For years, archaeologists have debated the economic basis for the rise of civilization in the Andean region of Peru. The prevailing theory advanced the notion that the development and consumption of marine resources was the primary mover. Now, however, a team of research scientists have found evidence to dispel that theory.
Led by the Field Museum curator Dr. Jonathan Haas, a team of researchers examined and evaluated ancient microscopic residues of maize in the form of pollen, starch grains and phytoliths (plant silica bodies) found in soil, on stone tools, and in coprolites (preserved fecal matter) from ancient sites, using 212 instances where Carbon-14 dates were obtained. They focused on 13 desert valley sites of Pativilca and Fortaleza, north of Lima, where they found broad botanical evidence that indicated extensive production, processing and consumption of maize between 3000 and 1800 B.C. The two most extensively studied sites were Caballete, about six miles inland from the Pacific Ocean and consisting of six large platform mounds arranged in a “U” shape, and the site of Huaricanga, about 14 miles inland, featuring one large mound and several smaller mounds. They targeted residences, trash pits, ceremonial rooms, and campsites, but most of the samples were taken from trash pits of residences.
Of 126 soil samples analyzed, 61 contained Z. mays pollen, consistent with the percentage of maize pollen found in pollen analyses from sites in other parts of the world where maize is a major crop and constitutes the primary source of calories in the diet.
The researchers also analyzed residues on stone tools used for cutting, scraping, pounding, and grinding. The tools were examined for evidence of plant residues, particularly starch grains and phytoliths (plant silica bodies). Of the 14 stone tools analyzed, 11 had maize starch grains on the working surfaces and two had maize phytoliths.
But coprolites provided the best direct evidence of prehistoric diet. Among 62 coprolites analyzed – 34 human, 16 domesticated dog, and others from various animals – 43 (or 69 percent) contained maize starch grains, phytoliths, or other remains. Of the 34 human coprolites, 23 (or 68 percent) contained evidence of maize. The second most common grain found was sweet potatoes. The coprolites also showed that fish, mostly anchovies, provided the primary protein in the diet, but not the calories.
While maize is grown in the area today, they were able to rule out modern day contamination because modern maize pollen grains are larger and turn dark red when stain is applied. Also, modern soil samples consistently contain pollen from the Australian Pine (Casuarinaceae Casuarina), a plant which is an invasive species from Australia never found in prehistoric samples.
After years of study, Haas and his colleagues have concluded that during the Late Archaic, maize (Zea mays, or corn) was indeed a primary component in the diet of people living in the Norte Chico region of Peru, an area of remarkable cultural florescence in the 3rd millennium B.C. Moreover, the prevalence of maize in multiple contexts and in multiple sites indicates this domesticated food crop was grown widely in the area and constituted a major portion of the ancient inhabitants’ diet, not confined only to ceremonial occasions.
The research results reinforce the importance of agriculture in providing a strong economic base for the rise of complex, centralized societies in the emergence of civilizations. “This new body of evidence demonstrates quite clearly that the very earliest emergence of civilization in South America was indeed based on agriculture as in the other great civilizations of Mesopotamia, Egypt, India, and China,” said Haas.
All of the botanical work conducted on this project was carried out at the new Laboratorio de Palinología y Paleobotánica at the Universidad Peruana Cayetano Heredia, under the direction of Luis Huamán. Analysis of the botanical remains was a collaboration among Huaman, David Goldstein, National Park Service, Karl Reinhard, University of Nebraska, Cindy Vergel, Universidad Peruana Cayetano Heredia. The Project was co-directed by Haas and Winifred Creamer, Northern Illinois University, with funding from the National Science Foundation.
The detailed report appears in the online Early Edition issue of Proceedings of the National Academy of Sciences (PNAS) the week of February 25, 2013.
Feb 25, 2013