Canada
Geology of Canada's National Parks
Through Pictures
(at least the one's I have been to)
Visited in 2017
I had never been to a Canadian National Park and I wasn't sure exactly what to expect. I'm still not entirely sure how they compare to the US National Parks. Our first park of the trip was to Banff just west of Calgary. There is an entire town within the National Park boundaries that seems to be part of the park, unlike in the US where towns are generally not considered as part of the park, even when located within the park. I would say that overall, this is an absolutely gorgeous park that I wouldn't hesitate a moment to return to. The amount of geology within the park is truly astounding so my plan is to only hit a couple of the geological highlights along our trip, going from south to north through the park.
.jpeg)
Our first stop within the park was to the Banff Upper Hot Springs, which is a pool that uses water from the local hot springs. The water initially seeps into the ground in Mount Rundle's high western slopes, then works its way down into the ground through the sedimentary rock layers were it is slowly heated, pressurized, and enriched with local dissolved minerals (including sulphates, calcium, bicarbonate, magnesium, and sodium). After hundreds of years it then rises up towards the surface along the Sulphur Mountain Thrust Fault until it reaches the surface at one of the several outlets, including this one at the Upper Hot Springs.
.jpg)
View of Cascade Mountain from the town of Banff. Cascade Mountain is made up of Devonian and Mississippian age rocks. Banff National Park is Canada's oldest national park and the third oldest park in the world. It is known mainly for its glacial landscape which includes more than 300 glaciers, however that number is quickly shrinking as the planet quickly heats up from climate change.
Geology of Cascade Mountain. Image courtesy of the Geological Survey of Canada.
Starting at the base of the mountain (at least as far down as we can see) is the Palliser Limestone. The Palliser limestone (aka Palliser Formation) is a Late Devonian (~360 million years old) that was deposited along a warm, coastal shelf environment, very similar to the Bahama Banks today. Then above that along the more eroded slopes is the Banff Shale. The Banff Shale (aka Banff Formation) is also a Late Devonian age deposit that was deposited in a sediment rich marine environment. And the top of the mountain is capped with the resistant Rundle limestone. The Rundle Limestone (aka the Rundle Group) is a Mississippian age (~340 million year old) limestone deposited in a marine environment.
.jpeg)
Moving our way north from Banff, we stopped at the Lake Louise area. We were able to take a hike outside the visitors center and up along the Bow River. Here we have a view off to the south west looking at the Canadian Rockies. The amount of glacial features within the park is simply astounding. Glaciers are giant blocks of ice that don't melt during the summer. Over time they build up from snow that eventually gets so big that it starts to flow down the side of a mountain within the previously existing river valleys. As it flows it erodes away the ground that it is flowing over. Here you can just glimpse one of the glaciers located between the mountains as well as the harshly carved mountains typical of glacial terrains.
.jpeg)
One of the goals of the trip was to do some paddle boarding on Moraine Lake, the lake in the valley neighboring Lake Louise. Despite the heavy traffic to the lake we were able to plan to come back during the evening hours and made it up to an almost solitary part of the lake where we could spend the evening with just us. Moraine Lake is a moraine dammed lake. The valley was carved out by glaciers initially. You can tell a glacial carved valley from a stream carved valley because a stream carved valley will typically have a "V" profile from the stream constantly eroding straight down at the point of the water contact. However, since a glacier often fills most, if not all, of the valley it will erode on all sides equally creating a "U" shaped valley. Glaciers also carry the sediment that they erode out within the ice. Eventually the ice melts when it reaches an elevation or a climate that is too warm for it. At this point the glacier acts like a conveyor belt, dropping all of the sediment it had been carrying along the way into one big pile called a moraine. That is what happened here. A glacier carved out the valley and as it was melting away it deposited a pile of sediment (glacial sediment is called till) at the end of the valley forming a dam for the lake to sit behind.
.jpeg)
Glaciers also have a tendency to rub along the ground with the rocks and sediments embedded within them grinding down the rocks to a fine flour. This is called glacial flour and it is actually what gives the lake its lovely turquoise color when the light reflects off of it (suspended sediments in the water). Here is another view of Moraine Lake, facing west off into the valley.
.jpeg)
Despite the constantly warming climate which we are faced with in todays world, there are still some glaciers that are present and easily visible within the park. Moving our way a little further north the glaciers have a tendency to get a bit bigger and more noticeable. We are now traveling along the Icefields Parkway, making a at Bow Lake.
.jpeg)
There are a couple of glaciers visible at Bow Lake including this one, Crowfoot Glacier along the southwestern edge of the lake. The glaciers visible in the park have a tendency to only be a small outlet from a much larger icefield further up the mountains that generally aren't visible from the road. The glaciers along Bow Lake are all part of the Wapta Icefield to the west.
.jpeg)
Even in July, these waters are COLD. You can see Bow Glacier in the back of the photo here at the foot of Bow Lake. Bow Lake is another moraine dammed lake, like Lake Louise. The mountains seen here in the distance are made up of Cambrian quartzites and shales (~530 million years old) overlain by Middle Cambrian Limestones (~510 million years old).
.jpeg)
There are several types of river systems that are possible depending on the environment in which they are found. Within this region you get a lot of braided rivers. The North Saskatchewan River is a prime example of this type of river system. A braided river is where at times the river has a ton of water and energy, specifically around the spring melt. This enables the river to transport large amounts of sediment, but only during this time. At other times of the year the amount of water isn't enough to transport all the sediment in the river, causing it to dump the sediment as the water levels decrease to a trickle of what they once were. What is left is a series of river channels that weave in and out of each other within the river bed around the piles of dropped sediment, like a braid.
.jpeg)
At the northern most limits of Banff National Park along the Icefields Parkway the road takes a sharp, hairpin turn that at that top of gives a fantastic view off to the south. Here you can look down the North Saskatchewan River valley and you can see the beautiful "U" shaped glacial valley right in the center with the smooth sweeping valley walls characteristic of glacial terrains.
References
https://www.pc.gc.ca/en/voyage-travel/promotion/sources-springs/banff/debit-flow
https://graciesliu.github.io/iffall2017/microsite/www/geology.html
https://doi.org/10.1306/5CEAE45D-16BB-11D7-8645000102C1865D
http://parkscanadahistory.com/geology/misc-report-1-1960.pdf
Visited in 2017
Continuing our trip north from Banff National Park, we hit the southernmost feature of Jasper National Park. Just after crossing the park boundary along the Icefields Parkway you come to the Icefield Centre where you can park and walk practically up to an active glacier, called Athabasca Glacier. There are also tours available where they take special vehicles onto the glacier, but we opted just for the hike to the base of glacier.
.jpeg)
Although not currently visible from the parking lot, the Athabasca Glacier at one time reached far beyond where I am currently standing. The glacier is part of the Columbia Icefield which spreads for a total of 150 square miles across both Banff and Jasper National Parks as well as neighboring Hamber Provincial Park.
.jpeg)
Glaciers are very sensitive indicators of climate change, whether to a colder climate or a warmer one. If the climate is consistent the glacier will balanced, where the amount of melting is equal to the amount of accumulation of snow and ice. For a consistent climate the glacier will not change in size but slowly act like a conveyor belt carrying the rocks and debris it picks up towards the melting end of a glacier. At the toe of the glacier all of that debris (called till) is deposited into a pile called a moraine. If the climate is cooling, then the amount of snow and ice accumulation would be greater than the amount of melting and the glacier would grow. It will continue to grow until the end of the glacier reaches a warm enough temperature where the amount of melting will match the amount of accumulation. If the climate is warming, the opposite will take place with the amount of melting exceeding the amount of accumulation. The glacier with then shrink until either it finds a new balance point or completely melts away.
With the current climate change crisis, the climate is warming at an incredible speed and the glaciers are recording this event, to their detriment. Many stewards for the glaciers across the globe, especially the more accessible ones, have been putting up signs to indicate how quickly the current glaciers are slowly sliding away. Unfortunately for Athabasca Glacier these signs had more often than not been destroyed by visitors but at least this one for 1982 still existed when we had visited in July of 2017. The first picture above represents where the glacier was in ~1977.
.jpeg)
Upon coming over the hill of rock we are finally able to see the glacier. Where I am standing is approximately the place that the glacier extended to ~1992, and is the one of the closest spots I could get to the glacier from this direction. Up on the top of the glacier you can see the edge of the Columbia Icefield as the snow falls over the edge into the Athabasca Glacier at the top of the valley. You can actively see the glacial meltwater coming off the glacier and forming a river that flows down into the valley.
.jpeg)
When glaciers travel over the ground the bottom ice of the glacier is constantly freezing and thawing. In the process rocks, sands, powdered rock, and other things all get trapped in the ice. Then as the glacier slowly slides forward, all of the debris on the base of the glacier is dragged across the soil and rocks that are there. Eventually anything that can easily be moved is eroded away and all that is left is bedrock, which the rocks are then dragged across as well. This produces scratches across the rocks known as glacial striations, as seen here. If the glacier was no longer around, scientists can still use the striations to identify if there was a glacier there at one point in time and the direction that the glacier traveled by using these lines as a compass. As seen here, all of the lines point straight back to the glacier.
References
http://parkscanadahistory.com/geology/misc-report-6-1963.pdf