Evidence For Post-Hispanic Environmental Change In Guerrero, Mexico From High-Resolution Lacustrine Sediment Cores

Abstract

The cumulative impact of the Spanish Contact (c. 1520CE) and the Little Ice Age (c. 1300-1850CE) for environmental change in Mexico is still much debated. We present a subdecadal resolution paleoecological record of environmental change for Laguna Ojo de Mar (LOM), a ~4 ha lake in eastern Guerrero, Mexico. Two sediment cores (2m and 2.9m) were collected from LOM, and AMS radiocarbon dating indicates the basal sediments were deposited approximately c. 1490CE ± 117 (1 SD). Reconstruction of environmental history is based on geochemical data including high-resolution magnetic susceptibility, carbon isotopes, carbon/nitrogen ratio, and loss-on-ignition analysis. Macroscopic charcoal and seed data are used to reconstruct paleoecology and anthropogenic impacts. The combined multi-proxy data suggest low agriculture intensity post-contact through the early 18th century and drought conditions resulting in declining lake levels from the mid-18th century to early 19th century.