Umberto Lombardo from the University of Bern in Switzerland and an international group of colleagues from other institutions reported the discovery of the first hard evidence that man was living in and active in the Amazonian areas of Bolivia as early as 10,400 years ago in the Aug. 28, 2013, issue of the journal Public Library of Science.
The scientists investigated three of the hundreds of waste dump islands called middens found in the Bolivian Amazon. The mounds were previously attributed to termite activity, erosion, or possibly early human activity but not as far back in time as carbon dating has determined.
A layer by layer examination of three of the middens using core sampling produced evidence of human activity and habitation as far back as 10,400 years ago.
The mounds showed evidence of humans from layers of charcoal from burning, fresh water snail shells, and human bones. The oldest layer contained only snail shells. The upper layers contained pottery fragments, human bones, and bone tools.
This is the first known evidence that hunter-gatherers lived in this area of the Amazon in Bolivia during the Holocene. The mounds offer evidence that humans lived and apparently thrived in the region for over 6,000 years.
The mounds were abandoned as early men moved in reaction to an increasingly wetter climate in the area.
These are the oldest human artifacts found in n western and southern Amazonia.