Archaeology of the Americas

The Pre-Columbian era is the term generally used to encompass all period subdivisions in the history of the Americas spanning the time from the original settlement of the Americas in the Upper Paleolithic up until the European colonization of the Americas during the early modern period. While technically referring to the era before the voyages of Christopher Columbus from 1492 to 1504, in practice the term usually includes the history of American indigenous cultures until they were conquered or significantly influenced by Europeans, even if this happened decades or even centuries after Columbus' initial landing.

The pre-Columbian archaeological record in the Americas is conventionally divided into five large phases according to an enduring system established in Gordon Willey and Philip Phillips's 1958 book Method and Theory in American Archaeology.[1] This differs from old world prehistory where the three-age system, with the Stone Age divided into Paleolithic, Mesolithic, Neolithic, and, Chalcolithic, followed by the Bronze Age and Iron Age, remain in general use.

Folsom projectile point.
National Park Service, c.1961

Numerous regional and sub-regional divisions have since been defined to distinguish various cultures through time and space, as later archaeologists recognized that these generalised stages did not adequately correspond to the cultural variation that existed in different locations in the Americas.[1]

• Lithic stage

Defined by the ostensible prevalence of big-game hunting. In most places, this can be dated to before 8000 BCE, starting most probably around 16,500 BCE (see Paleo-Indians). Examples include the Clovis culture and Folsom tradition groups.

• The Archaic stage

Defined by the increasingly intensive gathering of wild resources with the decline of the big-game hunting lifestyle. Typically, Archaic cultures can be dated from 8000 to 1000 BCE. Examples include the Archaic Southwest, the Arctic small tool tradition, the Poverty Point culture, and the Chan-Chan culture in southern Chile.

• The Formative stage

Defined as "village agriculture" based. Most of these can be dated from 1000 BCE to 500 CE. Examples include the Dorset culture, Zapotec civilization, Mimbres culture, Olmec, Woodland, and Mississippian cultures.

• The Classic stage

Defined as "early civilizations", and typically dating from 500 to 1200 CE. Willey and Phillips considered only cultures from Mesoamerica and Peru to have achieved this level of complexity. Examples include the early Maya and the Toltec.

• The Post-Classic stage

Defined as "later prehispanic civilizations" and typically dated from 1200 CE until the advent of European colonisation. The late Maya and the Aztec cultures were Post-Classic.

Today, for Meso- and Andean South America, the later periods are more often classified using the "Horizon" terminology, with "Early Horizon" typically broadly equating to the Late Formative stage. "Horizons" are periods of cultural stability and political unity, with "Intermediate periods" covering the politically fragmented transition between them. In the Andes, there are three Horizon periods, with two Intermediate periods between them. The Horizons, and their dominant cultures are: Early Horizon, Chavin; Middle Horizon, Tiwanaku and Wari culture; Late Horizon, Inca.[2]

A genetic tree of 18 world human groups by a neighbour-joining autosomal relationships.

Molecular genetics study suggests that surviving Amerindian populations derived from a theoretical single founding population, possibly from only 50 to 70 genetic contributors[7] Preliminary research, restricted to only 9 genomic regions (or loci) have shown a genetic link between original Americas and Asia populations. The study does not address the question of separate migrations for these groups, and excludes other DNA data-sets.[8]

The American Journal of Human Genetics released an article in 2007 stating "Here we show, by using 86 complete mitochondrial genomes, that all Indigenous American haplogroups, including Haplogroup X (mtDNA), were part of a single founding population."[9] Amerindian groups in the Bering Strait region exhibit perhaps the strongest DNA or mitochondrial DNA relations to Siberian peoples. The genetic diversity of Amerindian indigenous groups increase with distance from the assumed entry point into the Americas.[10][11] Certain genetic diversity patterns from West to East suggest at least some coastal migration events.[12] Geneticists have variously estimated that peoples of Asia and the Americas were part of the same population from 42,000 to 21,000 years ago.[13]