Geometric Earthworks in the State of Acre, Brazil: Excavations at the Fazenda Atlântica and Quinauá Sites

Abstract

AbstractGeometric earthworks located in the interfluvial zone of the Upper Purús and Madeira river tributaries in the southwestern Amazon are formed by ditches of varying shapes and sizes along with contiguous exterior embankments and roads terraced with low backfill banks. The earthworks in the Brazilian state of Acre were used from 1200 B.C. to the fourteenth century A.D., indicating a continuous, collective cultural institution, a generalized regional phenomenon characterized by local variants and alterations and probably not exclusively restricted to a specified ethnic group. The carefully planned position of the earthworks in the landscape and the recurring geometric forms represented in this earthwork architecture suggest functions that were part of a tradition of shared ideology related to rituals and/or the sociopolitical activities of ancient Amazonian peoples. Recent archaeological fieldwork on two composite earthwork sites, Fazenda Atlântica and Quinauá, situated in the core location of the geometric earthworks, provides further evidence for the predominantly ceremonial use of these constructions.