On a geological timescale, Earth's climate has gone through considerable changes. Colder periods, during which glaciers covered more land and sea than today, are called ice ages. The last glacial period, commonly referred to as the Ice Age, began 115,000 years before present, and ended around 9,700 BC; that is 11,700 years ago.
In particular North America, Europe and Asia have traces of glaciation. Some glaciated regions are now covered with Boreal forest.
Understand
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| “ | From Ymir's flesh the earth was formed, and from his bones the hills, the heaven from the skull of that ice-cold giant, and from his blood the sea. |
” |
—Voluspa, the Elder Edda | ||
The Nordic countries were covered by ice during the last Ice Age, until 10,000 BC. The ice has set its mark on the scenery, both obvious ones and more discrete traces: enormous rocks in otherwise flat terrain (glacial erratics), polished bedrock, large potholes drilled in the bedrock by eddies in glacial rivers (giants kettles), and a hundred metre high sandy terraces at valley mouths. Fjords, such as the fjords of Norway, were also created by glacial erosion, though at a longer time scale. The rising land has lifted parts of some fjords above the sea level and in this way created picturesque lakes. Traces of the Nordic Ice Age can be found even in Germany and Poland, which have glacial erratics transported there from the former Nordic bedrock; glacial erratics are common in southern Finland.
Post-glacial rebound
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The ice pushed down Earth's crust, and it is still rising in modern times, up to one centimetre each year in the area around Kvarken between Sweden and Finland. The post-glacial rebound constantly moves the coastline; most modern settlements and farmlands in Sweden and Finland were navigable sea a few thousand years, or even less than one thousand years ago. The movement is enough for old people to remember a different shoreline from their youth.
In Norse mythology, the gods Thor and Loki visited the giant Skrymir (also referred to as Utgarda-Loki, named as such to avoid confusion with the namesake god), who gave them many challenges. Skrymir wagered that Thor, famous for his strength and thirst for beer, could not empty Skrymir's enormous drinking horn in three sips. While Thor took great effort, he failed. Skrymir revealed that he had put the spike of the horn into the sea, to prevent Thor from emptying the horn. However, the sea level had dropped since before he drank.
Destinations
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Nordic countries
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- 1 Eidfjord terraces
- Glacial potholes: A giant's kettle, also known as either a giant's cauldron (Norwegian: jettegryte), moulin pothole, or glacial pothole, is a typically large and cylindrical pothole drilled in solid rock underlying a glacier. These are common in the Nordic countries.
- 2 Rullestadjuvet jettegryter (E134 between Odda and Fjæra). The numerous potholes in Rullestad gorge are among the largest (several metres across) in Northern Europe and were created during the Ice Age. Relatively easy hike (elevation gain about 250 m) but cliffs are steep and hikes should be done in dry conditions and with good hiking shoes/boots. Free.
- 3 Mågålaupet (several linked potholes)
- 4 Helvete (several potholes)
- 5 Haukalivatnet
- 6 High Coast and Kvarken Archipelago UNESCO World Heritage Site.
- 7 Punkaharju
- 8 Salpausselkä
- 12 Simo Upthrust Park (Simon Maankohoumapuisto) (Simo, Finland). During the last ice age the kilometres-thick ice sheet caused the basement rock to depress. The Bothnian Bay area is the best place on Earth to see how it slowly rises up, nearly one centimetre a year. Eventually this phenomenon known as post-glacial rebound will slowly turn the whole Bothnian Bay into a lake. The Upthrust Park is a collection of sites where one may get some feeling on this fancy phenomenon. Info plates.
- The South Scandinavian Ra: The Ra is the largest terminal moraine in Southern Scandinavia and Finland. The Ra was created at one of the last glacial advances around 11,000 years B.C. The Ra crosses the Scandinavian peninsula roughly between Oslo and Stockholm, then runs around Norway's south coast. Ra is an old Norse word for a ridge of gravel. Terminal moraines are typically mixed material of boulders, pebbles, sand and clay. On the surface, finer particles have been washed off and left course particles like boulders and pebbles. In Norway, the Ra is clearly visible and well-known particularly in Østfold and Vestfold areas around the Oslofjord. Some of Norway's best agricultural land is along the slopes of the Ra. In Vestfold the main road has since prehistory followed the Ra because the highest point of the Ra is naturally dry and stable. In Østfold road E6 runs along the Ra between Halden and Moss (about 60 km).
- 15 Svelvikryggen
- 16 Vandresteinen i Stavanger
Rest of Europe
[edit]- Snowdonia in Wales
North America
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Beringia
[edit]During the last ice age, what is now the Bering Sea was land and people migrated across this Bering Land Bridge from Asia into the Americas. There are a few archaeological sites from the period; see Indigenous cultures of North America.
There are parks on both sides of the straits:
Both are difficult to visit, quite remote with limited transport and a cold climate.
Flora and fauna
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2 m (6.6 ft) at the shoulder
Many species of large animal, which biologists call megafauna, that were common during the ice ages became extinct around the end of those ages, about 10,000 BCE. These included the woolly mammoth, woolly rhinoceros, saber-tooth tiger, and several species of deer and cattle (aurochs) much larger than modern species.
One site is particularly famous for preserved examples of these beasts:
See Paleontology for other sites and other museums.
Other species that were widespread then, such as reindeer in Europe and caribou in North America, survive to this day though their range has been reduced. Polar bears are another survivor, and a tourist attraction in Churchill, northern Canada.