Overlooked for at least a century because there was no pottery or gold, a sand-swept region of archaeological sites in north-central Peru is now believed to be the place where cultural evolution in the Andes — and in the Americas, for that matter — first diverged from simple hunting and gathering into complex society. Recent archaeological excavations bring into focus a civilization that acrose more than 5,000 years ago in three small valleys 100 miles north of Lima. Over more than a millennium, it spurred the development of more than 20 separate major residential centers. They are characterized by monumental architecture, large circular ceremonial structures, irrigated agriculture and housing.
Researchers publishing in the Dec. 23 edition of the scientific journal Nature used radiocarbon dating to determine the rise and fall of this first complex society of the Americas, from roughly 3000 to 1800 B.C., and document the extent of its influence, which covered an area of nearly 700 square miles (1,800 square kilometers) throughout Peru’s dry and dune-covered Norte Chico region. Monumental architecture was evident at each site in the presence of large platform mounds, also described as rectangular terraced pyramids, which reached as high as 85 feet (26 meters).
“This wasn’t a single site where people were doing something really unusual, but a whole region, a whole culture, where people were organized to produce large pyramids and sunken plazas—something the Americas hadn’t seen before,” said Professor Winifred Creamer, a Northern Illinois University anthropologist. “The people who built the first of these structures had no model to go by, no precedent to use in building a monument. It’s a bit like deciding to build a functioning spaceship in your back yard, and succeeding.”
Creamer is a co-author of the Nature article with her husband Jonathan Haas of The Field Museum in Chicago and with NIU graduate student Alvaro Ruiz, the Peruvian co-director of the project. In 2001, Creamer and Haas were part of the research team announcing that six immense platform mounds at the site of Caral in the Andes’ Supe Valley represented the oldest known man-made monuments in the Americas.
The latest findings demonstrate that sites such as Caral were part of a much larger complex of residential centers in a region that includes the Supe, Pativilca and Fortaleza river valleys. The researchers present 95 new radiocarbon dates from test excavation samples at 13 of more than 20 inland archeological sites in Norte Chico, a region that stretches from the Andes to the western coastline of central Peru. Added to previously published dates from earlier research, 127 radiocarbon dates are now available from the region, firmly establishing a civilization thriving in the Norte Chico for more than 1,200 years.
“The scale and sophistication of these sites is unheard of anywhere in the New World at this time, and almost any time,” said NIU Adjunct Professor Haas, who is MacArthur Curator of Anthropology at The Field Museum. “The cultural pattern that emerged in this small area in the third millennium B.C. later established a foundation for 4,000 years of cultural florescence in other parts of the Andes.”
The researchers’ findings also challenge the theory that the initial emergence of complex society in the Andes was based on the exploitation of maritime resources rather than agriculture.
“In Norte Chico, the path of cultural evolution in the Andean region diverged from a relatively simple hunting and gathering society to a much more complex pattern of social and political organization, with a mixed economy based on agriculture and marine exploitation,” NIU’s Ruiz said. “With this new information, we need to rethink our ideas about the economic, social and cultural development of the beginnings of civilization in Peru and all of South America.”
The dates show the clear appearance of large-scale communal construction between 3200 and 2500 B.C., corresponding with previously collected construction dates at Aspero, a coastal fishing community with evidence of similar ancient architecture. The researchers did not find an obvious center or starting point for the ancient culture. The next 500 years, however, marked a period of expanded occupation and construction in Norte Chico’s inland sites, which were consistently located adjacent to short irrigation canals watering large tracts of land.
The 13 inland centers studied range in area from 25 to more than 250 acres (10 to more than 100 hectares). Each has between one and seven rectangular terraced pyramids. The largest of these mounds range from 105,000 to more than 196,000 cubic yards (80,000 to more than 150,000 cubic meters) in volume. Rooms were constructed on the tops and upper terraces of the structures. Another hallmark of the sites is the presence of sunken circular plazas, ranging from 22 yards to 44 yards (20 to 40 meters) in diameter and 1 to 2 yards deep.
Radiocarbon dating was performed on the remains of annual plants, including reeds and wild cane, which were woven into mesh bags and used to tote rocks to construction sites. “The inhabitants of Norte Chico seemed to have put all their energy into construction of these massive structures, and they were very frequently remodeling,” Creamer said. “In cases where we have been able to examine the interior of the mounds, we see what appear to be many different periods of construction. You can see the walls and floors and processes of construction and remodeling.”
Together, the Norte Chico sites indicate an advanced civilization that arose without the development of ceramics—a hallmark of other complex societies worldwide. Yet the researchers found indications of a multifaceted economy based on inland irrigation of cotton and food plants, diverse marine resources and a system of regular exchange between inland and coastal sites. Numerous remains of shellfish and fish bones were recovered at the inland sites.
Researchers also recovered botanical remains of domesticated plants—including cotton, squash, chilli, beans and avocadoes—but found almost no evidence of preserved corn or other grains. “This early culture appears to have developed not only without pottery, arts and crafts but also without a staple grain-based food, which is usually the first large-scale agricultural product of complex societies,” Creamer said. “The ancient Peruvians took a different path to civilization.”
More excavation will be required to estimate the population of the residential centers. The sites have large expanses with features indicating residential architecture, and the team found the remains of dwellings, some made of adobe and others of wood poles, cane and mud. “There hasn’t been enough excavation to show if the ancient inhabitants of Norte Chico had things like workshops and marketplaces, and we don’t know for sure whether they lived here year-round or came here only on specific occasions,” Creamer said.
The researchers also want to learn more about why a complex society evolved in the arid, harsh environment of Norte Chico, which today is sparsely populated. “Why did this happen here of all places?” Creamer said. “It’s not a particularly easy environment, but the big moment may have been when someone discovered that irrigation wasn’t that difficult.
“You can use irrigation to explain both the rise and fall of the Norte Chico region,” she added. “By 1800 B.C., when this civilization is in decline, we begin to find extensive canals farther north. People were moving to more fertile ground and taking their knowledge of irrigation with them. The Norte Chico ultimately became something of a frontier zone between northern and southern centers of influence and political development.”