ABSTRACT
This chapter investigates phenomena of a type for particular case where the formation of beach ridges from flood soil/slurry sediment deposition occurs as result of interaction with ocean currents. Many sites within the Supe Valley, with its ceremonial center at Caral, were based upon trade of marine resources from coastal sites exchanged with agricultural products from valley interior sites. The Late Archaic Period of north central coast Peru witnessed increased El Nino ENSO events that transferred flood sediments from coastal valleys into ocean currents forming extensive beach ridges. The chapter focuses on the underlying fluid dynamics of beach ridge formation and the consequences of the induced geomorphic changes by flood and aeolian sand transfer events that affected the agricultural and marine resource base of Late Archaic Period sites. A number of sites at margins of the North Central Coast originated toward the end of Late Archaic Period and survived hundreds of years well into the Formative/Initial Period as preceramic sites.
