~1500 YEARS OF HUMAN-LANDSCAPE INTERACTIONS AT EL CHARQUITO, LOWER RIO VERDE VALLEY, OAXACA

The Lower Río Verde Valley (LRVV) located on the Pacific coast of Oaxaca, Mexico has a long history of occupation. The rich archaeological record provides insights into regional occupation and abandonment of sites within the valley. Extensive excavation and regional archaeological survey work indicates that the valley’s population increased throughout the Formative period (4120-1620 cal B.P.) culminating during the Terminal Formative (2065-1620 cal B.P.) with the development of an urban center at Río Viejo (RV) located on the western side of the river. During the Early Classic (1620-1330 cal B.P.) RV declined in size from 200 to 75 ha as occupation switched to the western piedmont. RV saw a renaissance during the Late Classic (1330-1060 cal B.P.) growing to 250 ha but declined again and was abandoned during the Postclassic (1150-428 cal B.P.) when occupation refocused across the river into the eastern piedmont. With such a dynamic cultural and socio-political history the prehistoric population of the LRVV must have had significant and changing impact on their environment. The archaeological data however, offers only basic insights into landscape use for agriculture. To understand variations in spatial and temporal extent of landuse the Río Verde Early Landscape Project (project RVEAL) was established. This project is developing a high temporal resolution data set of paleoecological data (e.g. macrocharcoal, carbon isotopes, and magnetic susceptibility) from 10 sites located throughout the floodplain and coastal region in order to reconstruct landscape change

Earlier reconstructions have primarily focused on the western floodplain and southern coastal region. In this paper we present a ~1500 year high-resolution paleoenvironmental reconstruction from a freshwater lake, El Charquito (0.2 km²). El Charquito is located approximately 10 km north of RV. Initial carbon isotopic signatures and macroscopic charcoal records indicate sustained agricultural activity during the Late Classic coincident with a significant episode of soil erosion. This record will provide critical details, at significant socio-political junctures, regarding anthropogenic landscape interactions which will facilitate a more complete model of the history of human-environment interactions throughout the valley.