Stable isotope evidence of diet at Las Orquídeas (800 – 200 cal BCE): A Late Formative site in the highlands of Ecuador

In Ecuador, the Formative period (3800 – 300 cal BCE) has long been characterized by the presence of sedentary human settlements and the increased importance of agriculture. For the northern highlands, our knowledge of this period has been based primarily on two sites: Cotocollao and La Chimba. In the last decade, research at the site of Las Orquídeas (San Antonio de Ibarra, Imbabura province) is producing new data for this period. To reconstruct diet at Las Orquídeas, eight human and 13 faunal bone samples were analyzed using carbon and nitrogen stable isotope analysis of bone collagen. The results show that the site's inhabitants consumed a mix of C₃ and C₄ resources, along with protein from a number of faunal taxa. Two cervids exhibit isotopic signals that suggest they consumed maize near the settlement. Additionally, the δ¹³C and δ¹⁵N values of the two latest human individuals suggest that diet may have became more variable after 400 cal BCE; this, along with the grave goods interred with one individual, may reflect increased social inequality.