February 14, 2009 Clark Erickson, PhD, University of Pennsylvania: "Pre-Columbian Monumental Earthworks of the Amazon"

            Traditionally, archaeologists have believed the vast Amazon region of South America to be a cultural backwater compared to the better-known civilizations that developed in the Americas. Scholars stress the limitations of tropical environments and lack of critical technological innovations to sustain large dense populations, intensive agriculture, monumental architecture, urban centers, and complex forms of society: the foundations of any civilization and complex societies. In recent years, the documentation of raised field agriculture, anthropogenic, or human created, black earth, managed forests, hydraulic engineering, and dense large settlements for several regions of the Amazon has questioned traditional assumptions about lack of cultural development. The anthropogenic black earth, which contained organic refuse, charcoal and potsherds is a particularly vital  feature of the Amazon region. Its layers can be up to 3 meters deep, and it is regularly mined for use by current farmers.  Much evidence of anthropogenic husbandry can still be found throughout the region:  seen in patches of manioc and sweet potatoes, as well as stands of chocolate and non-native fruit trees.
            In collaboration with a small team of Bolivian archaeologists during 2007 and 2008, Dr. Erickson documented over a hundred examples of a fascinating form of monumental earthworks called ring ditches or geoglyphs, which he described in his talk. Many of these earthworks, as well as accompanying raised fields, canals and roads, could only be identified by aerial photography and satellite imagery. Dr. Erickson actually identified raised fields in the savanna using Google Earth. The ditches and embankments encircle areas of several acres to nearly a square mile. Some earthworks are precisely constructed in geometric patterns, such as circles, ellipses, and squares that suggest a clear concern for landscape design, appearance, and aesthetics. Deep ditches of up to 12 feet deep and 20 feet wide suggest tens of thousands of cubic yards of earth moved during their construction. During the 2008 season, Dr. Erickson and his collaborators hiked into the forest and were able to get usable GPS signals in order to find and study ring ditches previously identified from the air. The group found ditches that would have been up to five meters deep, now eroded. The ditches were probed, but not excavated; often surface pottery was found near the mounds.
            Various hypotheses were presented for the functions of earthworks based on forms and associations. Many of the earthworks show a preponderance of ceremonial ware, as opposed to domestic pottery, and the scale and number of man-hours needed to construct such earthworks points to a greater degree of social organization than previously accepted. The existence of monumental works of such magnitude and density throughout Western Amazonia requires demands a reassessment of the prehistory of the region and the ability of native peoples to transform their landscapes at a massive scal
            Following his studies at Washington University, St. Louis, Missouri, Dr. Erickson received his  M.A. and  Ph.D. in Anthropology from the  University of Illinois, Urbana-Champaign. He is currently an Associate Professor in the Department of Anthropology, at the University of Pennsylvania, and an Associate Curator in the American Section of the University Museum of Archaeology and Anthropology.  He is currently directing a multi-year, multidisciplinary investigation of traditional agricultural systems of agricultural production, precolumbian land use, anthropogenic landscapes, human environmental impact, and the technological and engineering knowledge of prehispanic farmers in the Amazonian region of Bolivia, at  Llanos de Moxos, Department of the Beni, Bolivia. The fieldwork involves archaeological survey, mapping, and excavation of agricultural earthworks, digital analysis of remote sensing, and establishment of a Geographic Information System. The research also includes agricultural experimentation based on the now-abandoned technology defined from archaeological research. During the 1980s, Clark first investigated prehispanic raised field agriculture in the Lake Titicaca Basin of Peru.  Between 1990 and 1994, his group developed an applied archaeology program whereby indigenous communities participated in the raised field experiments. After 1995, they focused their investigations on a vast complex of precolumbian earthworks in the Baures, the region along the border between Bolivia and Brazil. Their research is funded by the National Science Foundation, H. John Heinz Charitable Trust, the Research Foundation, American Philosophical Society, and the InterAmerican Foundation.
      Dr. Erickson is widely published. Among his most recent  publications are:
2008: Amazonia: The Historical Ecology of a Domesticated Landscape.   The Handbook of South American Archaeology, Edited by Helaine Silverman and William Isbell, Springer, New York.
2006: Time and Complexity in Historical Ecology: Studies in the Neotropical Lowlands. Edited by William Balée and Clark L. Erickson, Columbia University Press, New York.
2006: Intensification, Political Economy, and the Farming Community; In Defense Of A Bottom-Up Perspective Of The Past. in Agricultural Strategies. Edited by Joyce Marcus and Charles Stanish, Cotsen Institute.
2006: The Domesticated Landscapes of the Bolivian Amazon. in Time and Complexity in Historical Ecology: Studies in the Neotropical Lowlands. Edited by William Balée and Clark Erickson, Columbia University Press,
For any who wish to read these and other recent articles Dr. Erickson has published, please go to:
recent press articles about Dr. Erickson, and his research can also be accessed from:  
http://www.sas.upenn.edu/anthro/people/faculty/cerickso , including:
Mann, Charles 2008: Ancient Earthmovers of the Amazon. Science 321:1148-1152. (29 August 2008),
Hvistendah, Mara 2008:  Amazonian Harvest: Can Prehistoric Farming Methods lead us to a Sustainable Future? Archaeology 61(4):20-25. (July/August 2008).

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