Late Holocene climate and environmental change in the Teuchitlán basin, Jalisco, Mexico

A 116 cm sediment sequence from paleolake Teuchitlan provided information for the last 4000 years related to past climate and human disturbance in western Mesoamerica. Concentrations of Ti, Zr, CaCO 3 , and TOC were compared with their average values to infer variations in runoff, perturbation of sediments, lakewater salinity and productivity in the basin. During the first half of the Late Holocene (∼4.0–1.9 ka), conditions were generally dry. Highest abundance of CaCO 3 occurred at 3.95–3.90, 3.85–3.55, and 3.35–3.05 ka, and below-average transport of Ti-bearing clastic minerals during 2.75–2.15 ka indicates arid conditions within this generally drier interval of the Late Holocene. Southward migration of the Inter-Tropical Convergence Zone, summer insolation and increased ENSO activity influenced summer precipitation and overall hydrologic variations during this interval. During the time period 1.9–0.3 ka (100–1600 CE), Ti, Zr and K indicate a mixed source, from the Early Classic (100 CE) until the end of the Postclassic (1600 CE), during a period of increasingly moist conditions. Enhanced evidence of human activities is related to agricultural practices during the Classic, Epiclassic and Postclassic Periods, associated with greater transport of allochthonous sediments from both nearby and distant sources. The Colonial-Industrial Period (1600–2017 CE) was characterized by an increase in human activities, with periodic additions of materials for agriculture in the region.