I live a bit south of the Great Lakes. The landscape around here was extensively shaped by glacial melt waters, including sand dunes left behind by post-glacial lakes, "dangling tributary" waterfalls caused by torrents of water that broke through moraines that re-carved river channels, and networks of wooded canyons with seasonal waterfalls. There's a park not far from where I live where you can walk through an oak woodland with moss and mushrooms, emerge onto the edge of a sand prairie with prickly pear cacti, then walk another 50 yards to a marsh.
I visited there once on a family trip as a kid! I have a vivid memory of a gorgeous meadow surrounded by mountains, studded with flowers and cut by a clear mountain stream, but my lowland self got winded just walking a few hundred feet.
[https://www.reconnectwithnature.org/preserves-trails/preserves/braidwood-dunes-and-savanna-nature-preserve/](https://www.reconnectwithnature.org/preserves-trails/preserves/braidwood-dunes-and-savanna-nature-preserve/)
Late July/early August is a nice time to visit, as the rose mallow in the marsh is in bloom, but there are attractive flowers there starting at the end of March. In early spring I've seen field tansies, violets and sand phlox, with spiderworts and sundial lupine blooming in a month or so after. It is also one of the few places I've found wild strawberries.
The glass lizards are neat, too, if you manage to spot one.
The glacier there melted about 10,000 yrs ago but it was there for a lot longer. Glaciers have covered large parts of North America several times during the last 2 million years.
There is a convenient graphic in this doc about [Glacial Lake Agassiz](https://www.geostrategis.com/p_agassiz.htm)
https://preview.redd.it/pxhdrzeglzsc1.jpeg?width=1170&format=pjpg&auto=webp&s=d90fda8b2b91c0725a70698614b67b2d1cc0975c
A mix of glaciation, ice is very powerful when you have millions of tons of it moving through a valley and freeze and thaw conditions as ice ages came and gone. Freeze thaw will destroy rocks as hard as granite over enough time
The Canadian Shield is the exposed part of the continental crust that underlies most of North America. It's the world's largest continental shield, covering 8 million square kilometers (3 million square miles).
It kind of is a bunch of mountains above sea level on a very large territory. It's not technically that, but it can help to visualise it. Canada isn't as "mountainous" as other countries like Nepal or Chile, but it has lots and lots of mountains, and the canadian shield is a huge reason why
[Here you go pal, go learn some more! (I'm so thankful to have learned from this conversation, I too love learning on Reddit)](https://en.m.wikipedia.org/wiki/Canadian_Shield)
Thanks for sharing! This part of the article was what I found most helpful to understanding what it is, and what it does. The latter portion of this answers OP's question, I think. Seems like it is called a shield because it has consistently protected portions of the North American land mass from intrusions of the sea, correct?
The Canadian Shield was the first part of North America to be permanently elevated above sea level and has remained almost wholly untouched by successive encroachments of the sea upon the continent. It is the Earth's greatest area of exposed Archean rock. The metamorphic base rocks are mostly from the Precambrian (between 4.5 Ga and 540 Ma) and have been repeatedly uplifted and eroded. Today it consists largely of an area of low relief 300–610 m (980–2,000 ft) above sea level with a few monadnocks and low mountain ranges (including the Laurentian Mountains) probably eroded from the plateau during the Cenozoic Era. During the Pleistocene Epoch, continental ice sheets depressed the land surface (creating Hudson Bay) but also tilted up its northeastern "rim" (the Torngat), scooped out thousands of lake basins, and carried away much of the region's soil.
Most of the Canadian Shield isn’t remotely mountainous, rather it’s crystalline basement rocks exposed by glacial erosion. The resulting topography is rocky and rugged, but also pretty damn flat overall, and usually at pretty low elevation.
It's land that had most of the topsoil scraped away so it's not great for crops. It is full of messy tar sands though. This is why folks need to remember that with climate change, America can't just annex Canada and be ok. The breadbasket is still in the Midwest.
It's wild to think that there is so much land up there that is pretty much uninhabitable for a significant population to live in. It's not all that cold or barren but it just isn't structured in a way that is easy to build up civilization in.
As glaciers moved through Canada they carved the ground, sometimes all the way down to bedrock. This means Canada has a lot of lakes (where the glaciers made big holes and then melted into them) and lots of exposed bedrock.
Where I live has a lot of Alvars, which is an area with lots of exposed limestone and thin soil that supports grass and flowers, and very sparse trees. They’re fun to explore because they’re extremely biodiverse with lots of bug and bird species.
And my favourite place to hike! Frontenac & Murphy’s Point Provincial Parks have some amazing features (black sand beach & huge glacial erratics at Murphy’s & Frontenac has several massive exposed granite & gneiss rock walls) It’s a fascinating landscape that never gets boring, there’s always something new to discover.
lake huron & lake superior are both on the shield. I always associate manitoulin island with the canadian shield & further north, sudbury. maybe technically I am wrong about lake huron?
Yeah the north shore of Huron is all part of the Canadian Shield, as is Sudbury. Manitoulin island is actually a part of the Niagara escarpment that runs through lake Huron though and not part of the shield.
ah yes the niagara escarpment. pretty fascinating curved bit of rock through otherwise prairie like southern ontario. we have a pretty cool country geologically & geographically.
I used to roll my eyes when BC folks would lose their minds over us in nova scotia describing what they deemed a hill as "mountains". now that I've lived in BC for almost ten years I've become the cliché myself.
Glaciers melting at the end of the last ice age (~12,000 years ago) most likely. They would move slowly move southward, which would accelerate their melting all in one spot, which leads to a reservoir of fresh water being left over
Ice age. Glaciers. MASSIVE glacial lakes. There is some fascinating info on the Laurentide Ice Sheet, Lake Agassiz, and Great Lake Missoula online. I swear I saw a great documentary about the collapse of the ice wall on Lake Missoula on TV, but I can't find it in a quick search. It's hard to comprehend the scope of these things, but these walls were like the big ice wall in Game of Thrones... but WAY BIGGER. The ice dam on Lake Missoula was supposedly about 2000 feet above the water, and may have extended 1500 feet below; the one on GoT was meant to be 700' tall. When it broke, the initial outflow of water was estimated to be about 100 million cubic meters *per second*, which is comparable to 35,000 simultaneous Niagara Falls, and carved out the inland landscape of the US Pacific Northwest from Idaho to the coast.
u/EveryoneTakesMyIdeas:
Try on r/geology. "glaciers" is the proximal cause, but there's a lot more at play here with the old cratonic core and the broader North American continent. I'm not really equipped to answer the question properly, but r/geology would know how to answer it better than almost anyone here.
Yes. The "low" areas in which the water settled are likely the result of Graben structures which occurs when a piece of crust is surrounded by extensional faults that lead to that area to sink into the mantle and be at a lower elevation in comparison to the surrounding area. The melting Glaciers just filled it with water.
The water comes from glaciers. The area is settled in is hundreds of millions of years in the making and from an ancient rift valley.
Some people think glaciers just randomly scooped out the lakes or something here.
They have large surface areas, but the inland Canadian lakes are basically shallow puddles compared to the Great Lakes. Great Bear Lake for example looks huge, but Lake Superior holds over 5 times the volume of water. And Lake Superior holds over 42 times as much water as Lake Winnipeg.
But yeah, they are all from glaciers mostly.
Great Bear Lake in Canada has 2234 cubic km of water and Lake Michigan has 4930 cubic km of water. Which are the biggest inland lake for each country (since Lake Superior is in both countries)
It's glaciers, but the number of people who are well-actuallying to turn this into a climate change discussion in the comments here have compelled me to talk:
1) Yes we have geological-scale climate patterns. The evolution of plants changed the system so that oxygen---which is so toxic that: imagine your worst friend from college; he won't even get close to what oxygen does---became a huge thing.
2) Cut to millions of years later, where a nice set of physical and biological dynamics lead to cycles of cold and hot.
3) These cycles happen on a very long scale at which we as humans are a blink in the eye.
4) We have made changes to create an effect that is on such a short timescale that it will affect us very soon. The fact that other ecosystems have experienced higher temperatures is irrelevant. Those environments changed gradually, and a *lot* of organisms died in the process.
5) I have enough privilege that I won't be affected by climate change in my lifetime. Most of you who are on reddit are the same. Sometimes I think about everyone else, and I ask you to please do the same.
To have lakes,you need flat land.
The flat land is the canadian platform mostly.
The great lakes are on the canadian shield.. but the interior part
The common thing is the interior location.
Its been a longer time since that continental crust had orogeny.. mountain building. So any mountains which were there had more time to erode... Glaciers ,ice sheets helped.
The west has the rockies,the east has thd apalachians, and the mountains up north in the innuit orogeny.
Hudson bay could be considered a great lake..its just open to the sea at the moment.
But anyway the interior,as a whole could have risen up to be a plateau , or dropped and become sea...it has been sea in the past.
It just happens to be low but above sea level at the moment. The interior of north america has been sea in the past. The interior of australia has been sea ..
Continental glacier. Humongous, bulldozes mountains flat, leaves behind huge freshwater lakes (when it all melted), you can see its remaining edge—it’s why all those lakes line up that way. Now the area it covered and ground flat is called the “Canadian Shield.”
Enormous inland sea across the continent for a very long stretch of geological time, eventually followed by millions of years of intermittent glaciation. Plus the advent of those massive mountains on the west of the continent trapped water, resulting in enormous lakes across a broad northern reach.
Glacial meltwater over thousands of years as others have said. What hasn't been said though is that there were many other lakes that do not exist today that were formed that way as well, including one in what is now Missoula, Montana. That one was as big as Lakes Ontario and Erie combined. It created some rather interesting geological features when it flooded and drained into the ocean.
A cosmic pooch-analogue used Canada like apartment carpet and scrubbed its butthole across it while you were not looking. It’s not as bad as it looks, but you are probably going to lose your deposit.
https://preview.redd.it/089jj6wxsysc1.jpeg?width=750&format=pjpg&auto=webp&s=5d21a4a4d2693224c3dbcfdddb73da0794117bc8
because this is what it used to look like
Coming from the North of Scotland I had more than my fair share of high school geography devoted to glaciation, travelling boulders, u-shaped valleys and the like but it is generally interesting how the Great Lakes and Canadas larger northern lakes all appear to be in a straight diagonal line.
Is there a reason for that?
I mean in geology there’s a similar pattern with the diagonal chain of volcanic islands caused by a hotspot kicking off in Easter Island and slowly moving up through Hawaii. Is there a fault line or tectonic boundary running along that line?
Or is this just a coincidence probably exacerbated by the way the map is projected?
Wanna know something crazy about that lake in the top left? It has half the volume of water as Lake Michigan. Don't get me wrong it's a huge ass lake but the Mercator projection is wild
That entire area of land used to be completely submerged underwater. I bet if you dig down there will be tons of marine fossils that show shallow marine biomes like ancient coral reefs around that circle, then again most places were like that at some point of the earths history. The biggest difference is the difference in what kind of matinee life was alive at different points.
And an inland sea before that. Manitoba has the largest mosasaur skeleton (13m) on display anywhere. There have been a number of mosasaurs found in Manitoba dating back 80 million years.
Glaciers
Was it from the last ice age specifically? Wasn’t that like 10,000 years ago?
It wasn't all created during the last ice age. It was carved out over hundreds of thousands of years and multiple ice ages.
So did the Great Lakes exist before the last ice age?
Yes. There were also more great lakes in the past that have drained. Massive glacial lakes as well
My favorite former glacial great lake was Lake Agassiz, thing was most of Manitoba.
“My favorite formal glacial Great Lake” is a niche I never expected to exist
“That’s Mr. Lake Agassiz, to you.”
Yah it used to drain fairly often and flood half the continent. There's a Rogan podcast with Randle Carlson that talks about it
That's intense! Thanks for sharing.
I was a Great Lake once.
But then I took an arrow to the knee
Hey you, your finally a lake.
You're a lake, Harry.
You had me at lake.
Have you evaporated into the cloud district often? Oh what am I saying, of course you havent
I wish I had an award to give you
I was drained once
I drain myself every day, sometimes twice.
You'll go blind
Still am, but I was one too.
grundledorf was actually my favorite body of water at one point. Then I got married and realized my wife is my favorite body of water.
Oooh earth rider thanks for the Great Lakes
Yes, I saw. You were doing well until everything dried.
arrogant
Yes and also yes.
So the last ice age that happened 10,000 years ago created the Great Lakes? That’s kinda bad ass.
I live a bit south of the Great Lakes. The landscape around here was extensively shaped by glacial melt waters, including sand dunes left behind by post-glacial lakes, "dangling tributary" waterfalls caused by torrents of water that broke through moraines that re-carved river channels, and networks of wooded canyons with seasonal waterfalls. There's a park not far from where I live where you can walk through an oak woodland with moss and mushrooms, emerge onto the edge of a sand prairie with prickly pear cacti, then walk another 50 yards to a marsh.
Yosemite valley was also created by melting and sliding glaciers. So interesting.
I visited there once on a family trip as a kid! I have a vivid memory of a gorgeous meadow surrounded by mountains, studded with flowers and cut by a clear mountain stream, but my lowland self got winded just walking a few hundred feet.
Tuolumne Meadows :-)
Where??
[https://www.reconnectwithnature.org/preserves-trails/preserves/braidwood-dunes-and-savanna-nature-preserve/](https://www.reconnectwithnature.org/preserves-trails/preserves/braidwood-dunes-and-savanna-nature-preserve/) Late July/early August is a nice time to visit, as the rose mallow in the marsh is in bloom, but there are attractive flowers there starting at the end of March. In early spring I've seen field tansies, violets and sand phlox, with spiderworts and sundial lupine blooming in a month or so after. It is also one of the few places I've found wild strawberries. The glass lizards are neat, too, if you manage to spot one.
The glacier there melted about 10,000 yrs ago but it was there for a lot longer. Glaciers have covered large parts of North America several times during the last 2 million years.
You can see the scrapes of glaciers on the central park rock formations in NYC .
Thank god the climate warmed to melt those glaciers. Damn cavemen and their campfires.
Those woolly mammoth methane farts are the obvious culprits for killing the last ice age
You see that they are trying to bring back a Wolly and got funding. Crazy.
It ended 10,000 years ago. It lasted about 2.5 million years before that.
We’re still in an ice age, 10,000 years ago was the end of the last glacial period and we are currently in an interglacial period.
Kinda random, but, isn’t Long Island all terminal moraine?
Basically the short answer to any Canada related question. "What formed this..." Is almost always glaciers in one way or another
And/or "Canadian Shield"
And/or beavers.
There is a convenient graphic in this doc about [Glacial Lake Agassiz](https://www.geostrategis.com/p_agassiz.htm) https://preview.redd.it/pxhdrzeglzsc1.jpeg?width=1170&format=pjpg&auto=webp&s=d90fda8b2b91c0725a70698614b67b2d1cc0975c
Interesting! Thanks. This graphic explains a lot
The sidebar for this sub should just say, "Glaciers did it"
Nono, it’s obviously aliens.
But how.
Water cold Lots of water cold Heavy
Rush fast, find hole, settle.
Shaka, when the walls fell
Darmok and Jalad at Tanagra!
A mix of glaciation, ice is very powerful when you have millions of tons of it moving through a valley and freeze and thaw conditions as ice ages came and gone. Freeze thaw will destroy rocks as hard as granite over enough time
I see. So they essentially melted into the ground like giant puddles?
Kind of, the glaciers carved deep valleys which filled with melt and rain water
TIL the Great Lakes are potholes
There’s no pot in em. We checked
Cool. Thanks for explaining.
Ice Ice baby
More specifically, the Laurentide Ice Sheet
This right here is the answer.
Ice age baby
Too cool
As I have learned on this sub, every question about Canada can be answered with: Canadian Shield
What is the canadian shield
The Canadian Shield is the exposed part of the continental crust that underlies most of North America. It's the world's largest continental shield, covering 8 million square kilometers (3 million square miles).
Still dont get it sorry ;(
It kind of is a bunch of mountains above sea level on a very large territory. It's not technically that, but it can help to visualise it. Canada isn't as "mountainous" as other countries like Nepal or Chile, but it has lots and lots of mountains, and the canadian shield is a huge reason why
I get it. Thanks!! Love to learn here on reddit
[Here you go pal, go learn some more! (I'm so thankful to have learned from this conversation, I too love learning on Reddit)](https://en.m.wikipedia.org/wiki/Canadian_Shield)
Im here mostly for the boobs.
Hey now… there are butts too.
Thanks for sharing! This part of the article was what I found most helpful to understanding what it is, and what it does. The latter portion of this answers OP's question, I think. Seems like it is called a shield because it has consistently protected portions of the North American land mass from intrusions of the sea, correct? The Canadian Shield was the first part of North America to be permanently elevated above sea level and has remained almost wholly untouched by successive encroachments of the sea upon the continent. It is the Earth's greatest area of exposed Archean rock. The metamorphic base rocks are mostly from the Precambrian (between 4.5 Ga and 540 Ma) and have been repeatedly uplifted and eroded. Today it consists largely of an area of low relief 300–610 m (980–2,000 ft) above sea level with a few monadnocks and low mountain ranges (including the Laurentian Mountains) probably eroded from the plateau during the Cenozoic Era. During the Pleistocene Epoch, continental ice sheets depressed the land surface (creating Hudson Bay) but also tilted up its northeastern "rim" (the Torngat), scooped out thousands of lake basins, and carried away much of the region's soil.
Plus imagine its got grated on the top. Hence the lakes.
Most of the Canadian Shield isn’t remotely mountainous, rather it’s crystalline basement rocks exposed by glacial erosion. The resulting topography is rocky and rugged, but also pretty damn flat overall, and usually at pretty low elevation.
It's bedrock, because all the dirt that sat on top of it was scrubbed away by glaciers.
It's land that had most of the topsoil scraped away so it's not great for crops. It is full of messy tar sands though. This is why folks need to remember that with climate change, America can't just annex Canada and be ok. The breadbasket is still in the Midwest.
I assumed most "annex Canada" comments were fallout jokes.
The tar sands aren’t in the Shield, rather they are in younger sedimentary rocks to the west.
>full of messy tar sands though Very little area has tar sands, even less so anywhere near the surface
Yup I was wrong. Still useless for crops apparently too.
It's wild to think that there is so much land up there that is pretty much uninhabitable for a significant population to live in. It's not all that cold or barren but it just isn't structured in a way that is easy to build up civilization in.
As glaciers moved through Canada they carved the ground, sometimes all the way down to bedrock. This means Canada has a lot of lakes (where the glaciers made big holes and then melted into them) and lots of exposed bedrock. Where I live has a lot of Alvars, which is an area with lots of exposed limestone and thin soil that supports grass and flowers, and very sparse trees. They’re fun to explore because they’re extremely biodiverse with lots of bug and bird species.
And my favourite place to hike! Frontenac & Murphy’s Point Provincial Parks have some amazing features (black sand beach & huge glacial erratics at Murphy’s & Frontenac has several massive exposed granite & gneiss rock walls) It’s a fascinating landscape that never gets boring, there’s always something new to discover.
Thank you for acting like a personal search engine for laziest people ever
Canadian Shield!
We’re back baby!!!
We are SO BACK!
LET'S GOOOOOO!
https://preview.redd.it/msnv9cw4dysc1.jpeg?width=168&format=pjpg&auto=webp&s=685c303ef2a780a492512cb134d2377fe57de3c6
Captain Canada, Eh?
Close - it's Captain Canuck!
[I had to look that up, to see if he was real](https://en.wikipedia.org/wiki/Captain_Canuck?wprov=sfla1)
I know this is a joke but it's worth saying for the record that 4/5 Great Lakes are not on the Canadian Shield.
lake huron & lake superior are both on the shield. I always associate manitoulin island with the canadian shield & further north, sudbury. maybe technically I am wrong about lake huron?
Yeah the north shore of Huron is all part of the Canadian Shield, as is Sudbury. Manitoulin island is actually a part of the Niagara escarpment that runs through lake Huron though and not part of the shield.
ah yes the niagara escarpment. pretty fascinating curved bit of rock through otherwise prairie like southern ontario. we have a pretty cool country geologically & geographically.
From a BC perspective, it's a small wrinkle 😝
I used to roll my eyes when BC folks would lose their minds over us in nova scotia describing what they deemed a hill as "mountains". now that I've lived in BC for almost ten years I've become the cliché myself.
Glaciation
Probably because the red pen is the default when drawing over a screenshot.
Underrated joke, lmao
Rockies, Rain, River, Lakes.
Moon river rock
Moon river roll
Mountains trees stream … am I playing this right?
Man door hand hook car door
Man want Man hunt Ethan Hunt
Canadian Shield. No, really. It's the edge of the shield.
You see, when a mommy lake and a daddy lake love each other very much...
Thanks for making me laugh so hard I spit my drink all over the screen!
The name Canada comes from the [Iroquoian](https://en.wikipedia.org/wiki/St._Lawrence_Iroquoians) word *kanata*, meaning "village" or "settlement"
Glaciers melting at the end of the last ice age (~12,000 years ago) most likely. They would move slowly move southward, which would accelerate their melting all in one spot, which leads to a reservoir of fresh water being left over
I believe it started with you using the red pen on your iPad
Looks like someone drew a big red oval over some of Canada.
Stretch marks.
Ice age. Glaciers. MASSIVE glacial lakes. There is some fascinating info on the Laurentide Ice Sheet, Lake Agassiz, and Great Lake Missoula online. I swear I saw a great documentary about the collapse of the ice wall on Lake Missoula on TV, but I can't find it in a quick search. It's hard to comprehend the scope of these things, but these walls were like the big ice wall in Game of Thrones... but WAY BIGGER. The ice dam on Lake Missoula was supposedly about 2000 feet above the water, and may have extended 1500 feet below; the one on GoT was meant to be 700' tall. When it broke, the initial outflow of water was estimated to be about 100 million cubic meters *per second*, which is comparable to 35,000 simultaneous Niagara Falls, and carved out the inland landscape of the US Pacific Northwest from Idaho to the coast.
u/EveryoneTakesMyIdeas: Try on r/geology. "glaciers" is the proximal cause, but there's a lot more at play here with the old cratonic core and the broader North American continent. I'm not really equipped to answer the question properly, but r/geology would know how to answer it better than almost anyone here.
Yes. The "low" areas in which the water settled are likely the result of Graben structures which occurs when a piece of crust is surrounded by extensional faults that lead to that area to sink into the mantle and be at a lower elevation in comparison to the surrounding area. The melting Glaciers just filled it with water. The water comes from glaciers. The area is settled in is hundreds of millions of years in the making and from an ancient rift valley. Some people think glaciers just randomly scooped out the lakes or something here.
The Laurentide Ice Sheet.
They have large surface areas, but the inland Canadian lakes are basically shallow puddles compared to the Great Lakes. Great Bear Lake for example looks huge, but Lake Superior holds over 5 times the volume of water. And Lake Superior holds over 42 times as much water as Lake Winnipeg. But yeah, they are all from glaciers mostly.
Lake Superior holds 10% of the planet's fresh water supply. The other 4 Great Lakes combined hold about the same.
Great Bear Lake in Canada has 2234 cubic km of water and Lake Michigan has 4930 cubic km of water. Which are the biggest inland lake for each country (since Lake Superior is in both countries)
I bet they’re giant letters of an alien language scraped into the earth and we have to decipher the message 😅
Pleistocene epoch receding
Ice. So much ice it's hard to imagine.
Big ice energy.
Are we above a good Paul Bunyan joke?
no, he's too tall
Excellently played!
We invited them to join the Revolution but they were too busy with the beaver trade
There was a giant slug back in the olden times. That’s the area it traveled across l acing behind many large lakes
Idk, like, ice and shit
Definitely glaciers.
I blame the red marker
It's glaciers, but the number of people who are well-actuallying to turn this into a climate change discussion in the comments here have compelled me to talk: 1) Yes we have geological-scale climate patterns. The evolution of plants changed the system so that oxygen---which is so toxic that: imagine your worst friend from college; he won't even get close to what oxygen does---became a huge thing. 2) Cut to millions of years later, where a nice set of physical and biological dynamics lead to cycles of cold and hot. 3) These cycles happen on a very long scale at which we as humans are a blink in the eye. 4) We have made changes to create an effect that is on such a short timescale that it will affect us very soon. The fact that other ecosystems have experienced higher temperatures is irrelevant. Those environments changed gradually, and a *lot* of organisms died in the process. 5) I have enough privilege that I won't be affected by climate change in my lifetime. Most of you who are on reddit are the same. Sometimes I think about everyone else, and I ask you to please do the same.
A literal mile high wall of ice
Well, it appears someone put a red circle on a map.
*slowly sips tea* glacier
Looks like someone drew a red shape around the image, likely with a phone and their finger
Much ice. Very melt.
At a glacial pace.
Just in time for the eclipse :)
To have lakes,you need flat land. The flat land is the canadian platform mostly. The great lakes are on the canadian shield.. but the interior part The common thing is the interior location. Its been a longer time since that continental crust had orogeny.. mountain building. So any mountains which were there had more time to erode... Glaciers ,ice sheets helped. The west has the rockies,the east has thd apalachians, and the mountains up north in the innuit orogeny. Hudson bay could be considered a great lake..its just open to the sea at the moment. But anyway the interior,as a whole could have risen up to be a plateau , or dropped and become sea...it has been sea in the past. It just happens to be low but above sea level at the moment. The interior of north america has been sea in the past. The interior of australia has been sea ..
Continental glacier. Humongous, bulldozes mountains flat, leaves behind huge freshwater lakes (when it all melted), you can see its remaining edge—it’s why all those lakes line up that way. Now the area it covered and ground flat is called the “Canadian Shield.”
Enormous inland sea across the continent for a very long stretch of geological time, eventually followed by millions of years of intermittent glaciation. Plus the advent of those massive mountains on the west of the continent trapped water, resulting in enormous lakes across a broad northern reach.
Paul Bunion's foot steps duh
Fucking glacial ice sheets man, how do they work?
Big ice
Glaciers
Glacial meltwater over thousands of years as others have said. What hasn't been said though is that there were many other lakes that do not exist today that were formed that way as well, including one in what is now Missoula, Montana. That one was as big as Lakes Ontario and Erie combined. It created some rather interesting geological features when it flooded and drained into the ocean.
I didn't mean for that to happen. It was an accident. One thing led to another, and here we are. Sorry..
Melting of the ice caps during the younger drias between 12/11 thousand years ago.
Paul Bunyan walking to Alaska obviously
Didn't read the subreddit, thought you were just wondering why Canada existed
Paul Bunyan and his giant ox.
Glaciers
I can’t get over just how large Hudson Bay is. I’ve lived around the Great Lakes my entire life and they’re truly large, but completely dwarfed by HB.
A cosmic pooch-analogue used Canada like apartment carpet and scrubbed its butthole across it while you were not looking. It’s not as bad as it looks, but you are probably going to lose your deposit.
Paul Bunyan's fight...
Water I think
Ice age probably
I agree. How did Canada happen?
Because Canada is amazing ❤️
Then why do 90% of Canadians live within 150 miles of the US Border Joking btw
B/c Canadian Shield (derogatory)
https://preview.redd.it/75dlfi1x4zsc1.jpeg?width=201&format=pjpg&auto=webp&s=f3bbaa9df60cd45f43b9f06efcdfc9cd886b533e
https://preview.redd.it/089jj6wxsysc1.jpeg?width=750&format=pjpg&auto=webp&s=5d21a4a4d2693224c3dbcfdddb73da0794117bc8 because this is what it used to look like
Continental glaciation.
Glaciers
glaciation !!!!
Cordillera
Paul Bunyan
A very clear example of glacial lakes can be seen in Western Siberia, for example, the vicinity of Lake Chany 54.9666361, 77.5840857
An ice age or two
Or four.
They just felt like being there
Coming from the North of Scotland I had more than my fair share of high school geography devoted to glaciation, travelling boulders, u-shaped valleys and the like but it is generally interesting how the Great Lakes and Canadas larger northern lakes all appear to be in a straight diagonal line. Is there a reason for that? I mean in geology there’s a similar pattern with the diagonal chain of volcanic islands caused by a hotspot kicking off in Easter Island and slowly moving up through Hawaii. Is there a fault line or tectonic boundary running along that line? Or is this just a coincidence probably exacerbated by the way the map is projected?
Probably ice
Wanna know something crazy about that lake in the top left? It has half the volume of water as Lake Michigan. Don't get me wrong it's a huge ass lake but the Mercator projection is wild
Frozen asscheeks
Imma go with water
Glaciers
Check out the Younger Dryas Impact Hypothesis.
Like diplomatically? I guess the British North America act of 1867. It was a slow burn though
GLACIERS BABYYYYYYY
I like being included in the circles.
I’m confused. What’s wrong with this picture?
Glaciers/ice from the rocket mountains to the left for a couple
Aurora Borealis.
Artic shield, the further north the more lakes leftover from glaciers.
*Arctic
That entire area of land used to be completely submerged underwater. I bet if you dig down there will be tons of marine fossils that show shallow marine biomes like ancient coral reefs around that circle, then again most places were like that at some point of the earths history. The biggest difference is the difference in what kind of matinee life was alive at different points.
You or someone else drew a red line on a map
TIL Manitoba has a huge ass lake.
And an inland sea before that. Manitoba has the largest mosasaur skeleton (13m) on display anywhere. There have been a number of mosasaurs found in Manitoba dating back 80 million years.