PALEOCLIMATE APPLICATIONS TO AN ARCHAEOLOGICAL SITE IN SOUTHERN PERU

In this project, we sought to complement an archaeological project’s perspective on the age and environmental history of an abandoned Spanish-conquest-era village using sediment core data at the site and lichenometry of rhizocarpon geographicum both at the site and at glacial moraines on nearby Mt. Ampato. The village, Mawchu Llacta, was built beginning in the 1570s in the Colca Canyon of Peru and abandoned sometime in the 1800s. It is located at an elevation of 4100 meters and currently has a monsoonal climate with very wet and very dry seasons. The lichenometry at the site allows the archaeological team to date buildings in order to establish when the buildings were constructed and then when they were abandoned. This will allow us to create a theory of the manner in which the Spanish-era site was built on top of a pre-existing Incan village and how it was ultimately abandoned. In a previous expedition to the area, a growth curve for rhizocarpon geographicum at the necessary altitude and climate distribution was established, allowing a growth rate of about 1 centimeter per century to be used in analyzing these data sets. Initial analysis of lichenometry data taken at the glacial moraines of Mt. Ampato suggest that the glacier reached a local maximum about the time the site was established and was in retreat at the time that the archaeological site was abandoned, but the exact climatic conditions that led to this retreat are not known yet. Sediment cores were taken in long-standing irrigation ponds near the site, and we will analyze them for grain size, charcoal, and pollen content that would indicate any notable environmental change at the time that the site was occupied. The climate information gained from these sources will be used to examine the factors that led to the abandonment of this site.