THE SPATIAL AND TEMPORAL DISTRIBUTION OF METALWORKING WITHIN NORTHERN PERU

Lake sediment archives can be used to document historical metallurgy as well as modern pollution. This project uses trace metal concentrations within lake core sediments to determine the timing, magnitude, and extent of historic and modern metal pollution within lakes in Northern Peru, an understudied region compared to the south and central regions of the country. Specifically, this research aims to correlate Lakes Collazgon and Huaylillas metal concentrations with archaeological and historical information and to test if mining activity and metallurgy activities can be detected. We measured weakly-bound trace metals within the sediment using an inductively coupled plasma-optical emission spectrometer (ICP-OES) and identified lead, copper, silver, tin, aluminum, chromium, iron, manganese, zinc, and antimony as indicators of historic metallurgy. Additionally, we measured mercury concentrations as an indicator of gold processing and amalgamation. To determine timing of metal enrichments in sediments we constructed age models of the lakes using radiocarbon dates and ²¹⁰Pb profiles. Our preliminary results suggest that lake sediment cores are useful in determining trace and heavy metal concentrations deposited from modern human activity within the studied lakes. Though there is evidence of prehispanic metallurgy much earlier, lake records suggest peaks of activity at about 900 – 1000 AD which could be related to gold production. These results demonstrate that sediments are useful in the construction of an anthropological history of metal use within this region, and that metallurgy precedes the colonial era, possibly arising with the advent of the Chimu and/or Moche native peoples.