barrido" or intaglio) involves scraping away of the top layer of soil on a piece of land, exposing contrasting colors and textures of the lower layer to create designs
  • Additive geoglyphs (or positive or rock alignments) are made by gathering materials and piling them on the soil surface to create the design

    Extractive geoglyphs could include the Uffington Horse and the Cerne Abbas Giant (a.k.a. the Rude Man), although scholars typically refer to them as chalk giants. Australia's Gummingurru arrangement is a series of additive rock alignments which include emu and turtle and snake effigies as well as some geometric shapes.

    If you broaden the definition a tad, some mounds and mound groups could be included, like the Woodland period Effigy Mounds in the upper midwest and Great Serpent Mound in Ohio: these are low structures made in the shapes of animals or geometric designs. Poverty Point is a settlement in Louisiana that is in the shape of spoked concentric circles. In South America's Amazon rainforest there are hundreds of geometrically-shaped (circles, ellipses, rectangles, and squares) ditched enclosures with flat centers that researchers have termed 'geoglyphs', although they may have served as water reservoirs or community central places.

    So, feeling free to define it on the basis of my reading, I'll define geoglyph as a "human-made rearrangement of the natural landscape to create a geometric form". 

    Desert-Based Geoglyphs

    The most common form of geoglyph—ground drawings—are in fact found in almost all of known deserts of the world.

    Some are figural; many are geometric. Here are a few recently studied examples of the millions recorded throughout the world:

    • Hundreds of thousands of geoglyphs are known in or close to lava fields throughout the Arabian peninsula, named by the Bedouin tribes who live in the Black Desert of Jordan Works of the Old Men. (The Works of the Old Men also included ruins and inscriptions). First brought to scholarly attention by RAF pilots flying over the desert shortly after the Arab revolt of 1916, the geoglyphs were made of stacks of basalt, between two to three slabs high. They are classified into four main categories based on their shape: kites, meandering walls, wheels, and pendants. The kites and associated walls (called desert kites) are thought to be mass kill hunting tools; wheels (circular stone arrangements with spokes) appear to be construction for funerary or ritual use, and pendants are strings of burial cairns. Optically Stimulated Luminescence (OSL dating) on examples in the Wadi Wisad region suggest they were built in two main pulses, one in the Late Neolithic about 8,500 years ago and one about 5,400 years ago during the Early Bronze Age-Chalcolithic. See Athanassas and colleagues below for details.
    • The Geoglyphs of Turgai in the Eurasian steppe of northern Kazakhstan are dated to the early Iron Age (ca 800 BC). There are about ~60 found to date, most of them located on geological points of high relief. They vary in size from 90-436 meters (300-1,400 feet) in length, and shapes include squares with diagonal lines, crosses, circles, or simple rows or lines. One known as the Turgai swastika is a three-rayed triskelion, built of earth ramparts about 30 centimeters (1 foot) high. See Motuzaite Matuzeviciute and colleagues.
    • The famous Nasca lines were created on the coastal desert of Peru between 100 BC-AD 700 by removing the upper level of dark stones making up the desert pavement to reveal the brighter sandy layer below. There are more than 1,500 examples, attributed to water and irrigation, walking, ceremonial activity, ritual clearing, concepts of radiality like those expressed in later Inca ceque system, and perhaps astronomy. Recently Ruggles and Saunders looked at Nasca's LC51 Labyrinth, an asymmetrical group of straight lines which double back on each other. They believe it is a single pathway leading to and from a center, constantly disorienting the walker as s/he goes along the way: to get to the center 60 meters (200 feet) from the exterior, you must walk a distance of 4.4 kilometers (2.7 miles).
    • The Atacama Geoglyphs are located in the coastal desert of Chile. There were more than 5,000 geoglyphs built between 600-1500 AD, made by moving around the dark desert pavement. In addition to figural art including llamas, lizards, dolphins, monkeys, humans, eagles, and rheas, the Atacama glyphs include circles, concentric circles, circles with dots, rectangles, diamonds, arrows, and crosses. One functional purpose suggested by researcher Luis Briones is that of identifying safe passage and water resources through the desert: the Atacama geoglyphs include several examples of drawings of llama caravans.

    Studying, Recording, Dating, and Protecting Geoglyphs

    The documentation of geoglyphs is performed by an ever-increasing variety of remote-sensing techniques including aerial photogrammetry, contemporary high-resolution satellite imagery, radar imagery including Doppler mapping, data from historic CORONA missions, and historic aerial photography such as that of the RAF pilots mapping desert kites.

    Most recently geoglyph researchers use unmanned aerial vehicles (UAVs or drones). Results from all of these techniques need to be verified by pedestrian survey and/or limited excavations.

    Dating geoglyphs is a little tricky, but scholars have used associated pottery or other artifacts, associated structures and historic records, radiocarbon dates taken on charcoal from interior soil sampling, pedological studies of soil formation, and OSL of the soils.

    Sources and Further Information