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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) was the
interglacial period
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 in ...
which began about 130,000 years ago at the end of the
Penultimate Glacial Period
The Penultimate Glacial Period (PGP) is the glacial age that occurred before the Last Glacial Period. The penultimate glacial period is officially unnamed just like the Last Glacial Period. The word ''penultimate'' simply means second to last. ...
and ended about 115,000 years ago at the beginning of the
Last Glacial Period. It corresponds to
Marine Isotope Stage 5e
Marine Isotope Stage 5 or MIS 5 is a marine isotope stage in the geologic temperature record, between 130,000 and 80,000 years ago. Sub-stage MIS 5e, called the Eemian or Ipswichian, covers the last major interglacial period before the Holocene, w ...
. Although sometimes referred to as the "last interglacial" (in the "most recent previous" sense of "last"), it was the second-to-latest interglacial period of the current Ice Age, the most recent being the
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
which extends to the present day (having followed the
last glacial period). The prevailing Eemian climate was, on average, around 1 to 2 degrees Celsius (1.8 to 3.6 Fahrenheit) warmer than that of the Holocene. During the Eemian, the proportion of in the atmosphere was about 280 parts per million.
The Eemian is known as the Ipswichian in the
UK, the Mikulin interglacial in
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
, the Valdivia interglacial in
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
and the Riss-Würm interglacial in the
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Swi ...
. Depending on how a specific publication defines the Sangamonian Stage of
North America, the Eemian is equivalent to either all or part of it.
The period falls into the
Middle Paleolithic and is of some interest for the evolution of
anatomically modern human
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...
s, who were present in
Western Asia
Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Ana ...
(
Skhul and Qafzeh hominins
The Skhul/Qafzeh hominins or Qafzeh–Skhul early modern humans are hominin fossils discovered in Es-Skhul and Qafzeh caves in Israel. They are today classified as ''Homo sapiens'', among the earliest of their species in Eurasia. Skhul Cave ...
) as well as in
Southern Africa
Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number o ...
by this time, representing the earliest split of modern human populations that persists to the present time (associated with
mitochondrial haplogroup L0).
Climate
Global temperatures
The Eemian climate is believed to have been warmer than the current Holocene. Changes in the Earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as
Milankovitch cycles
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term was coined and named after Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he hypot ...
, probably led to greater seasonal temperature variations in the Northern Hemisphere. During summer months, temperatures in the Arctic region were about 2-4 °C higher than today. The warmest peak of the Eemian was around 125,000 years ago, when forests reached as far north as
North Cape, Norway
North Cape ( no, Nordkapp; sme, Davvenjárga) is a cape on the northern coast of the island of Magerøya in Northern Norway. The cape is in Nordkapp Municipality in Troms og Finnmark county, Norway. The European route E69 highway has its nort ...
(which is now
tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
) well above the
Arctic Circle at .
Hardwood trees such as
hazel and
oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
grew as far north as
Oulu, Finland.
At the peak of the Eemian, the Northern Hemisphere winters were generally warmer and wetter than now, though some areas were actually slightly cooler than today. The
hippopotamus
The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extan ...
was distributed as far north as the rivers
Rhine
), Surselva, Graubünden, Switzerland
, source1_coordinates=
, source1_elevation =
, source2 = Rein Posteriur/Hinterrhein
, source2_location = Paradies Glacier, Graubünden, Switzerland
, source2_coordinates=
, so ...
and
Thames
The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the R ...
. Trees grew as far north as southern
Baffin Island in the
Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
Arctic Archipelago: currently, the northern limit is further south at
Kuujjuaq
Kuujjuaq (; iu, ᑰᑦᔪᐊᖅ, i=no or iu, ᑰᔾᔪᐊᖅ, i=no, label=none, "Great River"), formerly known as and by other names, is a former Hudson's Bay Company outpost at the mouth of the Koksoak River on Ungava Bay that has become ...
in northern
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
. Coastal Alaska was warm enough during the summer due to reduced sea ice in the Arctic Ocean to allow
Saint Lawrence Island (now tundra) to have boreal forest, although inadequate precipitation caused a reduction in the forest cover in interior Alaska and Yukon Territory despite warmer conditions. The prairie-forest boundary in the
Great Plains of the
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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
lay further west near
Lubbock, Texas, whereas the current boundary is near
Dallas
Dallas () is the List of municipalities in Texas, third largest city in Texas and the largest city in the Dallas–Fort Worth metroplex, the List of metropolitan statistical areas, fourth-largest metropolitan area in the United States at 7.5 ...
. The period closed as temperatures steadily fell to conditions cooler and drier than the present, with a 468-year-long aridity pulse in central Europe at about 116,000 BC, and by 112,000 BC, a
glacial period
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...
had returned.
Kaspar ''et al.'' (GRL, 2005) performed a comparison of a coupled
general circulation model
A general circulation model (GCM) is a type of climate model. It employs a mathematical model of the general circulation of a planetary atmosphere or ocean. It uses the Navier–Stokes equations on a rotating sphere with thermodynamic ter ...
(GCM) with reconstructed Eemian temperatures for Europe. Central Europe (north of the Alps) was found to be warmer than present; south of the Alps, conditions were 1–2 °C cooler than today. The model (generated using observed greenhouse gas concentrations and Eemian orbital parameters) generally reproduces these observations, leading them to conclude that these factors are enough to explain the Eemian temperatures.
A 2018 study based on soil samples from
Sokli in northern
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
identified abrupt cold spells ca. 120,000 years ago caused by shifts in the
North Atlantic Current
The North Atlantic Current (NAC), also known as North Atlantic Drift and North Atlantic Sea Movement, is a powerful warm western boundary current within the Atlantic Ocean that extends the Gulf Stream northeastward.
The NAC originates from where ...
, lasting hundreds of years and causing temperature drops of a few degrees and vegetation changes in these regions.
Sea level
Sea level at peak was probably higher than today, with Greenland contributing , thermal expansion and mountain glaciers contributing up to , and an uncertain contribution from Antarctica. Recent research on marine sediment cores offshore of the West Antarctic Ice Sheet suggest that the sheet melted during the Eemian, and that ocean waters rose as fast as 2.5 meters per century. Global mean
sea surface temperature
Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between and below the sea surface. Air mas ...
s are thought to have been higher than in the Holocene, but not by enough to explain the rise in sea level through thermal expansion alone, and so melting of polar ice caps must also have occurred. Because of the sea level drop since the Eemian, exposed fossil coral reefs are common in the tropics, especially in the Caribbean and along the Red Sea coastlines. These reefs often contain internal erosion surfaces showing significant sea level instability during the Eemian.
A 2007 study found evidence that the Greenland ice core site
Dye 3
Dye 3 is an ice core site and previously part of the DYE section of the Distant Early Warning (DEW) line, located at (, 2480 masl) in Greenland. As a DEW line base, it was disbanded in years 1990/1991.
An ice core is a core sample from the accumu ...
was glaciated during the Eemian, which implies that Greenland could have contributed at most to
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
.
Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swe ...
was an island. Vast areas of northwestern Europe and the
West Siberian Plain
The West Siberian Plain (russian: За́падно-Сиби́рская равни́на ''Zapadno-Sibirskaya ravnina'') is a large plain that occupies the western portion of Siberia, between the Ural Mountains in the west and the Yenisei River ...
were inundated.
Definition of the Eemian
The Eemian Stage was first recognized from
borehole
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petrol ...
s in the area of the city of
Amersfoort
Amersfoort () is a city and municipality in the province of Utrecht, Netherlands, about 20 km from the city of Utrecht and 40 km south east of Amsterdam. As of 1 December 2021, the municipality had a population of 158,531, making it the second- ...
,
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
, by
Pieter Harting
Pieter Harting (27 February 1812 – 3 December 1885) was a Dutch biologist and naturalist, born in Rotterdam. He made contributions in a number of scientific disciplines, and is remembered for his work in the fields of microscopy, hydrology, ...
(1875). He named the beds "Système Eémien", after the river
Eem
The Eem (; formerly the Amer) is a river in the central Netherlands with a length of approximately .
The river is fed by the Vallei Canal and a number of Veluwe creeks, the most important of which are the Heiligenberger Beek, the Barneveldse Beek ...
on which Amersfoort is located. Harting noticed the marine molluscan assemblages to be very different from the modern fauna of the
North Sea
The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
. Many species from the Eemian layers nowadays show a much more southern distribution, ranging from South of the
Strait of Dover to
Portugal
Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
(
Lusitanian faunal province) and even into the
Mediterranean
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...
(Mediterranean faunal province). More information on the molluscan assemblages is given by Lorié (1887), and Spaink (1958). Since their discovery, Eemian beds in the Netherlands have mainly been recognized by their marine molluscan content combined with their stratigraphical position and other palaeontology. The marine beds there are often underlain by
till
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
s that are considered to date from the
Saalian
The Saale glaciation or Saale Glaciation, sometimes referred to as the Saalian glaciation, Saale cold period (german: Saale-Kaltzeit), Saale complex (''Saale-Komplex'') or Saale glacial stage (''Saale-Glazial'', colloquially also the ''Saale-Eiszei ...
, and overlain by local fresh water or wind-blown deposits from the
Weichselian
The Weichselian glaciation was the last glacial period and its associated glaciation in northern parts of Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice sheet) ...
. In contrast to e.g. the deposits in Denmark, the Eemian deposits in the type area have never been found overlain by tills, nor in ice-pushed positions.
Van Voorthuysen (1958) described the
foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly ...
from the type site, whereas Zagwijn (1961) published the
palynology
Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposit ...
, providing a subdivision of this stage into pollen stages. At the end of the 20th century, the
type site
In archaeology, a type site is the site used to define a particular archaeological culture or other typological unit, which is often named after it. For example, discoveries at La Tène and Hallstatt led scholars to divide the European Iron A ...
was re-investigated using old and new data in a multi-disciplinary approach (Cleveringa et al., 2000). At the same time a
parastratotype was selected in the
Amsterdam
Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the capital and most populous city of the Netherlands, with The Hague being the seat of government. It has a population of 907,976 within the city proper, 1,558,755 in the urban ar ...
glacial basin in the Amsterdam-Terminal borehole and was the subject of a multidisciplinary investigation (Van Leeuwen, et al., 2000). These authors also published a
U/Th age for late Eemian deposits from this borehole of 118,200 ± 6,300 years ago. A historical review of Dutch Eemian research is provided by Bosch, Cleveringa and Meijer, 2000.
See also
*
Marine Isotope Stage 5
Marine Isotope Stage 5 or MIS 5 is a marine isotope stage in the geologic temperature record, between 130,000 and 80,000 years ago. Sub-stage MIS 5e, called the Eemian or Ipswichian, covers the last major interglacial period before the Holocene, w ...
*
Paleoclimatology
Paleoclimatology (American and British English spelling differences, British spelling, palaeoclimatology) is the study of climates for which direct measurements were not taken. As instrumental records only span a tiny part of Earth's history, the ...
*
Timeline of glaciation
There have been five or six major ice ages in the history of Earth over the past 3 billion years.
The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago ...
References
Further reading
*
* Cleveringa, P., Meijer, T., van Leeuwen, R.J.W., de Wolf, H., Pouwer, R., Lissenberg T. and Burger, A.W., 2000.
The Eemian stratotype locality at Amersfoort in the central Netherlands: a re-evaluation of old and new data'' Geologie & Mijnbouw / Netherlands Journal of Geosciences, 79(2/3): 197–216.
* Harting, P., 1875. ''Le système Éemien'' Archives Néerlandaises Sciences Exactes et Naturelles de la Société Hollandaise des Sciences (Harlem), 10: 443–454.
* Harting, P., 1886. ''Het Eemdal en het Eemstelsel'' Album der Natuur, 1886: 95–100.
*
* Lorié, J., 1887. ''Contributions a la géologie des Pays Bas III. Le Diluvium plus récent ou sableux et le système Eémien'' Archives Teyler, Ser. II, Vol. III: 104–160.
*
* Spaink, G., 1958. ''De Nederlandse Eemlagen, I: Algemeen overzicht.'' Wetenschappelijke Mededelingen Koninklijke Nederlandse Natuurhistorische Vereniging 29, 44 pp.
* Van Leeuwen, R.J., Beets, D., Bosch, J.H.A., Burger, A.W., Cleveringa, P., van Harten, D., Herngreen, G.F.W., Langereis, C.G., Meijer, T., Pouwer, R., de Wolf, H., 2000.
Stratigraphy and integrated facies analysis of the Saalian and Eemian sediments in the Amsterdam-Terminal borehole, the Netherlands'' Geologie en Mijnbouw / Netherlands Journal of Geosciences 79, 161–196.
* Van Voorthuysen, J.H., 1958. ''Foraminiferen aus dem Eemien (Riss-Würm-Interglazial) in der Bohrung Amersfoort I (Locus Typicus). '' Mededelingen Geologische Stichting NS 11(1957), 27–39.
* Zagwijn, W.H., 1961. ''Vegetation, climate and radiocarbon datings in the Late Pleistocene of the Netherlands. Part 1: Eemian and Early Weichselian.'' Mededelingen Geologische Stichting NS 14, 15–45.
External links
www.foraminifera.eu Foraminifera (Microfossils) of the Eemian Interglacial
{{Alpine glaciations
Interglacials
Paleoclimatology
Pleistocene