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Coastlines of the Ice Age

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This map shows how the coastlines of the world may have appeared during the Last Glacial Maximum, around 21,000 years ago, when sea levels were approximately 125 meters (410 feet) below present. This map doesn't include any of the large paleolakes of the time period, it's intended to mainly just show extra land and the different coastlines.

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© 2017 - 2021 atlas-v7x
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That Hawaiian island chain...

Jdailey1991's avatar
Hold on--why are the Inside Passage and the Great Lakes of the West covered in ice?
atlas-v7x's avatar
This show the ice sheets coverage at its greatest extent. This is basically how the great lakes were formed. During the ice age, most of North America was covered in this thick sheet of ice, similar to what exists today on Antarctica and Greenland,with Greenland's ice sheet being what remains today of the once much larger ice sheet. In some places this ice sheet was up to 3 or 4km thick. It flattened and carved out a large portion of North America, including the basins of the great lakes, and as the ice sheet receded, its meltwater filled these basins creating these large lakes. This is the reason Canada has so many lakes, as with Scandinavia.
Jdailey1991's avatar
But evidence in places like Admiralty and Prince of Wales islands show that the Inside Passage was never covered in ice.
atlas-v7x's avatar
I'm not sure, that's just that data I found. I take it you might have actually been referring to the lakes such as Bonneville and Lahontan and not the Great Lakes, perhaps assuming the data is correct, these areas were at the time covered in ice, and may have been the source of the lake water when that ice later melted.
Jdailey1991's avatar
Bonneville and Lahontan evaporated when the ice melted.  Find a map of the Great Lakes of the West in :iconLaTierna:'s profile.  Those lakes existed because the ice created a high-pressure area that pushed the jet stream southward.
Thomas-Rey's avatar
Thanks a lot for this !
Thomas-Rey's avatar
A little nitpick, I'm wondering if there's a problem with the Mediterranean and the Black Sea. I seem to remember they were at a lower level at the time showing different coasts.
atlas-v7x's avatar
The Mediterranean was the same sea level as the rest of the ocean at -125m which is shown here. The Black Sea was in fact higher than present day, as rivers such as the Ob River of Russia which drains north towards the Kara Sea of the Arctic, were blocked off by the ice sheets. This ice dam created a large lake which flowed all the way back raising the levels of the Aral Sea, the Caspian Sea, and the Black Sea. Here's a map I made which shows how that might have looked
Thomas-Rey's avatar
Thanks for these infos ;)
atlas-v7x's avatar
I did some reading about this, and I think you were right about the Black Sea being lower at Glacial Maximum. It seems this flooding would have happened just after the maximum, not during, but I'm still confused about the exact time period since surely the flooding would have had to have happened while there was still an ice dam in the north.
Thomas-Rey's avatar
I read that the Gibraltar strait was blocked by rocks at the time and so were the Dardanelles/Bosphorus. Some archeologist even think that the biblical flood is a story based on the flooding of the Black Sea and that climate refugees fleeing south brought the story to babylon. The hebrews might have write the Old Testament during their exile here.

I'm not aware that there is a single event that can be attributed to the flood story. There is every probability there are a series of floods to account for the recollection the world over as well as the Middle East. The Arabian sea it self is believed to have been cultivated land which his map allows for.


It should be kept in mind that the planet with so much water ice would have been a considerably drier place. I haven't seen a model for what the Mediterranean, North Africa and Middle East would have been. There is so much unstudied evidence coming to light that gaining a clear picture on how this tumultuous heart land spun the future prospects of the people living there.

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