Maize important diet food in ancient Peruvian civilisation

Scientists have discovered that during the Late Archaic period between 3000 to 1800 BC, maize or corn was a primary component in the diet of people living in the Norte Chico region of Peru in South America.
Up until now, the prevailing theory was that marine resources, not agriculture and corn, provided the economic engine behind the development of civilisation in the Andean region of Peru.
Researchers led by Field Museum curator Dr Jonathan Haas looked at microscopic evidence found in soil, on stone tools, and in coprolites from ancient sites and dated with over 200 Carbon-14 dates.
After years of study, Haas and his colleagues have concluded that during the Late Archaic, maize 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 3rd millennium BC.

"This new body of evidence demonstrates quite clearly that the very earliest emergence of civilisation in South America was indeed based on agriculture as in the other great civilisations of Mesopotamia, Egypt, India, and China," said Haas in a statement.
Researchers focused on sites in the desert valleys of Pativilca and Fortaleza north of Lima where broad botanical evidence pointed to the extensive production, processing and consumption of maize between 3000 and 1800 BC. They studied a total of 13 sites.

A total of 212 radiocarbon dates were obtained in the course of all the excavations. The team found an abundance of microscopic evidence of maize in various forms in the excavations.

Researchers also analysed 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 analysed, 11 had maize starch grains on the working surfaces and two had maize phytoliths.
Coprolites (preserved fecal material) provide the best direct evidence of prehistoric diet. Among 62 coprolites analysed of all types - 34 human, 16 domesticated dog, and others from various animals - 43 (or 69 per cent) contained maize starch grains, phytoliths, or other remains.
Of the 34 human coprolites, 23 (or 68 per cent) contained evidence of maize. The second most common grain in humans came from sweet potatoes. Coprolites also showed that fish, mostly anchovies, did provide the primary protein in the diet, but not the calories.

Researchers concluded that 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 local diet, and it was not used just on ceremonial occasions.
The study was published in journal Proceedings of the National Academy of Sciences (PNAS).