Cultural landscape and stratigraphical evidence of the anthropocene in the Mixteca Alta region, Oaxaca

The proposed Anthropocene epoch related to the control of geosistems by human activity is analyzed on the basis of environmental vs. anthropical conditions of soil development on agricultural terraces (known locally as lamabordos) at Mixteca Alta, Oaxaca, Mexico. The complex relationships between landscape development, changes in environmental conditions, and culturally-driven transformations constitute spatial and temporal indicators of landscape transformation at a regional level. These indicators formed of old soils easily recognizable and differentiated by their morphology, color, stratigraphic position, and age, are a result of cultural transformations controlled by human activities, linked to the use of resources, the land usage, demography and land use planning of their settlement. The older soils, chromic Cambisols (calcaric), were formed during late Pleistocene. During early Holocene an increase of erosional processes allow a poor soil development (calcic Fluvisol). The soils developed 7900 years BP show evidence of anthropic impact (e.g. concentration of carbon particles). Towards middle Holocene (approximately 5500 years BP), the landscape was thoroughly transformed as a consequence of lamabordos building and an increase of the agricultural activity; soils developed are easily recognized in the field and can be regarded as stratigraphic markers. Here we suggest that these soils allow us to link to a new epoch in the Mixteca defined as the Anthropocene. Soils of late Holocene, developed between 2000 and 500 years BP, contain a higher content of carbon fragments and evidence of an increase in the phases of alluvial accumulation, suggesting a more intensive cultural use by settlement groups of the region.