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Okotoks Erratic

One of these things is not like the other; one of these things does not belong. That’s what “erratics” are like. They are rocks that look out of place (they do not belong) when compared to other rocks around. This means that erratics have been transported (moved) somehow to where they are now. Weird don’t you think? Some of these erratic rocks are huge! So how do they travel long distances? Does someone carry them? The answer to the last question is No. Nobody carries them! In the mountains there are rivers of ice called glaciers. When the ice started to melt and the glacier began its retreat, the rocks, known as "erratics", were left behind in a ribbon extending from Jasper along the western prairie edge south to northern Montana, roughly the contact zone between the continental and mountain ice sheets. Of this group, known collectively as the Foothills Erratics Train, the 16-tonne (17.6 ton) piece at Okotoks, dropped at its final resting place about 12,000 years ago, is by far the largest; indeed, it is considered North America’s largest glacial erratic.

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