Pleistocene

The Pleistocene is a geological epoch from the Cenozoic Era, which lasted from about 2.6 million to 11,700 years ago, spanning the world's most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last Ice Age and also with the end of the Paleolithic age used in archaeology.

Etymology and definition

The name Pleistocene is derived from the Greek pleistos (most) and kainos (new). The Pleistocene has been dated from 2.588 million (±0.005) to 11,700 years before present (BP), with the end date expressed in radiocarbon years as 10,000 carbon-14 years BP. It covers most of the latest period of repeated glaciation, up to and including the Younger Dryas cold spell.

Climate and geography

The Pleistocene climate was marked by repeated glacial cycles where continental glaciers pushed to the 40th parallel in some places. It is estimated that, at maximum glacial extent, 30% of the Earth's surface was covered by ice. In addition, a zone of permafrost stretched southward from the edge of the glacial sheet, a few hundred kilometers in North America, and several hundred in Eurasia. The mean annual temperature at the edge of the ice was −6 °C (21 °F); at the edge of the permafrost, 0 °C (32 °F).

Flora and fauna

The Pleistocene was characterized by the presence of large land mammals, including mammoths, mastodons, saber-toothed cats, giant ground sloths, and others. The megafauna extinction occurred between the end of the Pleistocene and the early Holocene.

Human evolution

The Pleistocene is the first epoch to witness the evolution and expansion of Homo sapiens. Archaeological and genetic data suggest that the source populations of Paleolithic humans survived in sparsely wooded areas and dispersed through areas of high primary productivity while avoiding dense forest cover.

See also

• Ice Age
• Paleolithic
• Holocene
• Glaciation

References

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  Temperature from 20,000 to 10,000 years ago - recovery from ice age