It's a wee bit cooler today but nothing like 126,000 years ago when the #AtlanticBubble was covered in ice!
The last ice age ended 10,000 years ago but there have been glacial periods in #NovaScotia on and off for at least 500,000 years...
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During periods of climatic cooling, ice sheets develop and advance, aided by the reflection of the sun's light from the white snow surface. Sea levels drop as ocean water is used to make ice. The glaciers grow, coalesce and flow all the way out to...
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...the edge of the continental shelf. There, melting and ice sheet disintegration begin as glaciers become buoyant in deep water. This starts the retreat process, which is accentuated as the sea-level rises, and helps to further destabilize the ice sheets.
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Finally, the rising sea and global warming win out and the glaciers are in full retreat. Land, depressed by the weight of the kilometre-thick glaciers, is driven upwards as the earth rebounds.
Glaciers shaped #NovaScotia as we know it today. For example:
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Most lakes in #NovaScotia, like #LakeBanook and #BrasdOrLake, were made by glaciers carving depressions in bedrock that filled with water as glaciers melted.
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Glaciers created landmarks like #CitadelHill and George’s Island, which are drumlins - rocks, gravel, sand and clay left by glaciers as they receded. Even famous, mysterious #OakIsland is a drumlin!
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#SableIsland is the top of a huge sand bank (a "moraine") left by melting glaciers 18,000 years ago when sea levels were 100 metres lower than now. As sea levels rose, it became an island.
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The #AnnapolisValley was carved by glaciers because its soft sandstone was easily eroded. South Mountain and North Mountain resisted erosion because they are made of harder rock – South Mountain is granite and North Mountain is sandstone covered by basalt, which is very hard.
The sand, soil and clay at #CapeBreton’s #CabotsLanding are glacial outwash - sediments deposited by glaciers as they melted. Much of the sediment is eroded from the #CBHighlands, which used to be much bigger - the Highlands are a remnant of...
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...the Appalachian Mountain chain which formed 480 million years ago when North America and North Africa started colliding.
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