Let me start with a clarification of scientific terms: What is commonly referred to as the “last ice age” should more accurately be called the “last glacial period” within the current ice age. Yes, you’ve read correctly. Since the earth's poles are still covered with ice, from a scientifical viewpoint, we are still in an ice age, however in an interglacial period. Planet earth has, according to present days knowledge, experienced six major ice ages. Throughout the current ice age, the global ice shields advanced and retreated several times, which are respectively classified as glacial and interglacial periods.
The last glacial period began around 115 000 years ago and ended about 10 000 years ago with the entrance into the current Holocene epoch.
Sweden under ice
For a period of around 100 000 years, Sweden as well as the rest of Scandinavia was covered under a thick layer of ice. In central Sweden, where todays’ county Sörmland (Södermanland) is located, the ice shield reached up to 2 000 meters in thickness. Such a body of ice imposes a huge weight on the land masses beneath. The Scandinavian subcontinent was therefore pushed down into the viscous earth mantle.
With the ice’s regression starting about 18 000 years ago, the land masses began to bounce back like a cork pressed under water and released; way slower of course. The Swedish coastline has therefore not only changed due to the global (eustatic) sea level rise of about 125 meters after the meltdown of the vast ice shields, but as well due to the post-glacial rebound of the land masses themselves, the so-called isostatic change.
This means that Sweden's surface is still growing - peacefully and without conquests!
In today’s landscape the traces of the last glacial period can be found everywhere. Briefly, they can be categorized in glacial and fluvioglacial landforms. While glacial forms were directly created by the influence of ice, fluvioglacial forms were shaped through meltwater by the end of the last glacial period. One may not forget that a 2000-meter-thick body of ice takes a couple of thousands of years to melt down, transforming into massive streams of water. Their force may not be underestimated.
Commonly found landforms are
· Giant’s kettles
· Kettle holes
· Pebble stone fields indicating former coastlines
Explaining each form in detail would go too far at this point. However, I will dedicate further articles to the exploration and characterization of both glacial and fluvioglacial forms with their respective examples found in Sörmland’s landscape.
- How did the ice age end?: https://www.amnh.org/explore/ology/earth/ask-a-scientist-about-our-environment/how-did-the-ice-age-end
- Sveriges geologiska undersökning: https://www.sgu.se/om-geologi/jord/fran-istid-till-nutid/
- The Conversation: https://theconversation.com/climate-explained-what-is-an-ice-age-and-how-often-do-they-happen-166652
- Glacial and interglacial periods EnergyEducation: https://energyeducation.ca/encyclopedia/Glacial_and_interglacial_periods
- Geographyas: https://geographyas.info/coasts/sea-level-change/
- Letzte Kalktzeit Wikipedia: https://de.wikipedia.org/wiki/Letzte_Kaltzeit
- CoolGeography: https://www.coolgeography.co.uk/A-level/AQA/Year 12/Cold environs/Fluvioglacial/Fluvioglacial landforms.htm
- Holocene EnergyEducation: https://energyeducation.ca/encyclopedia/Holocene
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