February 26, 2013
Coastal Peruvian Civilization Thrived On Maize 5000 Years Ago
April Flowers for redOrbit.com - Your Universe Online
For decades, the emergence of a distinct South American civilization during the Late Archaic period (3000-1800 BC) in Peru has puzzled archaeologists and eluded their understanding. The role of agriculture and particularly corn, or maize, in the evolution of complex, centralized societies has been one of the most persistent questions. The prevailing theory, until now, has been that marine resources provided the economic engine behind the development of civilization in the Andean region of Peru, not agriculture and corn.
A new study led by Field Museum curator Dr. Jonathan Haas is helping to resolve the debate by using carbon-14 dating techniques to examine microscopic evidence in the soil, on stone tools, and in coprolites — preserved fecal matter — from ancient Peruvian sites. The findings of the study were published online in Proceedings of the National Academy of Sciences early edition.
After years of study, Haas´ team now believes during the Late Archaic, maize (Zea mays, or corn) was indeed a primary component in the diets of people living in the Norte Chico region of Peru, a region known for its advanced and flourishing culture around the third millennium BC.
"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," Haas explained.
Haas and his colleagues, which include researchers from the Universidad Peruana Cayetano Heredia, the National Park Service, and University of Nebraska, focused on sites in the desert valleys of Pativilca and Fortaleza, north of Lima, Peru. A variety of botanical evidence at these sites clearly indicates there was extensive production, processing and consumption of maize between 3000 and 1800 BC.
The team studied a total of 13 sites, with the two most extensively studied being located at Cabellete, located about six miles inland from the Pacific Ocean, and Huaricanga, about 14 miles inland. Cabellete consists of six large platform mounds arranged in a "U" shape, while Huaricanga has one very large mound and several much smaller mounds on each side.
At each site, the team targeted specific areas, including residences, trash pits, ceremonial rooms, and campsites. They analyzed a total of 212 samples from the different sites using radiocarbon dating and found macroscopic maize remains — kernels, leaves, stalks and cobs — were rare, while microscopic evidence was relatively abundant in various forms in the excavations.
Large quantities of maize pollen in the prehistoric soil samples was one of the clearest remnants they discovered of the region´s agricultural past. The team was able to rule out modern day contamination since modern pollen grains are much larger and turn a dark red when a stain is applied in the lab. Moreover, modern soil samples contain pollen from the Australian Pine (Casuarinaceae“¯casuarina), which is an invasive species that is new to the area and not found in prehistoric samples.
Most of the 126 soil samples were collected from trash pits associated with residential architecture while others were taken from such places as room floors and construction debris. Of the 126 soil samples analyzed that did not include stone tools and coprolites, 61 contained significant traces of Zea mays pollen. Falling only behind cattails — which have wind-pollinated flowers — in their abundance, Z. mays was the second most common type of pollen found in the samples. This ratio is consistent with findings of maize pollen found in analyses from other sites in various parts of the world where maize is or was a major crop and constitutes the primary source of calories in the diet.
Stone tools used for cutting, scraping, pounding and grinding were also analyzed for plant residues, particularly for starch grains and silica plant remains known as phytoliths. The team also examined fourteen tools and found 11 contained traces of corn starch grains while two had contained maize phytoliths remnants.
The best direct evidence of prehistoric diet of the region´s inhabitants was provided by coprolites. The team analyzed 62 coprolite samples — 34 human, 16 domesticated dog and 12 from various other domesticated animals. Some 69 percent of the samples contained maize starch grains, phytoliths or other corn remains, while 68 percent of the human coprolite samples contained traces of maize. According to coprolite analysis, the second most abundant food source for these ancient peoples appeared to be sweet potatoes, while fish (mostly anchovies) supplied most of the protein in their diet.
Finding maize in multiple contexts and in multiple sites led the researchers to conclude this domesticated food crop was grown widely in the area, that it constituted a major portion of the local inhabitants´ diet, and was not merely used for ceremonial occasions as some researchers have suspected. In the bigger picture, this study once again confirms the importance of agriculture in providing a strong economic base for the rise of complex, centralized societies and civilizations.