By collecting soil samples from excavation sites, researchers
discovered each ushnu had been filled in with earth in one of two
- 1 or Extra-large image
- 2 or Extra-large image
- 3 or Extra-large image
- 4 or Extra-large image
- 5 or Extra-large image
Either rich topsoil and iron-depleted subsoil had been used in layers to fill in the structure. In some, the same contrasting effect was achieved by using alternating layers of coarse and thin soil. Other ushnus, such as Condormarca, had been filled in with soil from outside the local area.
Researchers believe this soil was transported great distances to the ushnus and was perhaps taken from agricultural land.
Researchers also believe that this ritual has great symbolic importance, representing a link between the need for agricultural sustainability and an appeasement of ancestors and deities.
What is geoarchaeology?
The field of geoarchaeology uses a mixture of techniques to study the natural physical processes that affect archaeological sites, the formation of sites through geological processes and the effects on buried sites and artefacts post-deposition. Geoarchaeologists' work frequently involves studying soil and sediments as well as other geographical concepts to contribute an archaeological study. It uses geology, geography, mapping, Geographic Information System (GIS) and Digital Elevation Models.