Pre-Columbian Earthworks in the Riberalta Region of the Bolivian Amazon

Abstract

Interpretations of the Amazonia prehistory have changed significantly in the last few decades, as the complexity and diversity of the Amazonian cultures are beginning to be documented and understood. Earthworking, a long-term conscious anthropogenic landscape alteration, was a widespread phenomenon throughout the South American tropical lowlands. A variety of earthworks has been documented in the Southwest Amazon, including ditches and embankments of different shapes and sizes, roads, extensive raised fields, canals, causeways, and artificial wetlands linked to adjacent mounds and forest island settlement sites. A field survey and test excavations were undertaken in the region of Riberalta, in the Bolivian Amazon. The purpose of these investigations was to study the distribution and characteristics of the pre-Columbian occupation in the region. We found different types of sites, some without visible earthworks, indicating fairly dense occupation on river bluffs and terra firme, but lacking long permanence in the same location. The earthwork tradition prevailed in the Riberalta region from at least 100 B.C. until the period of European contact. The function of the less-complex earthworks may have been to enclose the occupation areas, and in some cases, to serve as canals. Compared to the variable layout of the sites, the ceramic assemblages of the region are relatively homogeneous. A central objective for future research will be to determine if the earthwork sites correlate with a single or multiple cultural traditions.Key-words: Southwest Amazonian archaeology, earthworks, ceramic traditions.

Eco-archaeological regions in the Bolivian Amazon

“…Ring ditches were mainly built on the relatively old, reddish soils of flood-free areas. Saunaluoma (2010) reports that ring ditches in Pando were occupied and re-occupied for short periods of time from 100 BC to 400 AD and from 1200 AD until the arrival of the Spaniards. The ring ditch of Bella Vista, in the LM, was occupied ca.…”

“…However, no evidence of post holes or other kinds of defensive structures have been found in the ditches or associated berms in the area of Bella Vista (Prümers 2010). Other interpretations of ring ditches, which are not necessarily exclusive, are that they served ceremonial, ritual or monumental functions (Erickson 2010), delimited and marked the area of occupation (Saunaluoma 2010) and/or served as water reservoirs (Pärssinen et al 2003). According to Saunaluoma (2010), the earthworks in the Pando area are less complex and diverse than those found in the central LM and in the State of Acre.…”

“…Other interpretations of ring ditches, which are not necessarily exclusive, are that they served ceremonial, ritual or monumental functions (Erickson 2010), delimited and marked the area of occupation (Saunaluoma 2010) and/or served as water reservoirs (Pärssinen et al 2003). According to Saunaluoma (2010), the earthworks in the Pando area are less complex and diverse than those found in the central LM and in the State of Acre. In any case, it would seem that ring ditches required less labour for their construction than the other types of earthworks found in the LM (Arnold & Prettol 1988).…”

“…This analysis also overlooks the diversity of geo-ecological regions in north-eastern Bolivia, consequently missing potential links which might exist between the different archaeological remains and their environmental settings. Detailed archaeological excavations of pre-Columbian settlements have been carried out only in a limited area of the LM (Prümers 2010;Prümers et al 2005) and Pando (Arnold & Prettol 1988;Saunaluoma 2010). They have provided useful data at a local scale, such as the first pottery seriation for the region of Casarabe (Jaimes Betancourt 2010).…”

Os sítios pré-colombianos com estruturas de terra na região de fronteira entre o Acre, Brasil, e Riberalta, Bolívia, Amazônia sul-ocidental

“…Sítios com estruturas de terra investigados na região de Riberalta exibem mais variação tipológica, mas são estruturalmente menos complexos do que os do Acre (SAUNALUOMA, 2010). O sítio Tumichucua apresenta uma valeta circular com 775 m de diâmetro conectada a um semicírculo adjacente a um lago em ferradura e um canal que liga o lago e a planície de inundação do rio Beni (Figura 2).…”