How North America got its shape
We know that the geography of our planet is in flux. The major landforms and the features are continuously changing on earth . So today we are going to talk about North America and how the landscape over there has developed in millions of years .
750 Million years back
The Panthalassa Ocean was created due to rift of Rodinia continent along the west coast of North America.
The ancient continent created known as Laurentia kept growing over the next few hundred million years as the collision of island chains kept adding land mass to it.
400 Million years ago
The ancient Iapetus ocean got closed due to the movement of African plate westward.
At 250 Million years: This African plate collided with Laurentia and together they formed the supercontinent Pangea.
Down the line, the immense pressure caused faulting and folding which resulted in the formation of Appalachian Mountains
100 Million years later
The breakdown of Pangea led to the opening of southern Atlantic ocean between new North American plate and the African plate.
Later on with the eastward movement , Farallon plate got converged with present day west coast because of its greater density. Due to subduction water was diffused into the magma filled mantle. This magma travelled upwards and erupted along a chain of volcanos.
85 Million years ago
As the Farallon plate got less steep with time, North America got compressed and mountain ranges like Rockies got thrust up.
After this the Eurasian plate got drifted from North America and North Atlantic ocean came into existence. Due to the upward flow of mantle the Colorado plateau got uplifted.
30 Million years ago
Majority of the Farallon plate sinked into the mantle and a new boundary San Andreas Fault got formed after the convergence of North American and Pacific plates converged.
Here the north America started moving towards the south against the northward movement of pacific plate . Its interesting that this boundary still exists today and moves about 30 millimeters per year that can cause severe earthquakes.
The San Andreas also pulls apart western North America across a rift zone and this extension is called Basin and Range Province. This region due to upliftment and erosion is responsible for exposing the granite of Yosemite and Sierra Nevada.
15 Million years later
The magma from the mantle burnt a giant hole into western North America. Today this hotspot is feeding an active volcano beneath Yellowstone National Park.
This volcano has not erupted since last 174,000 years but if it did then the whole continent will have to wear a blanket made of ash.
We need to apprehend the fact the plates of our planet are continously moving and only geological time will tell us what shape will North America have after 100 years.