Bing Banff Boom

A Brief Forward

There are many ways a person can benefit from the experience of travel. Perhaps one of the more unexpected benefits is developing an ability to be flexible because sometimes, no matter how carefully planned a trip might be, circumstances arise that necessitate change. When they do, I’ve found the best course for me is to quickly release my frustration, maximize my flexibility and find an alternative.

My experience at the auto rental counter in Calgary which, at times, felt tangentially related to a Seinfeld episode not only presented the opportunity for me to display some equanimity but was also portentous in regard to the next few weeks – though I didn’t know it at the time. It began with what seemed to me a rather cumbersome process to simply pick up the car.

I waited in line to reach the desk where I confirmed my reservation. After providing reams more information, enduring the pitches to purchase this, that or some other type of additional insurance I learned that the company imposed a $10 per day surcharge for taking the car out of the province of Alberta. This was followed by the attempt to up sell me to a larger car. I declined and told the agent that I wanted the smallest car available.

For the next step in the process I was instructed to take a seat across the lobby and wait for my name to be called at which time they would provide the keys, have me sign additional paperwork and direct me where to find the car. Budget needed nearly 20 minutes to complete this step. When the agent called my name, she told me they had upgraded me to a full sized car but would do so at no additional charge. She was not only shocked when I insisted that I wanted the compact car I’d reserved, but told me that she didn’t know if they had a compact car available. (It seems they could take the reservation but not hold the reservation.) I told the agent that I’d find a sub-compact more acceptable than a larger car.

Another 20 minutes passed before they managed to scrounge up Honda Civic – one I assumed had been very recently returned because it hadn’t been vacuumed or washed. The agent did waive all by two days of the out of province surcharge and by this time, I was hungry and had spent more than an hour and a half longer in the airport than I’d anticipated so I made no attempt to negotiate the waiver of the final two days. However, the delay also meant I’d have to skip stopping at some of the places between the airport and the park that I wanted to visit.

Although the primary focus on this trip will be the time I spend in Wyoming and Montana, I started in Canada’s Banff National Park nestled in the Canadian Rocky Mountains which have their northern terminus at the Laird River in the northeastern corner of the Yukon Territory and end at the U.S. border in the south. As for my route in Canada, it looked generally like this (though I’d use AB2 on my return to Calgary):

 If you enlarge the map, you can complete my Alberta circle by looking directly west of Sweet Grass and finding Carway. Then follow AB2 north toward Calgary. This is the route I drove when I left Glacier National Park.

The American Rockies span parts of Idaho, Montana, Wyoming, Colorado and even dip into northern New Mexico. So, while none of the mountains I visited in my recent trip to Arizona and Utah are part of the Rocky Mountains, all of the mountains on this trip will be. Since it’s a two and a half hour drive to to reach the Moraine Lake Lodge where I’m staying in Banff, we have lots of time to study the Rockies.

The full expanse of the Rockies includes many subranges and the Rockies themselves are part of the North American Cordillera. (A cordillera is a chain of geologically related mountain ranges.) The North American Cordillera stretches from the Southern Alaska Range which includes Denali, the highest peak on the continent to the three Sierra Madre ranges in Mexico. Along the way, we’ll see that these mountain ranges have a complex structure in this case as a result of folding and faulting accompanied by volcanic activity.

ROCKY MOUNTAINS

How did the Rockies earn their name?

For those of you who have been to the Rockies or seen photos the answer to this question might seem self-evident but objectively, it’s difficult to discern any observable difference between the mountains of this range from many other mountain ranges in the American west. In fact, 18th century Spanish explorers and soldiers coming from the south referred to sections of the Rockies as La Sierra de la Grulla (Mountains of the Cranes) and La Sierra del Amagre (Mountains of Red Earth).

Coming from the east, as evidenced by a 1730 map, the earliest French explorers called them les Montaignes de Pierres Brilliantes or mountains of bright stones. The general English translation was the Shining Mountains.

However, according to the book “Mountain Names” by Robert Hixson Julyan, French trappers and traders, accustomed to “rounded, forest-clad mountains” in the East translated the Cree phrase as-sin-wati meaning “when seen from across the prairies, they looked like a rocky mass” into les Montaignes Rocheuse. This then translates into English as Rocky or Stony Mountains and, while Thomas Jefferson used the latter term, other European-Americans coming from the east generally used the former. And now you know the rest of the story.

So, you want to make a mountain

In reporting my wandering through Arizona and Utah several weeks ago, I focused a considerable amount of my geological discussion on the process of uplift because it was so important to the formation of so many of the canyons I visited. Uplift, or more specifically isostatic uplift, is one of the tectonic forces that create mountains. The tectonic partners of isostatic uplift are intrusion of igneous matter and compressional forces. In its own way, each of these processes, known collectively as orogeny, force surface rock upward creating a land form significantly higher than the surrounding features that we call a mountain and of which there are three main types – block (sometimes called fault-block), volcanic and fold.

Block mountains

Because it passes through or near some of the country’s most densely populated areas, most Americans likely have at least a passing familiarity with California’s San Andreas Fault. The San Andreas Fault is the tectonic boundary between the Pacific and North American tectonic plates. (A tectonic plate is a sub-layer of the earth’s crust -also called the lithosphere – that moves, floats, and sometimes fractures.) When tectonic plates interact, the result contributes to any or all of the following: continental drift, earthquakes, volcanoes, mountains, or oceanic trenches.

When these faults move against one another, the rocks on one side of a fault rise relative to the other in the process known as uplift or rifting. The uplifted blocks become block mountains (also known as horsts) while the intervening dropped blocks are known as graben (i.e. depressed regions). These block mountains break up into chunks and move up or down. Fault-block mountains usually have a steep front side and then a sloping back side. It is just this sort of interaction that gave rise to California’s Sierra Nevada Mountains and that one can see in Mount Rundle

looming over the town of Banff.

Fold Mountains

So, when two plates rub against one another at a fault line they create block mountains. When they meet in a head on collision, they create fold mountains. As they collide, the edges of each tectonic plate crumple and buckle forcing the less dense crust to float on top of the denser mantle rocks. The material being forced upward forms hills, plateaus and, over time, mountains. This is the most common mountain building process on earth and is the process that built not only the Rocky Mountains but the Appalachians, Himalayas, Alps, Andes and others. (There are some problematic issues concerning the Rockies – especially in the U.S. but I’ll delve into those at another time.)

Volcanic mountains

Everybody and everything likes being cool. When people get hot, they sweat to release that heat and get cool. When dogs get hot, they pant (and slobber a bit). To cool itself, the Earth pushes its hot magma toward its surface. As it rises, gas in the magma forms bubbles that create intense pressure forcing the surface rock upward. If the source remains in place, eventually something’s got to give and the magma erupts as lava, ash, rock and volcanic gases. When this material builds up around the volcanic vent, it creates a volcanic mountain. Japan’s Mount Fuji and Mauna Kea in Hawai’i are two of the planet’s more iconic volcanic mountains.

There’s another type of volcanic mountain called a dome mountain. Sometimes, magma can push its way toward the earth’s surface but before it finds an outlet and erupts, the source of the magma disappears and the pushed up molten rock cools and hardens into a dome like shape. Mount St. Helens in Washington is an example of a dome mountain.

Go Tell What Kind of Mountain

Regardless of the process that formed them, not all mountains look alike. So, within the broad formative categories described above, geologists have a range of more specific terms to describe different types of mountains. The Canadian Rockies consist of several southeast-northwest trending ranges and two of them – the Main Ranges and the Front Ranges – are found in Banff. Several subranges comprise the two principal Banff ranges.

Traveling from north to south, the Main Ranges, which form the western border of Banff National Park and mark the Continental Divide, include the Waputik, Bow and Blue Subranges. (Rivers west of the Continental Divide empty into the Pacific Ocean while those on the east empty into the Atlantic.) The high peaks west of Lake Louise are part of the Bow Range. The eastern border of the park and the town of Banff includes all of the Front Ranges the Sundance, Palliser and Sawback subranges from south to north. Now, even though I probably couldn’t tell one from the other (which is why I will use photos from other websites), perhaps you can so let’s take a look at the different types of mountains.

Anticlinal Mountains

Those of you who read about my visit to Arches National Park have already encountered the term anticline. When rocks are compressed, they don’t always crack. Sometimes they are compressed into smooth domes (anticlines) or depressions (synclines). These structures can be preserved in the mountain form to create anticlinal mountains. Moose Mountain which was south of my route from Calgary to Banff in the foothills, is an anticlinal mountain. I found this picture of Moose Mountain from the Explore Calgary Pinterest page.

Castellate

Named for their vertical towers and step-like character reminiscent of ancient castles castellate mountains are distinguished by horizontal-lying layers that are typical of main range peaks. Castle Mountain west of Johnston Canyon (more about that in a later post) is a textbook example of a castellate mountain.

Dogtooth Mountains

When you see mountains with jagged peaks that jut straight up into the sky seeming to defy the elements, you’re looking at dogtooth mountains. Theses form when masses of almost vertical layers are eroded but layers of very hard rock remain as an erosional remnant. In Banff National Park, Mount Louis, seen below in a photo taken from REI’s Mountain Project Page, is a classic example of a dogtooth mountain.

Matterhorn Mountains

When glaciers scour four different sides of a peak, they may create a square-topped summit similar to the Matterhorn of Europe which has given its name to this mountain type. Mount Assiniboine, which borders the Banff-Mount Assiniboine Provincial Park, is the tallest mountain in the park and is the most photographed example in the Canadian Rockies. (Officially, Mount Forbes at 3,612 meters is the tallest mountain entirely within Banff National Park. Mount Assiniboine, which straddles the two parks, soars a full six meters higher than Mount Forbes.) Here’s Mount Forbes as shown on the website Explor8tion.com.

Sawtooth Mountains

Sometimes a long ridge of mountains is composed of almost vertical layers of rock. When these layers are eroded into a jagged ridge resembling the blade of a saw they are described as sawtooth mountains. In Banff, the Sawback Range exhibits classic sawtooth form and I hope you can see it in this photo from Phil Howland’s Panoramio page.

Synclinal Mountains

The converse of anticlinal mountains are  mountains formed in dipping troughs and are known as synclinal mountains. A syncline is a fold where the younger layers of rock are closer to the center of the structure. In Banff National Park, Cirrus Mountain exemplifies this type of mountain. Anticlinal and synclinal mountains both belong to the larger category of fold mountains.

 This photo came from Summit Search Mountain Community.

There are two additional mountain types in Banff NP that are more difficult to categorize.

Mountains cut in dipping-layered rocks

Some mountains result from horizontal layers of rocks being thrust up at an angle of 50-60º. This results in a peak with one sweeping, smooth face and one sharp, steep face where the edge of the uplifted layers are exposed. Mount Rundle, which overlooks Vermillion Lakes and was called Waskahigan Watchi or house mountain by the Cree First Peoples is this type of summit.

Complex Mountains

Finally, some mountains simply defy classification. They may have a combination of upfolds and downfolds resulting in very complex structures. These are the typical mountain forms in the eastern portions of Banff NP.

What Kind of Rocks make up the Canadian Rockies?

Now that we have an idea of what kind of mountains form the Rockies, it seems reasonable to ask what kind of rocks comprise them and, since I’m starting the trip in Canada, the logical place to start the answer is in the Canadian Rockies.

The Rockies rose up during a period known as the Laramide Orogeny which began in the late Cretaceous period, 70 to 80 million years ago, and ended in the Tertiary some 35 to 55 million years ago. (Orogeny is the process that laterally folds and deforms the earth’s crust and compresses it to form mountains.) Fortunately, the process involved in raising the Canadian Rockies is less of a puzzle than the one that that gave rise to the U.S. range of the same name and which involves an overlapping orogen called the Sevier Orogeny.

Thirty to fifty million years prior to the start of the Laramide Orogeny, in the mid-Cretaceous, much of what is now North America was covered by a huge inland sea called the Western Interior Seaway. Throughout most of its existence the sea was relatively shallow with an average depth of 183 meters. In what is known as a flat slab subduction, the Farallon tectonic plate pushed against the North American plate opening relatively shallow depressions that allowed the waters of the Arctic Ocean and Gulf of Mexico to mix. (Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is either forced down or sinks due to gravity into the mantle. Regions where this process occurs are known as subduction zones.)

Over tens of millions of years, the sea regularly grew and receded. As you might recall from some of the geology in my Arizona – Utah journal, when seas recede they leave sediment behind. Thus, as you might suspect, the Canadian Rockies are composed of different types of sedimentary rock and the most common types you’ll find are shale, sandstone, dolomite and limestone.

Because I’ve noted that the Rocky Mountains rose up during the Laramide Orogeny,

you might reasonably expect that the exposed rocks would be mostly from that period. That’s not quite the case. That’s due to a pre-existing land form known as the Laurentian Plateau.

Sometimes called the Canadian Shield, the Laurentian Plateau, is a large area of Precambrian igneous rock that once formed the geologic core of Laurentia – the supercontinent that eventually became North America. A tectonic plate called the Kula plate subducted against the North American plate as part of the process that raised the Rockies. However, as the subduction of the Kula plate pushed toward the east, it met considerable resistance from the Laurentian Plateau and exposed much older rocks. Some of the rocks, particularly those on the east side of Banff, are as old as 600 million years and date from the Precambrian. Others are as young as the lower Cretaceous (145–66 m.y.a.).

How did this happen? Picture the expanding and collapsing seating area in a gymnasium. The hardwood floor underneath the seats would be the Laurentian Plateau and the seating area would be the ancestral rocks. After a game, the crew pushes against the seats causing them to fold in on each other. In the case of the Canadian Rockies, the crew would be the subduction of the Kula plate smashing into the rocks. As the seats fold in, they rise ever higher. This process ended in the Canadian Rockies about 55 million years ago. The main difference would be that in a geologic process the plateau would also experience some folding while the floor underneath the does not.

Rubbing mountains the right way

As the Laramide Orogeny ended, it’s likely that height of the Canadian Rockies was in the range of 8,000 meters – comparable to today’s Himalayas. But once the mountain formation process ceased, erosion was free to move in as the dominant force in shaping the mountains.

Over the past 80 million years, erosion has taken its toll on the landscape, with more extensive erosion occurring in the foothills and Front Range than in the Main Range. Early in the process, water was the principal erosive force.

We’ve seen that Banff’s mountains exhibit several different shapes. These have been influenced by the composition of rock deposits, layers, and their structure. Numerous mountains in Banff are carved out of sedimentary layers that slope at 50–60 degree angles. Such dip slope mountains have one side with a steep face, and the other with a more gradual slope that follows the layering of the rock formations, such as the example of Mount Rundle, near the town of Banff.

As noted above, the mountain formations in Banff include complex, irregular, anticlinal, synclinal, castellate, dogtooth, and sawback mountains. Castle Mountain exemplifies a castellate shape, with steep slopes and cliffs. The top section of Castle Mountain is composed of a layer of Paleozoic-era shale, sandwiched between two limestone layers. Dogtooth mountains, such as Mount Louis, exhibit sharp, jagged slopes. The Sawback Range, which consists of dipping sedimentary layers, has been eroded by cross gullies. Scree deposits are common toward the bottom of many mountains and cliffs.

More recently, beginning with the Quaternary glaciation two and a half million years ago, glacier ice carved many of the mountains into their present shapes. In fact, glacial landforms dominate Banff’s geomorphology. Those in the know can see all the classic glacial forms including cirques, arêtes, hanging valleys, moraines, and U-shaped valleys. The pre-existing structure left over from mountain-building strongly guided glacial erosion and this combination accounts for the many varied mountains types seen in Banff National Park today.

Glaciers are the largest ­moving objects on earth. They’re massive rivers of ice that form in areas where more snow falls each winter than melts each summer. Their scale can be truly gargantuan — the glaciers that form the ice cap covering Greenland hold enough ice to submerge the whole of planet Earth under 17 feet of water. The glaciers of Antarctica are so heavy they actually change the shape of the planet.

As glaciers advance and retreat, they can grind down mountains, scatter strange rock formations across the countryside and reduce solid rock to fine dust. In this process they can leave behind debris of rock and ice called terminal moraine. When this debris dams a river, it creates a lake behind it. Lake Louise in Banff NP is this type of glacial lake.

Somewhat ironically, while it is also a glacial lake, Moraine Lake, despite its name, was created differently. It wasn’t formed by damming of melt water by terminal moraine as is the case of Lake Louise; instead this lake was formed by damming of water run-off from the surrounding mountains by falling rocks. Moraine Lake, where I’ll spend the night, is in the Valley of the Ten Peaks.

At the time the lake crests, generally in June, the intense blue for which it and many of the lakes in Banff NP are famous generally peaks as well. When I was there in August, it looked like this:

 The sharp eyed among you might recognize this lake (and the less sharp eyed simply need to look to the right).

The photo was taken from the Rock Pile and my hotel is to the right a bit outside the frame as you can see on the map below.

As glaciers erode bedrock, they can deposit silt size rock particles known as rock flour. When these sediments enter a river, they turn the river’s color grey, light brown, iridescent blue-green, or milky white. When the river flows into a glacial lake such as Moraine Lake and Lake Louise in Banff NP, rock flour creates shades of turquoise. As the increase in water flow from the glacier during snow melts and heavy rain periods increases the extent of the river’s flow, distinct layers of a different colors flow into the lake eventually dissipating and settling to give the lake its distinctive hue.

While there’s more to see and learn, my next entry including a visit to the towns of Banff (inside the park) where I stopped on Sunday and Canmore (just outside the park) where I had lunch on Monday and visits to Johnston Canyon and Cave and Basin is more personal and much less technical.

Some final notes

Because of my upcoming trip to Spain and some extended preparations for a trip to France in April 2018, I won’t adhere to a regular publication schedule. So, those of you on my email list can check there, those who follow me on Twitter can watch that site, or simply check the main page from time to time.

And, for those who are curious about the header for this entry, it was inspired (with no particular relationship to the contents) by this song:

 

 

This entry was posted in Western U.S. and Canada August and September 2017. Bookmark the permalink.

2 Responses to Bing Banff Boom

  1. Pat says:

    So hard to read this on a cell phone after you’ve been traveling all day, then had a three-course meal + included alcoholic beverage.
    PS if your Spanish students are into geology, you are golden.

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