Late Pleistocene-Holocene paleoclimatic implications in the Mixteca Alta, Oaxaca, Mexico, by using rock magnetism and micromorphological techniques

Abstract

Paleosols and sediments in the Yanhuitlán Basin were analyzed to reconstruct the environmental conditions and human-environmental interactions for generating a terminal Pleistocene-Holocene paleoclimate record in the south of Mexico. Magnetic concentration, mineralogy and grain size domains were compared with micromorphological studies to infer variations in the transportation of clastic minerals, oxide and redox conditions in the materials and anthropogenic activities. In general, conditions for the terminal Pleistocene (?–11,700 BP) were humid and transitional until the establishment of drier conditions at the end of the Pleistocene. For the early Holocene (11,700–8200 BP), the conditions were wetter and controlled by seasonal precipitation; in the middle Holocene (8200–4200 BP), the climate indicated drier conditions. Finally, in the late Holocene (4200–0 BP), the climate suggests more humid conditions but oscillating to dry stages accompanied by anthropogenic activities, manifested by an increase in sedimentation rates at the end of the period, charcoal oscillations and poor soil development.