I recently read the Wandering Canadian‘s hiking report where they came upon some drumlins in Ontario. As a huge ice sheet once covered all of Canada, it was interesting to know that these ancient remnants of glaciers are still visible.
Since then, I have found myself admiring our own local drumlins. When I showed them to a few hiking friends, I realized no one had heard of a drumlin, much less knew where to find them. I think I missed my calling as a geologist, because I find everything to do with our Rockies absolutely fascinating.
What is a Drumlin?
A drumlin is a remnant of our glaciated ice age history. It is a small, teardrop shaped hill made of glacial till. As glaciers move, grow and shrink, they churn up the rock beneath these massive sheets of ice, creating glacial till.
You might be thinking that a drumlin sounds a lot like a moraine. They are both made from the same material, but form in drastically different ways. A moraine is pushed into place by the edge of a glacier, while a drumlin is formed beneath an ice sheet.
When an ice sheet melts, it does so from above and below the ice. The below ice melting forms an under-ice river. Just like silt deposits in a regular river, the under-ice rivers would also deposit glacial till, made up of silt, sand and pulverized rock. As these deposits built up, the under-ice river would start to flow around the deposited glacial till. This is how the tear-drop shape is formed, with the blunt steep end being the start of the drumlin, and the tapered, gently sloping end being the tail end.
Where are Drumlins Found?
In Canada, drumlins were formed at two different times. The drumlins found in northern Saskatchewan heading east to Quebec were formed beneath the Laurentide Ice Sheet. The Alberta drumlins were formed during the most recent glacier period, called the Wisconsin Glaciation.
In Alberta, we see drumlins every time we drive from Calgary into the mountains. They are so close, you can reach out and touch them. Many people do touch them when they stop to make words using the stones jumbled up in the glacial till.
Drumlins are found in Morley flats, and around the Ghost Reservoir. They run in the same direction as the path of the glacier.
Here is an overhead view of the Morley flats drumlins.
This is a close up overhead view of one drumlin found alongside the Trans-Canada highway.
This is a sideview of a drumlin.
Here is a view of a small ‘swarm’ of drumlins.
Here is a close-up of the front of a drumlin.
This is the tail end of the same drumlin.
Why is it called a Drumlin?
According to wikipedia, drumlin is an Irish word meaning littlest ridge. Ireland isn’t the first place I think of as covered in an ice sheet, but it must have because the drumlins of Clew Bay are somewhat famous. This is a great view of the Irish drumlins courtesy of The Geological Society.
I hope you enjoyed learning about drumlins, and discovering that they not only live among us, but that you have been driving right past them on your trek to the mountains.