NEW GEOARCHEOLOGICAL AND ENVIRONMENTAL INSIGHTS AT THE PRECERAMIC-AGE LOS MORTEROS ARCHAEOLOGICAL SITE, NORTH COAST PERU

Los Morteros, a large mound-shaped feature located on the north coast of Peru, is identified as a prehistoric site on the basis of Preceramic-age midden deposits, exposed human burials, and scattered ground stone mortars that give the site its name. Reconaissance-level ground-penetrating radar (GPR) investigations in 2006, followed by detailed worked in 2010 indicated the presence of “hard” reflectors in the interior of the mound inconsistent with eolian deposition, and established a human origin for the feature. Targeted trench excavations, combined with geological and archaeological surveys of the surrounding area within the past year provide new information that allow “ground-truthing” of the GPR data, and help place the Los Morteros site within an ecological and archaeological context. Structures uncovered by excavations, including stone-paved floors and vertical walls, are linked to reflectors in the GPR data, and are used to locate the presence of other human constructions within the mound. Statigraphic information derived from trench profiles allows identification of specific units within the GPR profiles. Preliminary interpretation of these data suggests a combined eolian and human role in the mound’s formation.

The mound’s enigmatic location in a hyperarid setting on a higher-than-present paleoshoreline, approximately 5 km from the modern Pacific Ocean beach, and 6.5 km from the nearest source of surface water at the Chao River, suggests a significantly different setting in terms of access to marine resources and fresh water at the time of occupation. The new geological and archaeological studies conducted in this area offer some of the first clues to understanding the profound environmental changes in this region.