Draft:Timeline of Indigenous American history

Exploration Period
The period starting with the first arrival of humans into North America (whatever date that may be) and ending with the dawn of the Clovis culture has been termed the Exploration Period, although "Pre-Clovis" is an older term.
 * 30,000 years ago: The latest stable emergence of Beringia, the land bridge uniting Alaska and Chukotka, forms. Crossing from Siberia is considered the primary route of origin for Indigenous American populations for tens of thousands of years. Prior to this date, Beringia was intermittently submerged up to 60,000 years ago, where it was stable again up to 70,000 years ago. However, Homo sapiens did not begin to successfully establish themselves outside Africa until approximately 70,000 — 50,000 years ago, and the earliest evidence of humans in eastern Siberia is in the Yana Rhinoceros Horn Site 32,000 — 27,000 years ago. Therefore, it is not thought that Homo sapiens or any other hominin migrated into Beringia significantly earlier than 30,000 years ago.


 * 30,000 — 20,000 years ago: The ancestors of American Indians and Indigenous peoples of Siberia are calculated to diverge at this time (that is, substantially measurable levels of gene flow stopped). Beringia may have already been settled during or prior to this period.


 * 25,000 — 20,000 years ago: Ancient North Eurasians migrate into eastern Siberia, intermixing with the local Ancient East Asian populations and helping to form the Ancestral Native Americans. It is not currently known if this took place near Lake Baikal or as potentially far east as western Beringia.
 * 24,000 years ago: Earliest evidence of human habitation in North America: The Bluefish Caves on the western border of Yukon can be dated to this age, signaling the migration of humans across the Bering land bridge.
 * 23,000 — 20,000 years ago: Fossilized footprints at White Sands National Park are the oldest confirmed evidence of human presence in the Americas south of the Laurentide ice sheet. The footprints of ground sloths and Columbian mammoths are also found associated with the human footprints.
 * 20,000 years ago: The Ancient Beringians diverge from the Ancestral Native American lineage. They either left no living descendants or they were heavily absorbed by a back-migration of North Native Americans many thousands of years later.
 * 19,000 years ago: The western section of the Laurentide Ice Sheet begins to deglaciate, separating from the Cordilleran Ice Sheet and slowly creating an ice-free corridor (IFC) over the course of millennia. A northern funnel appears in the Yukon.
 * 17,000 years ago: The coastal margin of the Cordilleran Ice Sheet begins to melt due to warmer ocean currents, deglaciating the Pacific Northwest Coast and much of the Pacific coast of Alaska. Additionaly, there is evidence of a highly productive marine and coastal ecosystem at this time that could have supported populations of migrating humans.


 * 16,000 years ago: Mitochondrial DNA in American Indian genomes record a population expansion at this date. It is thought to be connected to humans migrating south of the Laurentide glacier; as this was well before the corridor had opened up, it likely represents a coastal migration route which also coincides with the decline of the Northwest Coast glaciers a thousand years prior. Similarly, Y-chromosome lines appear to have expanded 15,000 years ago.
 * 15,000 — 14,000 years ago: High and intermediate-elevation sites in the ice-free corridor are free of ice.
 * 14,870 years ago: Deglaciated areas of the IFC show signs of rapid revegetation.
 * 14,775 ± 200 years ago: The date of the Hebior Mammoth, a kill site excavated in Kenosha County, Wisconsin. It is the earliest mammoth kill south of the glaciers to date.
 * 14,550 years ago: The Monte Verde site in southern Chile is dated to this age, with potential for some strata to be even older. It is among the first sites to contradict the then-standard narrative of the Clovis culture being the first to migrate into the Americas, and supports a Pacific coast migration route. Furthermore, the subhaplogroup D1g in native Chilean populations is as old as 25,000 years, providing further evidence for an early and rapid coastal migration.
 * 14,500 years ago: A human coprolite from Paisley Caves, Oregon is dated to this time. Along with a near-contemporaneous modified bulrush shaft, they provide evidence for human occupation before the Clovis expansion as well as evidence for the Western Stemmed tradition existing at the same time as (or predating) the Clovis culture, supporting a hypothesis that stemmed points represent the earliest migrations into the Americas. Although DNA recovered from the coprolites contain the same haplogroups as the founder populations of Native Americans, there is no further detail on the precise relationship with Clovis and no other pre-Clovis sites are currently known to have human remains whose genomes can be salvaged and sequenced.
 * 14,200 years ago: The Swan Point Archaeological Site in eastern Alaska. It was traditionally considered the oldest evidence of human habitation in Alaska, but has been superseded by a few older sites. Nevertheless, sites in and near the ice-free corridor become substantially more documented after this date.
 * 13,800 years ago: The ice-free corridor may have been completely open by this date, based on cosmogenic 10Be dating.

Clovis era

 * 13,400 — 12,900 years ago: Clovis points are invented, possibly somewhere in the southern Great Plains where they may have evolved from an earlier stemmed-point tradition. The large, intricately made, fluted bifacial blades are associated with the dawn of big game hunting (including mammoths and mastodons) in North America. Although they appear to be well-suited for this purpose, the points may have also been multifunctional tools with other cutting uses. The points herald the dawn of the Clovis culture, traditionally considered the oldest archaeological culture — even the oldest people — in temperate America, although this has been significantly contested in recent years.
 * 13,300 years ago: Detectable human presence in the southern funnel of the ice-free corridor: an animal butchering site near St. Mary Reservoir in Alberta.
 * 13,250 — 9,000 years ago: The currently most substantiated timeframe for the Cooper's Ferry site in western Idaho. A more tentative date of up to 16,000 years ago has been proposed as well as potential connections between the Western Stemmed tradition and pre-Jomon cultures of northern Japan, but both counts have been seriously contested by other researchers citing poor confidence of the dating methods and contradictions in the evidence.  Although the original researchers who made these claims no longer believe in a connection to Japan, they continue to trust their re-analyzed dates of ~15,785 years ago.
 * 13,100 years ago: Evidence of horses and camels within the ice-free corridor.
 * 13,000 — 11,500 years ago: The Cordilleran and Laurentide ice sheets melt substantially. Rising sea levels render the Bering land bridge no longer traversable on foot, becoming the modern Bering Strait and cutting off further ground-based migrations. The discharge of freshwater into the ocean is thought to have disrupted ocean currents, becoming a likely trigger for the Younger Dryas cold episode.
 * 12,707 — 12,556 years ago: The age of Anzick-1, an infant from the Clovis culture in Wilsall, Montana. Anzick-1 was the first ancient American genome to be sequenced, and the findings showed that not only were Clovis populations ancestral to modern American Indians but that they were descended from Siberian peoples, with the same evidence of Ancient North Eurasian gene flow as modern Native Americans and Beringian remains.
 * 12,700 years ago: The currently estimated end of Clovis technology. The fluted point-making traditions evolve into the similar Folsom tradition and other local fluted styles such as Eastern Fluted points in the eastern United States. This date also coincides with both the onset of the Younger Dryas and the extinction of large megafauna.

Post-Clovis

 * 12,845–12,770 years ago: Most recent date range for the Folsom tradition. Folsom points only lasted half a millennium before evolving into other smaller points. Meanwhile, Western Stemmed points continued to be made well into the Archaic. The discovery of Folsom points in 1927 was the first empirical evidence of an ancient human presence in the Americas and definitively overturned the then-scientific consensus of humans only arriving in America in the past 3,000 years.
 * 12,500 years ago: The earliest dates for Charlie Lake Cave, a site in the ice-free corridor containing fluted points similar to Clovis or Folsom points.
 * 12,400 - 10,000 years ago: Fluted points reach the Serpentine Hot Springs in western Alaska. It is thought that Clovis-descended people migrated, or knowledge of Clovis-style points were transmitted, from south to north into Alaska via the ice-free corridor.

I'll periodize this later

 * 10,900–10,300 years ago (8900 to 8300 BCE): The Indigenous peoples of the southwestern Amazon basin domesticate cassava, the first domestic crop in the New World, followed by squash and dozens of tree species. They also begin intensively modifying the Amazonian landscape, foresting open savannahs and permanently increasing the biomass and biodiversity of the modern Amazon rainforest.
 * 9,000 years ago (7000 BCE): Maize is domesticated in southern Mexico from the wild (and significantly different) teosinte and quickly becomes the dominant staple of Mesoamerica, heralding the beginning of agriculture and further domestications in the region.
 * 8,000–7,000 years ago (6000 - 5000 BCE):: The earliest New World ceramics are created in the Amazon basin.
 * 7,700 years ago (5700 BCE: Oregon's Mount Mazama erupts, creating Crater Lake. The violent eruption and collapse of the volcano was recorded in Klamath oral history.
 * 7,000 years ago (5000 BCE): Doedicurus, a club-tailed glyptodont (an armadillo relative) goes extinct; its most recent known remains show signs of butchering.


 * 6,080 years ago (4130 BCE): Toggling harpoons are invented somewhere in eastern Siberia, spreading south into Japan and east into North America, where they are ancestral to the sophisticated designs of the Inuit and later European whalers.
 * 6,000 to 4,000 years ago (4000–2000 BCE): The Dene-Yeniseian languages split into Na-Dene in North America and Yeniseian languages in Siberia. The connection is commonly thought to have been the result of a back-migration of early American Indians in Beringia back into Siberia, forming the Yeniseian peoples that were once widespread throughout Eurasia. However, recent studies indicating the existence of a linguistic and technological continuum extending into the Common Era make the directionality of migration and the homeland of Dene-Yeniseian more difficult to determine.
 * 5,600 years ago (3600 BCE): The first monumental buildings are constructed in Sechin Bajo, an urban center in what is now coastal Peru. It belonged to the Casma–Sechin culture, possibly the oldest civilization in the Americas.