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The Pleistocene ( , often referred to as the ''Ice Age'') is the geological
epoch In chronology 222px, Joseph Scaliger's ''De emendatione temporum'' (1583) began the modern science of chronology Chronology (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-E ...
that lasted from about 2,580,000 to 11,700 years ago, spanning the earth’s most recent period of repeated
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age An ice age is a long period of reduction in the temperature of Earth Earth is the third planet from the Sun and the o ...
s. Before a change finally confirmed in 2009 by the
International Union of Geological Sciences The International Union of Geological Sciences (IUGS) is an international non-governmental organization A non-governmental organization, or simply an NGO, is an that is, generally, formed independent from . They are typically s, and many o ...
, the cutoff of the Pleistocene and the preceding
Pliocene The Pliocene ( ; also Pleiocene) epoch (geology), Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58Before Present Before Present (BP) years is a time scale used mainly in archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. Archaeology is often considered a branch of socio-cultural ...
(BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the
Paleolithic The Paleolithic or Palaeolithic or Palæolithic (), also called the Old Stone Age (from Greek palaios - old, lithos - stone), is a period in prehistory Prehistory, also known as pre-literary history, is the period of human history ...
age used in
archaeology Archaeology or archeology is the study of human activity through the recovery and analysis Analysis is the process of breaking a complexity, complex topic or Substance theory, substance into smaller parts in order to gain a better underst ...
. The name is a combination of
Ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the diale ...
πλεῖστος (''pleīstos'', "most") and καινός (''kainós'' (
latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became ...

latin
ized as ''cænus''), "new". At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the
Isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lamè Kara ...
, causing a faunal interchange between the two regions and changing
ocean circulation An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk moveme ...
patterns, with the onset of glaciation in the Northern Hemisphere occurring around 2.7 million years ago. During the Early Pleistocene (2.58–0.8 Ma),
archaic humans A number of varieties of ''Homo ''Homo'' () is the genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, definin ...
of the genus ''
Homo ''Homo'' () is the genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), cir ...

Homo
'' originated in Africa and spread throughout
Afro-Eurasia Afro-Eurasia (or Afroeurasia, Field, Henry.The University of California African Expedition: I, Egypt, ''American Anthropologist,'' New Series Vol. 50, No. 3, Part 1 (Jul. - Sep., 1948), pp. 479-493. or Eurafrasia), nicknamed the World Island, ...

Afro-Eurasia
. The end of the Early Pleistocene is marked by the
Mid-Pleistocene Transition The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary Quaternary ( ) is the current and most recent of the three Period (geology ...
, with the cyclicity of glacial cycles changing from 41,000 year cycles to 100,000 year cycles. The
Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event ...
witnessed the spread of
modern humans Early modern human (EMH) or anatomically modern human (AMH) are terms used to distinguish ''Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread of , characterized by and large, complex brains. This has enabled ...
outside of Africa as well as the extinction of all other human species. Humans also spread to the Australian continent and
the Americas The Americas (also collectively called America) is a landmass comprising the totality of North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to East and West. ''North'' ...
for the first time, co-incident with the extinction of most large bodied animals in these regions. The aridification and cooling trends of the preceding
Neogene The Neogene ( ) (informally Upper Tertiary or Late Tertiary) is a geologic period and system that spans 20.45 million years from the end of the Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Ea ...

Neogene
were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, with the sea levels being up to 120 metres lower than present at peak glaciation, allowing the connection of Asia and North America via
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 Canada is a country in the northern part of North America. Its Provinces and territori ...
and the covering of most of northern North America by the
Laurentide ice sheet The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada Canada is a country in the northern part of North America. Its Provinces and territories of Canada, ten provinces and three ...
.


Etymology

Charles Lyell Sir Charles Lyell, 1st Baronet, (14 November 1797 – 22 February 1875) was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth Earth is the third planet from the Sun and the only astro ...

Charles Lyell
introduced the term "Pleistocene" in 1839 to describe strata in
Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

Sicily
that had at least 70% of their molluscan fauna still living today. This distinguished it from the older Pliocene Epoch, which Lyell had originally thought to be the youngest fossil rock layer. He constructed the name "Pleistocene" ("most new" or "newest") from the
Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 million as of ...
πλεῖστος (''pleīstos'', "most") and καινός (''kainós'' (
latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became ...

latin
ized as ''cænus''), "new"); this contrasts with the immediately preceding
Pliocene The Pliocene ( ; also Pleiocene) epoch (geology), Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58Holocene The Holocene ( ) is the current geological epoch In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age (geology), age but shorter than a period (geology), period. The current epoch is the Holocene E ...
("wholly new" or "entirely new", from ὅλος (''hólos'', "whole") and ''kainós'')
epoch In chronology 222px, Joseph Scaliger's ''De emendatione temporum'' (1583) began the modern science of chronology Chronology (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-E ...

epoch
, which extends to the present time.


Dating

The Pleistocene has been dated from 2.580 million (±0.005) to 11,650 years BP with the end date expressed in radiocarbon years as 10,000
carbon-14 Carbon-14 (14C), or radiocarbon, is a radioactive isotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ...

carbon-14
years BP. It covers most of the latest period of repeated
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age An ice age is a long period of reduction in the temperature of Earth Earth is the third planet from the Sun and the o ...
, up to and including the
Younger Dryas The Younger Dryas (around 12,900 to 11,700 years BP) was a return to glacial conditions after the Late Glacial Interstadial The Late Glacial Interstadial (LGI) c.14,670 to c.12,890 BP represents the first ''pronounced'' warming since the end of ...
cold spell. The end of the Younger Dryas has been dated to about 9640 BC (11,654 calendar years BP). The end of the Younger Dryas is the official start of the current
Holocene Epoch The Holocene ( ) is the current geological epoch In chronology 222px, Joseph Scaliger's ''De emendatione temporum'' (1583) began the modern science of chronology Chronology (from Latin Latin (, or , ) is a classical language belongi ...
. Although it is considered an epoch, the Holocene is not significantly different from previous interglacial intervals within the Pleistocene. In the
ICS ICS may refer to: Computing * Image Cytometry Standard, a digital multidimensional image file format used in life sciences microscopy * Industrial control system, computer systems and networks used to control industrial plants and infrastructure ...
timescale, the Pleistocene is divided into four
stages Stage or stages may refer to: Acting * Stage (theatre) In theatre and performing arts, the stage (sometimes referred to as the deck in stagecraft) is a designated space for the performance of theatrical production, productions. The stage s ...
or ages, the
Gelasian The Gelasian is an age (geology), age in the international geologic timescale or a stage (stratigraphy), stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary Period/System and Pleistocene Epoch/Series. It spans t ...
, Calabrian,
Chibanian The Chibanian, widely known by its previous designation of Middle Pleistocene, is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocene Epoch withi ...
(previously the unofficial "Middle Pleistocene"), and
Upper Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of t ...
(unofficially the "Tarantian"). In addition to these international subdivisions, various regional subdivisions are often used. In 2009 the
International Union of Geological Sciences The International Union of Geological Sciences (IUGS) is an international non-governmental organization A non-governmental organization, or simply an NGO, is an that is, generally, formed independent from . They are typically s, and many o ...
(IUGS) confirmed a change in time period for the Pleistocene, changing the start date from 1.806 to 2.588 million years BP, and accepted the base of the
Gelasian The Gelasian is an age (geology), age in the international geologic timescale or a stage (stratigraphy), stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary Period/System and Pleistocene Epoch/Series. It spans t ...
as the base of the Pleistocene, namely the base of the Monte San Nicola
GSSP The 'golden spike' marking the Ediacaran GSSP A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic through Jurassic The Jurassic ( ) is a Geological period, geologic period a ...
. The start date has now been rounded down to 2.580 million years BP. The IUGS has yet to approve a
type sectionA stratotype or type section is a geological Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which i ...
,
Global Boundary Stratotype Section and Point The 'golden spike' marking the Ediacaran GSSP A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time sca ...
(GSSP), for the upper Pleistocene/Holocene boundary (''i.e.'' the upper boundary). The proposed section is the ''North Greenland Ice Core Project'' ice core 75° 06' N 42° 18' W. The lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama (C2r)
chronozone A chronozone or chron is a unit in chronostratigraphyChronostratigraphy is the branch of stratigraphy through Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the ...
, isotopic stage 103. Above this point there are notable extinctions of the calcareous nanofossils: ''Discoaster pentaradiatus'' and ''Discoaster surculus''.Gradstein, Felix M.; Ogg, James G. and Smith, A. Gilbert (eds.) (2005) ''A Geologic Time Scale 2004'' Cambridge University Press, Cambridge, UK, p. 28, The Pleistocene covers the recent period of repeated glaciations. The name
Plio-PleistoceneThe Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene The Pliocene ( ; also Pleiocene) epoch (geolog ...
has, in the past, been used to mean the last ice age. Formerly, the boundary between the two epochs was drawn at the time when the foraminiferal species ''Hyalinea baltica'' first appeared in the marine section at La Castella, Calabria, Italy; however, the revised definition of the
Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
, by pushing back the start date of the Pleistocene to 2.58 Ma, results in the inclusion of all the recent repeated glaciations within the Pleistocene. Radiocarbon dating is considered to be inaccurate beyond around 50,000 years ago.
Marine isotope stage Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from Oxygen isotope ratio cycle, oxygen isotope data reflecting changes in temp ...
s (MIS) derived from Oxygen isotopes are often used for giving approximate dates.


Deposits

Pleistocene non-marine
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently sediment transport, transported by the action of wind, water, or ice or by the force of gravity acting on the particles. ...

sediment
s are found primarily in fluvial deposits, lakebeds, slope and
loess Loess (, ; from German ''Löss'' ) is a clastic, predominantly silt-sized sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently sediment transport, transported by ...
deposits as well as in the large amounts of material moved about by glaciers. Less common are
cave A cave or cavern is a natural void in the Earth#Surface, ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can also refer to much small ...

cave
deposits,
travertine Travertine ( ) is a form of terrestrial limestone Limestone is a common type of carbonate In chemistry, a carbonate is a salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the l ...

travertine
s and volcanic deposits (lavas, ashes). Pleistocene marine deposits are found primarily in shallow marine basins mostly (but with important exceptions) in areas within a few tens of kilometers of the modern shoreline. In a few geologically active areas such as the
Southern California Southern California (sometimes known as SoCal; es, Sur de California) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California California is a in the . With over 39.3million resi ...

Southern California
coast, Pleistocene marine deposits may be found at elevations of several hundred meters.


Paleogeography and climate

The modern
continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of th ...

continent
s were essentially at their present positions during the Pleistocene, the plates upon which they sit probably having moved no more than relative to each other since the beginning of the period. In glacial periods, the sea level would drop by over during peak glaciation, exposing large areas of present
continental shelf A continental shelf is a portion of a continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth descriptio ...

continental shelf
as dry land. According to
Mark Lynas Mark Lynas (born 1973) is a British author and journalist whose work is focused on environmentalism Environmentalism or environmental rights is a broad philosophy Philosophy (from , ) is the study of general and fundamental questio ...

Mark Lynas
(through collected data), the Pleistocene's overall climate could be characterized as a continuous
El Niño es, El Niño, translation=The Boy (; ) is the warm phase of the El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the Tropics, tropical easte ...
with
trade winds The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere The Northern Hemisphere is the half of E ...
in the south
Pacific The Pacific Ocean is the largest and deepest of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. ...

Pacific
weakening or heading east, warm air rising near
Peru , , image_flag = Flag_of_Peru.svg , image_coat = Escudo_nacional_del_Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (device), National seal , national_mott ...

Peru
, warm water spreading from the west Pacific and the
Indian Ocean The Indian Ocean is the third-largest of the world's five ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surface of and contains 97% of . Another definition is "any of the large ...

Indian Ocean
to the east Pacific, and other El Niño markers.


Glacial features

Pleistocene climate was marked by repeated glacial cycles in which
continental glacier In glaciology Lateral moraine on a glacier joining the Gorner Glacier, Zermatt">Gorner_Glacier.html" ;"title="moraine on a glacier joining the Gorner Glacier">moraine on a glacier joining the Gorner Glacier, Zermatt, Swiss Alps. The moraine is ...
s pushed to the 40th
parallel Parallel may refer to: Computing * Parallel algorithm In computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their a ...
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 Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surfa ...

permafrost
stretched southward from the edge of the glacial sheet, a few hundred kilometres in
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
, and several hundred in
Eurasia Eurasia () is the largest continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a ...

Eurasia
. The mean annual temperature at the edge of the ice was ; at the edge of the permafrost, . Each glacial advance tied up huge volumes of water in continental ice sheets thick, resulting in temporary sea-level drops of or more over the entire surface of the Earth. During interglacial times, such as at present, drowned coastlines were common, mitigated by isostatic or other emergent motion of some regions. The effects of glaciation were global.
Antarctica Antarctica ( or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Oc ...

Antarctica
was ice-bound throughout the Pleistocene as well as the preceding Pliocene. The
Andes The Andes, Andes Mountains or Andean Mountains ( es, Cordillera de los Andes) are the List of mountain ranges#Mountain ranges by length, longest continental mountain range in the world, forming a continuous highland along the western edge of Sou ...

Andes
were covered in the south by the
Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America South America is a continent A continent is one of several large landmasses. Generally identified by convention (norm), convent ...

Patagonia
n ice cap. There were glaciers in
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
and
Tasmania Tasmania (), abbreviated as TAS, is an island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atol ...
. The current decaying glaciers of
Mount Kenya Mount Kenya is the highest mountain in Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu "Ee Mungu Nguvu Yetu" (, ) is the national anthem of Kenya. History "Ee Mungu Nguvu Yetu"'s lyrics were originally written in Swahili la ...

Mount Kenya
,
Mount Kilimanjaro Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest African mountains, mountain in Africa and the highest single free-standing mountain in the world: above sea le ...

Mount Kilimanjaro
, and the
Ruwenzori Range The Ruwenzori, also spelled Rwenzori and Rwenjura, are a range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a ...
in east and central Africa were larger. Glaciers existed in the mountains of
Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country A landlocked country is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the ...

Ethiopia
and to the west in the
Atlas mountains The Atlas Mountains ( ar, جِبَال ٱلْأَطْلَس, jibāl al-ʾaṭlas /ʒibaːl al atˤlas/, Tamazight The Berber languages, also known as the Amazigh languages (Berber name: , ; Neo-Tifinagh: ⵜⴰⵎⴰⵣⵉⵖⵜ, Tuareg Tifin ...

Atlas mountains
. In the northern hemisphere, many glaciers fused into one. The Cordilleran Ice Sheet covered the North American northwest; the east was covered by the Laurentide. The Fenno-Scandian ice sheet rested on
northern Europe Northern Europe is the northern region of Europe. Narrower definitions may describe Northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other geographic ...
, including much of Great Britain; the Alpine ice sheet on the
Alps The Alps ; german: Alpen ; it, Alpi ; rm, Alps; sl, Alpe ) are the highest and most extensive mountain range A mountain range is a series of mountains ranged in a line and connected by high ground. A mountain system or mountain belt ...

Alps
. Scattered domes stretched across
Siberia Siberia (; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of R ...

Siberia
and the Arctic shelf. The northern seas were ice-covered. South of the ice sheets large lakes accumulated because outlets were blocked and the cooler air slowed evaporation. When the Laurentide Ice Sheet retreated, north-central North America was totally covered by
Lake Agassiz Lake Agassiz was a very large glacial lake in central North America North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be described as the northern subcontine ...
. Over a hundred basins, now dry or nearly so, were overflowing in the North American west.
Lake Bonneville Lake Bonneville was the largest Late 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 per ...
, for example, stood where
Great Salt Lake The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the Western Hemisphere, and the eighth-largest terminal lake in the world. In an average year the lake covers an area of approximat ...

Great Salt Lake
now does. In Eurasia, large lakes developed as a result of the runoff from the glaciers. Rivers were larger, had a more copious flow, and were braided. African lakes were fuller, apparently from decreased evaporation. Deserts, on the other hand, were drier and more extensive. Rainfall was lower because of the decreases in oceanic and other evaporation. It has been estimated that during the Pleistocene, the
East Antarctic Ice Sheet The East Antarctic Ice Sheet (EAIS) is one of two large ice sheets in Antarctica Antarctica ( or ) is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, al ...
thinned by at least 500 meters, and that thinning since the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets In glaciology Lateral moraine on a glacier joining the Gorner Glacier, Zermatt">Gorner_Gla ...
is less than 50 meters and probably started after ca 14 ka.


Major events

Over 11 major glacial events have been identified, as well as many minor glacial events. A major glacial event is a general glacial excursion, termed a "glacial." Glacials are separated by "interglacials". During a glacial, the glacier experiences minor advances and retreats. The minor excursion is a "stadial"; times between stadials are "interstadials". These events are defined differently in different regions of the glacial range, which have their own glacial history depending on latitude, terrain and climate. There is a general correspondence between glacials in different regions. Investigators often interchange the names if the glacial geology of a region is in the process of being defined. However, it is generally incorrect to apply the name of a glacial in one region to another. For most of the 20th century only a few regions had been studied and the names were relatively few. Today the geologists of different nations are taking more of an interest in Pleistocene glaciology. As a consequence, the number of names is expanding rapidly and will continue to expand. Many of the advances and stadials remain unnamed. Also, the terrestrial evidence for some of them has been erased or obscured by larger ones, but evidence remains from the study of cyclical climate changes. The glacials in the following tables show ''historical'' usages, are a simplification of a much more complex cycle of variation in climate and terrain, and are generally no longer used. These names have been abandoned in favor of numeric data because many of the correlations were found to be either inexact or incorrect and more than four major glacials have been recognized since the historical terminology was established. Corresponding to the terms glacial and interglacial, the terms pluvial and interpluvial are in use (Latin: ''pluvia'', rain). A pluvial is a warmer period of increased rainfall; an interpluvial, of decreased rainfall. Formerly a pluvial was thought to correspond to a glacial in regions not iced, and in some cases it does. Rainfall is cyclical also. Pluvials and interpluvials are widespread. There is no systematic correspondence of pluvials to glacials, however. Moreover, regional pluvials do not correspond to each other globally. For example, some have used the term "Riss pluvial" in Egyptian contexts. Any coincidence is an accident of regional factors. Only a few of the names for pluvials in restricted regions have been stratigraphically defined.


Palaeocycles

The sum of transient factors acting at the Earth's surface is cyclical: climate, ocean currents and other movements, wind currents, temperature, etc. The waveform response comes from the underlying cyclical motions of the planet, which eventually drag all the transients into harmony with them. The repeated glaciations of the Pleistocene were caused by the same factors. The
Mid-Pleistocene Transition The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary Quaternary ( ) is the current and most recent of the three Period (geology ...
, approximately one million years ago, saw a change from low-amplitude glacial cycles with a dominant periodicity of 41,000 years to asymmetric high-amplitude cycles dominated by a periodicity of 100,000 years. However, a 2020 study concluded that ice age terminations might have been influenced by
obliquity In astronomy Astronomy (from el, ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that studies astronomical object, celestial objects and celestial event, phenomena. It uses mat ...
since the Mid-Pleistocene Transition, which caused stronger summers in the
Northern Hemisphere The Northern Hemisphere is the half of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remain ...

Northern Hemisphere
.


Milankovitch cycles

Glaciation in the Pleistocene was a series of glacials and interglacials, stadials and interstadials, mirroring periodic changes in climate. The main factor at work in climate cycling is now believed to be
Milankovitch cycles Milankovitch cycles describe the collective effects of changes in the 's movements on its over thousands of years. The term is named for n and . In the 1920s, he hypothesized that variations in , , and resulted in cyclical variation in the r ...

Milankovitch cycles
. These are periodic variations in regional and planetary solar radiation reaching the Earth caused by several repeating changes in the Earth's motion. Milankovitch cycles cannot be the sole factor responsible for the variations in climate since they explain neither the long term cooling trend over the Plio-Pleistocene, nor the millennial variations in the Greenland Ice Cores. Milankovitch pacing seems to best explain glaciation events with periodicity of 100,000, 40,000, and 20,000 years. Such a pattern seems to fit the information on climate change found in oxygen isotope cores.


Oxygen isotope ratio cycles

In oxygen isotope ratio analysis, variations in the ratio of to (two
isotopes Isotopes are two or more types of atoms that have the same atomic number 300px, The Rutherford–Bohr model of the hydrogen atom () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of ...
of
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
) by
mass Mass is the quantity Quantity is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value ...
(measured by a
mass spectrometer Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio The mass-to-charge ratio (''m''/''Q'') is a physical quantity A physical quantity is a physical property of a material or system that can be Quant ...
) present in the
calcite Calcite is a carbonate mineral Carbonate minerals are those mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid E ...

calcite
of oceanic
core sample A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel Steel is an alloy A ...

core sample
s is used as a diagnostic of ancient ocean temperature change and therefore of climate change. Cold oceans are richer in , which is included in the tests of the microorganisms (
foraminifera Foraminifera (; Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...
) contributing the calcite. A more recent version of the sampling process makes use of modern glacial ice cores. Although less rich in than sea water, the snow that fell on the glacier year by year nevertheless contained and in a ratio that depended on the mean annual temperature. Temperature and climate change are cyclical when plotted on a graph of temperature versus time. Temperature coordinates are given in the form of a deviation from today's annual mean temperature, taken as zero. This sort of graph is based on another of isotope ratio versus time. Ratios are converted to a percentage difference from the ratio found in standard mean ocean water (SMOW). The graph in either form appears as a
waveform In electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons The electron is a subatomic particle In physical sciences, subatomic part ...
with
overtones An overtone is any frequency Frequency is the number of occurrences of a repeating event per unit of time A unit of time is any particular time Time is the indefinite continued sequence, progress of existence and event (philosoph ...
. One half of a period is a Marine isotopic stage (MIS). It indicates a glacial (below zero) or an interglacial (above zero). Overtones are stadials or interstadials. According to this evidence, Earth experienced 102 MIS stages beginning at about 2.588 Ma BP in the Early Pleistocene
Gelasian The Gelasian is an age (geology), age in the international geologic timescale or a stage (stratigraphy), stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary Period/System and Pleistocene Epoch/Series. It spans t ...
. Early Pleistocene stages were shallow and frequent. The latest were the most intense and most widely spaced. By convention, stages are numbered from the Holocene, which is MIS1. Glacials receive an even number; interglacials, odd. The first major glacial was MIS2-4 at about 85–11 ka BP. The largest glacials were 2, 6, 12, and 16; the warmest interglacials, 1, 5, 9 and 11. For matching of MIS numbers to named stages, see under the articles for those names.


Fauna

Both marine and continental faunas were essentially modern but with many more large land mammals such as
Mammoth A mammoth is any species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organ ...

Mammoth
s,
Mastodon A mastodon ( Greek: μαστός "breast" and ὀδούς, "tooth") is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae) that inhabited North and Central America during the late Miocene The Miocene ( ) is the first ...

Mastodon
s, ''
Diprotodon ''Diprotodon'' is an extinct genus of gigantic quadrupedal marsupial native to Australia during the Pleistocene The Pleistocene ( , often colloquially referred to as the ''Ice Age'') is the geological Epoch (geology), epoch that lasted from abo ...

Diprotodon
'', ''
Smilodon ''Smilodon'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), cir ...

Smilodon
'',
tiger The tiger (''Panthera tigris'') is the largest extant taxon, living Felidae, cat species and a member of the genus ''Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, i ...

tiger
,
lion The lion (''Panthera leo'') is a large cat The cat (''Felis catus'') is a domestic Domestic may refer to: In the home * Anything relating to the human home A home, or domicile, is a space used as a permanent or semi-perma ...

lion
,
Aurochs The aurochs (''Bos primigenius'') ( or ), also known as urus or ure, is an extinct cattle species that was first described in 1827. With a shoulder height of up to in bulls and in cows, it was one of the largest herbivores in Holocene Europe ...

Aurochs
, short-faced
bears Bears are carnivora Carnivora is an order of placental Placentalia is one of the three extant subdivisions of the class of animals Mammalia Mammals (from Latin Latin (, or , ) is a classical language belonging to the Ita ...

bears
,
giant sloth Ground sloths are a diverse group of extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the endling, last individu ...
s, ''
Gigantopithecus ''Gigantopithecus'' is an extinct genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term ma ...

Gigantopithecus
'' and others. Isolated landmasses such as
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
,
Madagascar Madagascar (; mg, Madagasikara), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), and previously known as the Malagasy Republic The Malagasy Republic ( mg, Repoblika Mal ...

Madagascar
,
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
and islands in the Pacific saw the evolution of large birds and even reptiles such as the
Elephant bird Elephant birds are members of the extinct Extinction is the termination of a kind of organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Bi ...

Elephant bird
,
moa Moa (order Order or ORDER or Orders may refer to: * Orderliness Orderliness is associated with other qualities such as cleanliness Cleanliness is both the abstract state of being clean and free from germs, dirt, trash, or waste, and the habit ...

moa
,
Haast's eagle The Haast's eagle (''Hieraaetus moorei'') is an extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous syste ...
, '' Quinkana'', ''
Megalania Megalania (''Varanus priscus'') is an extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embo ...

Megalania
'' and ''
Meiolania ''Meiolania'' ("small roamer") is an extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embod ...

Meiolania
''. The severe climatic changes during the Ice Age had major impacts on the fauna and flora. With each advance of the ice, large areas of the continents became totally depopulated, and plants and animals retreating southwards in front of the advancing glacier faced tremendous stress. The most severe stress resulted from drastic climatic changes, reduced living space, and curtailed food supply. A major extinction event of large
mammal Mammals (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
s (
megafauna In terrestrial zoology Zoology ()The pronunciation of zoology as is typically regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the anatomy, structure, embryology, evolutio ...

megafauna
), which included
mammoth A mammoth is any species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organ ...

mammoth
s,
mastodon A mastodon ( Greek: μαστός "breast" and ὀδούς, "tooth") is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae) that inhabited North and Central America during the late Miocene The Miocene ( ) is the first ...

mastodon
s,
saber-toothed cats A saber-tooth (alternatively spelled sabre-tooth) is any member of various extinct groups of predatory Predation is a biological interaction In ecology Ecology (from el, οἶκος, "house" and el, -λογία, label=none, "stud ...
, ''
glyptodon ''Glyptodon'' (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is app ...

glyptodon
s'', the
woolly rhinoceros The woolly rhinoceros (''Coelodonta antiquitatis'') is an extinct species of rhinoceros A rhinoceros (, , ), commonly abbreviated to rhino, is a member of any of the five Extant taxon, extant species of odd-toed ungulates in the family (biol ...
, various
giraffid The Giraffidae are a family (biology), family of ruminant artiodactyl mammals that share a common ancestor with cervids and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant genera, ...
s, such as the
Sivatherium ''Sivatherium'' ("Shiva's beast", from Shiva Shiva (; sa, शिव, lit=The Auspicious One, Śiva ), also known as Mahadeva (; ɐɦaːd̪eːʋɐ, is one of the Hindu deities, principal deities of Hinduism. He is the God, Supreme Being ...
;
ground sloth Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. The term is used as a reference for all extinct sloths because of the large size of the earliest forms discovered, as opposed to existing tree sloths. The ...

ground sloth
s,
Irish elk The Irish elk (''Megaloceros giganteus'') also called the giant deer or Irish deer, is an extinct species of deer in the genus ''Megaloceros'' and is one of the largest deer that ever lived. Its range extended across Eurasia during the Pleistocen ...
,
cave bear The cave bear (''Ursus spelaeus'') was a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the l ...
s,
Gomphothere Gomphotheres are any members of the diverse, extinct Extinction is the termination of a kind of organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system th ...
s,
dire wolves The dire wolf (''Aenocyon dirus''From Greek αἰνός (ainós) 'dreadful' + κύων (kúōn) 'dog' and Latin ''dīrus'' 'fearsome' ) is an extinct canine. It is one of the most famous prehistoric carnivore A carnivore , meaning "meat ...
, and short-faced bears, began late in the Pleistocene and continued into the Holocene.
Neanderthal Neanderthals (, also Neandertals, ''Homo neanderthalensis'' or ''Homo sapiens neanderthalensis'') are an extinct species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an org ...
s also became extinct during this period. At the end of the last ice age, cold-blooded animals, smaller mammals like
wood mice The wood mouse (''Apodemus sylvaticus'') is a Muridae, murid rodent native to Europe and northwestern Africa. It is closely related to the yellow-necked mouse (''Apodemus flavicollis'') but differs in that it has no band of yellow fur around the ...

wood mice
, migratory birds, and swifter animals like
whitetail deer The white-tailed deer (''Odocoileus virginianus''), also known as the whitetail or Virginia deer, is a medium-sized deer Deer or true deer are hoofed ruminant Ruminants are herbivorous mammals of the suborder Ruminantia that are able to ...

whitetail deer
had replaced the megafauna and migrated north. Late Pleistocene
bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of sheep Sheep (''Ovis aries'') are quadrupedal, ruminant mammals typically kept as livestock. Like all ruminants, sheep are members of the order(biology), order Artiodactyla, the even-toed ...

bighorn sheep
were more slender and had longer legs than their descendants today. Scientists believe that the change in predator fauna after the late Pleistocene extinctions resulted in a change of body shape as the species adapted for increased power rather than speed. The extinctions hardly affected Africa but were especially severe in
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
where native
horse The horse (''Equus ferus caballus'') is a domesticated Domestication is a sustained multi-generational relationship in which one group of organisms assumes a significant degree of influence over the reproduction and care of another group to ...

horse
s and
camel A camel is an even-toed ungulate The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, ...

camel
s were wiped out. *
Asian land mammal agesThe Asian land mammal ages, acronym ALMA, establish a geologic timescale for prehistoric Asian fauna beginning 58.7 Mya (unit), Mya during the Paleogene and continuing through to the Miocene (Aquitanian age, Aquitanian) (23.03 Ma). These periods are ...
(ALMA) include Zhoukoudianian, Nihewanian, and Yushean. *
European land mammal ages The European Land Mammal Mega Zones (abbreviation: ELMMZ, more commonly known as European land mammal ages or ELMA) are zones in rock layers that have a specific assemblage of fossils (biozones) based on occurrences of fossil assemblages of European ...
(ELMA) include the
Villafranchian Villafranchian age ( ) is a period of geologic time (3.5–1.0 Ma) overlapping the end of the Pliocene and the beginning of the Pleistocene used more specifically with European Land Mammal Ages. Named by Italian geologist Lorenzo ParetoFossil Mamm ...
, Galerian, and
Aurelian Aurelian ( la, Lucius Domitius Aurelianus; 9 September 214c. October 275) was Roman emperor from 270 to 275. As emperor, he won an unprecedented series of military victories which reunited the Roman Empire after it had practically disintegrated ...
*
North American land mammal agesThe North American land mammal ages (NALMA) establishes a Geologic time scale, geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals ...
(NALMA) include
Blancan The Blancan North American Stage on the geologic timescale The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing ...
(4.75–1.8),
Irvingtonian The Irvingtonian North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), spanning from 1.9 million – 250,000 years Before Present, BP.
(1.8–0.24) and
RancholabreanThe Rancholabrean North American Land Mammal Age on the geologic timescale The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologists, paleontology, ...
(0.24–0.01) in millions of years. The Blancan extends significantly back into the Pliocene. *
South American land mammal ages The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Mya (unit), Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred ...
(SALMA) include
Uquian The Uquian age is a period of geologic time The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or e ...
(2.5–1.5),
Ensenadan The Ensenadan age is a period of geologic time The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object o ...
(1.5–0.3) and
LujanianThe Lujanian age is a period of geologic time (0.8–0.011 Ma or 800–11 tya) within the Pleistocene The Pleistocene ( , often colloquially referred to as the ''Ice Age'') is the geological Epoch (geology), epoch that lasted from about 2,580,0 ...
(0.3–0.01) in millions of years. The Uquian previously extended significantly back into the Pliocene, although the new definition places it entirely within the Pleistocene. In July 2018, a team of
Russian Russian refers to anything related to Russia, including: *Russians (русские, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *Rossiyane (россияне), Russian language term ...

Russian
scientists in collaboration with
Princeton University Princeton University is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty Springfield, after an absence of nearly tw ...

Princeton University
announced that they had brought two female
nematodes The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum In biology, a phylum (; plural The plural (sometimes list of glossing abbreviations, abbreviated ), in many languages, is one of the valu ...
frozen in
permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surfa ...

permafrost
, from around 42,000 years ago, back to life. The two nematodes, at the time, were the oldest confirmed living animals on the planet. File:Ice age fauna of northern Spain - Mauricio Antón.jpg, Pleistocene of
Northern Spain Spain , * gl, Reino de España, * oc, Reiaume d'Espanha, , , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = , national_anthem = , image_map = , map_caption = ...
, including
woolly mammoth The woolly mammoth (''Mammuthus primigenius'') is a species of mammoth A mammoth is any species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a u ...

woolly mammoth
, cave lions eating a
reindeer The reindeer (''Rangifer tarandus''), also known as the caribou in North America, is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, boreal, and mountainous regions of northern Europe, Siberia, and North ...

reindeer
, , and
woolly rhinoceros The woolly rhinoceros (''Coelodonta antiquitatis'') is an extinct species of rhinoceros A rhinoceros (, , ), commonly abbreviated to rhino, is a member of any of the five Extant taxon, extant species of odd-toed ungulates in the family (biol ...
File:Pleistocene SA.jpg, Pleistocene of
South America South America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continent ...

South America
, including ''
Megatherium ''Megatherium'' ( from the Greek '' mega'' έγας meaning "great", and ''therion (disambiguation), therion'' ηρίον "beast") is an extinct genus of ground sloths endemic to South America that lived from the Early Pliocene through ...

Megatherium
'' and two ''
Glyptodon ''Glyptodon'' (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is app ...

Glyptodon
''


Humans

The
evolution Evolution is change in the heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from parents to their offspring; either through asexual reproduction or sexual reproduction, ...

evolution
of
anatomically modern humans Early modern human (EMH) or anatomically modern human (AMH) are terms used to distinguish ''Homo sapiens'' (the only extant Hominina species) that are Human anatomy, anatomically consistent with the Human variability, range of phenotypes seen i ...
took place during the Pleistocene. In the beginning of the Pleistocene ''
Paranthropus ''Paranthropus'' is a genus of extinct hominin which contains two widely accepted species: '' P. robustus'' and '' P. boisei''. However, the validity of ''Paranthropus'' is contested, and it is sometimes considered to be synonym (taxonomy), sy ...
'' species were still present, as well as early human ancestors, but during the lower Palaeolithic they disappeared, and the only
hominin The Hominini form a taxonomic tribe of the subfamily Homininae Homininae (), also called "African hominids" or "African apes", is a subfamily of Hominidae The Hominidae (), whose members are known as great apes or hominids (), are a t ...
species found in fossilic records is ''
Homo erectus ''Homo erectus'' (meaning "upright Body relative directions (also known as egocentric coordinates) are geometrical orientations relative to a body such as a human Humans (''Homo sapiens'') are the most abundant and widespread s ...

Homo erectus
'' for much of the Pleistocene.
Acheulean Acheulean (; also Acheulian and Mode II), from the French ''acheuléen'' after the type site of Saint-Acheul, is an archaeological industry:''Not to be confused with industrial archaeology , and a common topic of study for industrial archa ...

Acheulean
lithics Lithic may refer to: *Relating to stone tool A stone tool is, in the most general sense, any tool made either partially or entirely out of Rock (geology), stone. Although stone tool-dependent societies and cultures still exist today, most stone ...
appear along with ''Homo erectus'', some 1.8 million years ago, replacing the more primitive
Oldowan The Oldowan (or Mode I) was a widespread stone tool A stone tool is, in the most general sense, any tool made either partially or entirely out of Rock (geology), stone. Although stone tool-dependent societies and cultures still exist today, ...

Oldowan
industry used by ''
A. garhi ''Australopithecus garhi'' is a species of australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally '' Australopithecus'' ( cladistically including the genus, genera ''Ho ...
'' and by the earliest species of ''Homo''. The
Middle Paleolithic The Middle Paleolithic (or Middle Palaeolithic) is the second subdivision of the Paleolithic The Paleolithic or Palaeolithic or Palæolithic (), also called the Old Stone Age (from Greek palaios - old, lithos - stone), is a period in prehi ...
saw more varied speciation within ''Homo'', including the appearance of ''
Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedality, bipedalism and large, complex brains. This has enabled the development of advanced tools, culture, and language. Humans are highl ...

Homo sapiens
'' about 200,000 years ago. According to mitochondrial timing techniques,
modern humans Early modern human (EMH) or anatomically modern human (AMH) are terms used to distinguish ''Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread of , characterized by and large, complex brains. This has enabled ...
migrated from Africa after the
Riss glaciation The Riss glaciation, Riss Glaciation, Riss ice age, Riss Ice Age, Riss glacial or Riss Glacial (german: Riß-Kaltzeit, ', ' or (obsolete) ') is the second youngest glaciation A glacial period (alternatively glacial or glaciation) is an interval ...
in the Middle Palaeolithic during the
Eemian Stage The Eemian (also called the last interglacial, Sangamonian Stage, Ipswichian, Mikulin, Kaydaky, penultimate,NOAA - Penultimate Interglacial Period http://www.ncdc.noaa.gov/global-warming/penultimate-interglacial-period Valdivia or Riss-Würm) wa ...
, spreading all over the ice-free world during the late Pleistocene. A 2005 study posits that humans in this migration interbred with
archaic human A number of varieties of ''Homo ''Homo'' () is the that emerged in the (otherwise extinct) genus ' that encompasses the extant species ' (), plus several extinct species classified as either to or closely related to modern humans (dependin ...
forms already outside of Africa by the late Pleistocene, incorporating archaic human genetic material into the modern human gene pool.


See also

*
Climate change Contemporary climate change includes both the global warming caused by humans, and its impacts on Earth's weather patterns. There have been previous periods of climate change, but the current changes are more rapid than any known even ...
*
Pleistocene megafauna Pleistocene megafauna is the set of large animals that lived on Earth during 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, ...
*
Pleistocene Park Pleistocene Park (russian: Плейстоценовый парк, Pleystotsenovyy park) is a nature reserve on the Kolyma River south of Chersky (settlement), Chersky in the Sakha Republic, Russia, in northeastern Siberia, where an attempt is be ...

Pleistocene Park
*
Timeline of glaciation A timeline is a display of a list of events in Chronology, chronological order. It is typically a graphic design showing a long bar labelled with calendar date, dates paralleling it, and usually contemporaneous events. Timelines can use any ...


Explanatory notes


References

* Ogg, Jim (June 2004)
"Overview of Global Boundary Stratotype Sections and Points (GSSP's)"
International Commission on Stratigraphy. Accessed 20 March 2019.


External links


Late Pleistocene environments of the southern high plains
1975, edited by Wendorf and Hester.
Pleistocene Microfossils: 50+ images of Foraminifera

Stepanchuk V.N., Sapozhnykov I.V. Nature and man in the pleistocene of Ukraine. 2010

Human Timeline (Interactive)
,
National Museum of Natural History The National Museum of Natural History is a natural history museum A natural history museum or museum of natural history is a scientific institution with natural history scientific collection, collections that include current and historica ...

National Museum of Natural History
(August 2016).
Pleistocene Park: Conservation Project to Restore a Pleistocene Ecology and Protect Permafrost Soils in Northern Siberia
{{Authority control Articles which contain graphical timelines Geological epochs Quaternary geochronology