Most of the Peruvian coast is geologically homogenious: alluvial terraces with gentle slopes run from the Andean foothills to the ocean. These great terraces are transversely cut by the river basins, which carry water from the Andean glaciers to the ocean.
The Pampas of Jumana converge exactly into one of the great alluvial formations, where the mountain streams have a very short course, so they are not provided with enough water to cover the surface. This fact and the great lack of local rains - one of the lowest rainfalls in the world - characterise the arid landscape of the region.
Most of the vast pampas' surface is covered by pebbles. Their color has become reddish ochre because of long exposure to wind and weather.
The ancient dwellers noticed that the light alluvial surface of the pebbles was exposed by superficially sweeping them. Most of the great desings were made using this technic. The lines were drawn on the field by sweeping along the surface with variable widths. The figures were formed by a contrasting effect.
This technique was used in large areas to form trapezoidal figures of immense proportions, along with another technique used by the ancient dwellers. This consisted in the gathering of stones and pebbles which made patterns in relief. Equally, by removing the stones the contrast formed the figures.
CONSERVATION
The same geological features that made it easier for the ancient dwellers to draw these great desings on the pampas threatened their conservation in a direct way. Cars, motorcycles, bicycles and even walking through the area leave tracks, which remain eternally imprinted on the arid surface. After moving away, removing or dispersing the thin layer of reddish stones, the white-yellowish layer underneath is exposed and a print is made. These prints can be noted by looking carefully at the aereal pictures of the geoglyphes, many of which are partially deformed.
The building of the Panamericana Sur Highway and of some local roads have caused the destruction of some sections and figures, but most of them are in optimal condition.