10th millennium BC
The 10th millennium BC spanned the years 10,000 BC to 9001 BC (c. 12 ka to c. 11 ka). It marks the beginning of the transition from the Palaeolithic to the Neolithic via the interim Mesolithic ( Northern Europe and Western Europe) and Ep ...
Time line chart
This time line of the geologic history of the United States chronologically lists important events occurring within the present political boundaries of
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
(including territories) before 12,000 years ago. This time line segment may include some events that occurred outside these borders that profoundly influenced later American life and its present landscape. It also includes evidence of Native American communities predating the
Clovis culture
The Clovis culture is a prehistoric Paleoamerican culture, named for distinct stone and bone tools found in close association with Pleistocene fauna, particularly two mammoths, at Blackwater Locality No. 1 near Clovis, New Mexico, in 1936 a ...
.
Because of the inaccuracies inherent in
radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The method was de ...
and other methods of interpreting the geologic (and archaeological) record, most dates in this time line represent approximations that may vary considerably from source to source. The assumptions implicit in geologic dating methods also may yield a general bias in the dating in this time line.
* 1,600,000 to 10,000 years ago: The
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
Epoch; humans arrive in North America at the end of the epoch.
* 200,000 years ago: Oldest
archaeological
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
* 50,000 years ago: Current practical limit of radiocarbon dating.
* 42,000 to 21,000 years ago: Geneticists estimate that people of eastern Siberia and Native Americans belonged to the same population.
* 41,000 years ago:
Bear
Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the No ...
remains from a cave on Prince of Wales Island, Alaska; humans visited tens of thousands of years later.
* 40,000 to 30,000 years ago: The
Australian Aborigines
Aboriginal Australians are the various Indigenous peoples of the Australian mainland and many of its islands, such as Tasmania, Fraser Island, Hinchinbrook Island, the Tiwi Islands, and Groote Eylandt, but excluding the Torres Strait Isla ...
reach their continent by boat, leading some archaeologists to suggest that the First Americans might have reached the Americas by travel overseas.
* 35,000 years ago: California linguist Johanna Nichols estimates that diversification began in the Native American people.
* 35,000 to 25,000 years ago: Humans reach far eastern Siberia opposite Alaska.
* 25,000 to 10,000 years ago: Natural land bridge of
Beringia
Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip ...
connects Siberian Far East with Alaska.
* 23,000 years ago: Cordilleran Ice Sheet closes Pacific coast to overland travel.
* 23,000 to 19,000 years ago: During these coldest millennia, glacial lobes hundreds of kilometers wide flowed into the North Pacific Ocean.
* 16,500 years ago: Solutrean Period in prehistoric Europe ends after producing artifacts vaguely similar to those of Clovis, New Mexico.
* 16,000 years ago: Earliest radiocarbon dating from the
Cactus Hill
Cactus Hill is an archaeological site in southeastern Virginia, United States, located on sand dunes above the Nottoway River about 45 miles south of Richmond. The site receives its name from the prickly pear cacti that can be found growing abunda ...
, Virginia archaeological site with human artifacts buried below Clovis fluted-point spear points.
* 15,000 years ago: First Native Americans probably have arrived in Alaska from Siberia-—possibly much earlier.
* 14,250 years ago: Unmistakable human artifacts deposited into sediments of this age at
Meadowcroft Rockshelter
Meadowcroft Rockshelter is an archaeological site located near Avella in Jefferson Township, Pennsylvania. The site is a rock shelter in a bluff overlooking Cross Creek (a tributary of the Ohio River), and contains evidence that the area may have ...
, Pennsylvania.
* 14,000 years ago: Vast North American ice sheets retreat, opening Pacific coast route southward from Alaska to overland travel.
* 14,000 to 13,000 years ago: A warming climate leaves the Pacific coast of North America ice-free during summer, opening the possibility of southward migration.
* 13,000 years ago: Asians had begun walking across the land bridge from Siberia to become the first Native Americans.
* 12,500 years ago: Radiocarbon dating of organic remains excavated at Monte Verde, Chile indicate that people lived in the Americas, probably migrating from Siberia along the Pacific coast
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...