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An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene
Holocene
interglacial began at the end of the Pleistocene, about 11,700 years ago.

Contents

1 Interglacials during the Pleistocene 2 Interglacial
Interglacial
optimum 3 See also 4 References

Interglacials during the Pleistocene[edit]

Life timeline

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Single-celled life

photosynthesis

Eukaryotes

Multicellular life

Land life

Dinosaurs    

Mammals

Flowers

 

Earliest Earth (−4540)

Earliest water

Earliest life

LHB meteorites

Earliest oxygen

Atmospheric oxygen

Oxygen crisis

Earliest sexual reproduction

Ediacara biota

Cambrian explosion

Earliest humans

P h a n e r o z o i c

P r o t e r o z o i c

A r c h e a n

H a d e a n

Pongola

Huronian

Cryogenian

Andean

Karoo

Quaternary

Axis scale: million years Orange labels: ice ages. Also see: Human
Human
timeline and Nature timeline

During the 2.5 million year span of the Pleistocene, numerous glacials, or significant advances of continental ice sheets in North America and Europe, have occurred at intervals of approximately 40,000 to 100,000 years. These long glacial periods were separated by more temperate and shorter interglacials. During interglacials, such as the present one, the climate warms and the tundra recedes polewards following the ice sheets. Forests return to areas that once supported tundra vegetation. Interglacials are identified on land or in shallow epicontinental seas by their paleontology. Floral and faunal remains of species pointing to temperate climate and indicating a specific age are used to identify particular interglacials. Commonly used are mammalian and molluscan species, pollen and plant macro-remains (seeds and fruits). However, many other fossil remains may be helpful: insects, ostracods, foraminifera, diatoms, etc. Recently, ice cores and ocean sediment cores provide more quantitative and accurately dated evidence for temperatures and total ice volumes. The interglacials and glacials coincide with cyclic changes in the Earth's orbit. Three orbital variations contribute to interglacials. The first is a change in the Earth's orbit
Earth's orbit
around the sun, or eccentricity. The second is a shift in the tilt of the Earth's axis, the obliquity. The third is precession, or wobbling motion of Earth's axis.[1] Warm summers in the Southern hemisphere occur when that hemisphere is tilted toward the sun and the Earth is nearest the sun in its elliptical orbit. Cool summers occur when the Earth is farthest from the sun during that season. These effects are more pronounced when the eccentricity of the orbit is large. When the obliquity is large, seasonal changes are more extreme.[2] Interglacials are a useful tool for geological mapping and also for anthropologists, as they can be used as a dating method for hominid fossils.[3] Brief periods of milder climate that occurred during the last glacial are called interstadials. Most (not all) interstadials are shorter than interglacials. Interstadial climate may have been relatively warm but this is not necessarily so. Because the colder periods (stadials) have often been very dry, wetter (so not necessarily warmer) periods have been registered in the sedimentary record as interstadials as well. The oxygen isotope ratio obtained from seabed sediment core samples, a proxy for average global temperature, is an important source of information about changes in the climate of the earth. Interglacial
Interglacial
optimum[edit] An interglacial optimum, or climatic optimum of an interglacial, is the period within an interglacial that experienced the most 'favourable' climate that occurred during that interglacial, often during the middle part. The climatic optimum of an interglacial follows, and is followed by, phases that are within the same interglacial and that experienced a less favourable climate (but nevertheless a 'better' climate than during the preceding/succeeding glacials). During an interglacial optimum, sea levels rise to their highest values, but not necessarily exactly at the same time as the climatic optimum. In the present interglacial, the Holocene, the climatic optimum occurred during the Subboreal
Subboreal
(5 to 2.5 ka BP, which corresponds to 3000 BC-500 BC) and Atlanticum
Atlanticum
(9 to 5 ka, which corresponds to roughly 7000 BC-3000 BC). Our current climatic phase following this climatic optimum is still within the same interglacial (the Holocene). This warm period was followed by a gradual decline until about 2,000 years ago, with another warm period until the Little Ice Age (1250-1850). The preceding interglacial optimum occurred during the Late Pleistocene
Pleistocene
Eemian Stage, 131–114 ka. During the Eemian the climatic optimum took place during pollen zone E4 in the type area (city of Amersfoort, Netherlands). Here this zone is characterized by the expansion of Quercus
Quercus
(oak), Corylus
Corylus
(hazel), Taxus, Ulmus
Ulmus
(elm), Fraxinus
Fraxinus
(ash), Carpinus
Carpinus
(hornbeam), and Picea
Picea
(spruce). During the Eemian Stage
Eemian Stage
sea level was about 8 meters higher than today and the water temperature of the North Sea
North Sea
was about 2 °C higher than at present. See also[edit]

Greenhouse and icehouse Earth Milankovitch cycles Snowball Earth Interstadial periods Last glacial maximum

References[edit]

^ Eldredge, S. "Ice Ages – What are they and what causes them?". Utah Geological Survey. Retrieved 2 March 2013.  ^ Rieke, G. "Long Term Climate".  ^ Kottak, Conard Phillip (2005). Window on Humanity. New York: McGraw-Hill. ISBN 0-07-289028-2. 

v t e

Greenhouse and Icehouse Earth

Greenhouse Earth Tropical temperatures may reach poles

Icehouse Earth Global climate during an ice age

Snowball Earth Earth's surface entirely or nearly frozen over

Warm period Interglacials Stadials and Interstadials Glacials Cold period

v t e

Continental glaciations

General

Canadian Shield Glacial
Glacial
history of Minnesota Lake Agassiz Lake Chicago Lake Tight Last Glacial
Glacial
Maximum Laurentide Ice Sheet List of prehistoric lakes Post-glacial rebound Proglacial lake Teays River Timeline of glaciation

Landforms

Erosional

Fjord Glacial
Glacial
striae Ribbon lake Roche moutonnée Tunnel valley U-shaped valley

Depositional

Drumlin Drumlin
Drumlin
field Erratic block Moraine Pulju moraine Rogen moraine Terminal moraine Till plain Veiki moraine

Glacifluvial

Diluvium Esker Giant current ripples Kame Kame
Kame
delta Kettle hole Outwash fan Sandur

North American places

Canada

Arrowhead Provincial Park, Ontario Big Rock (glacial erratic), Alberta Cypress Hills (Canada), Saskatchewan Eramosa River, Ontario Eskers Provincial Park, British Columbia Foothills Erratics Train, Alberta Lion's Head Provincial Park, Ontario Origin of the Oak Ridges Moraine, Ontario Ovayok Territorial Park, Nunavut

United States

Chippewa Moraine
Moraine
State Recreation Area, Wisconsin Coteau des Prairies, South Dakota Devil's Lake State Park, Wisconsin Glacial
Glacial
Lake Wisconsin, Wisconsin Glacial
Glacial
Lakes State Park, Minnesota Horicon Marsh
Horicon Marsh
State Wildlife Area, Wisconsin Ice Age Floods National Geologic Trail, Idaho, Oregon & Washington Ice Age National Scientific Reserve, Wisconsin Ice Age Trail, Wisconsin Interstate State Park, Minnesota & Wisconsin Kelleys Island, Ohio Kettle Moraine
Moraine
State Forest, Wisconsin Lake Bonneville, Utah Lake Lahontan, Nevada Lake Missoula, Montana Mill Bluff State Park, Wisconsin Oneida Lake, New York Two Creeks Buried Forest State Natural Area, Wisconsin Withrow Moraine
Moraine
and Jameson Lake Drumlin
Drumlin
Field, Washington Yosemite National Park, California

Eurasian and Antarctic places

Antarctica Hardangerfjord Killary Harbour Lambert Glacier Monte Rosa Ross Ice Shelf Svalbard

Time periods

Illinoian Stage Interglacial Interstadial Last glacial period Little Ice Age Older Dryas Pleistocene Pre-Illinoian Stage Quaternary glaciation Sangamonian Stage Wisconsin glaciation Younger Dryas

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