Eli5 The Laramide orogeny.

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What makes it happen . I live next to the water pocket fold and dont understand how it happened when I google it .

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Anonymous 0 Comments

Like most mountain-building, the Laramide orogeny is a result of plate tectonics.

As you probably already know, the Earth’s surface is made of a bunch of different plates: enormous areas of rock all bound together, floating on top of the mantle below them, and pressed up against other plates near their boundaries. The [North American Plate](https://en.wikipedia.org/wiki/North_American_Plate), for example, covers Mexico, the United States, Canada, Cuba, the Gulf of Mexico, most of the western Atlantic Ocean, and the eastern edge of Siberia.

Around 70 million years ago, the western edge of the North American Plate bordered an ocean, which sat on top of another plate called the Farallon Plate. The North American Plate was being pushed westward by the forces that would ultimately open what is now the Atlantic Ocean. Since continental plates sit “higher up” in the mantle than oceanic plates do, the Farallon Plate slid under the North American Plate. But the two plates were in contact, so the Farallon Plate applied enormous pressure to the western edge of North America.

Rock seems solid and rigid to human experience, but that’s just because we’re used to dealing with relatively small forces. Under extreme enough forces, rock can bend and buckle just like soft objects can, and the rock of North America did exactly that. Imagine taking a sheet of aluminum foil, laying it flat, and then squishing one side of it towards the other. As it buckled, it squashed up into high mountains, forming the modern form of what we now know as the Rocky Mountains. The fold you live near is basically one of the “wrinkles” of that folding, similar to the wrinkles you’d find in your squished aluminum foil.

In addition to the squishing, the North American Plate sort of “scraped” the top of the Farallon Plate as it went under, adding extra rock to the western edge of North America. Most of the west coast of modern North America – roughly from Nevada westward at the latitudes you’re talking about – is made from rock scraped off of (“accreted” from) the Farallon Plate.

This sort of process – the collision of two tectonic plates forming mountains – is one of the major ways mountains get built. The most famous example going on today is the Himalayas, which are still rising as a result of the Indian Plate (which, as its name suggests, covers roughly the area occupied by modern India) slamming into the Eurasian Plate.

Anonymous 0 Comments

Like most mountain-building, the Laramide orogeny is a result of plate tectonics.

As you probably already know, the Earth’s surface is made of a bunch of different plates: enormous areas of rock all bound together, floating on top of the mantle below them, and pressed up against other plates near their boundaries. The [North American Plate](https://en.wikipedia.org/wiki/North_American_Plate), for example, covers Mexico, the United States, Canada, Cuba, the Gulf of Mexico, most of the western Atlantic Ocean, and the eastern edge of Siberia.

Around 70 million years ago, the western edge of the North American Plate bordered an ocean, which sat on top of another plate called the Farallon Plate. The North American Plate was being pushed westward by the forces that would ultimately open what is now the Atlantic Ocean. Since continental plates sit “higher up” in the mantle than oceanic plates do, the Farallon Plate slid under the North American Plate. But the two plates were in contact, so the Farallon Plate applied enormous pressure to the western edge of North America.

Rock seems solid and rigid to human experience, but that’s just because we’re used to dealing with relatively small forces. Under extreme enough forces, rock can bend and buckle just like soft objects can, and the rock of North America did exactly that. Imagine taking a sheet of aluminum foil, laying it flat, and then squishing one side of it towards the other. As it buckled, it squashed up into high mountains, forming the modern form of what we now know as the Rocky Mountains. The fold you live near is basically one of the “wrinkles” of that folding, similar to the wrinkles you’d find in your squished aluminum foil.

In addition to the squishing, the North American Plate sort of “scraped” the top of the Farallon Plate as it went under, adding extra rock to the western edge of North America. Most of the west coast of modern North America – roughly from Nevada westward at the latitudes you’re talking about – is made from rock scraped off of (“accreted” from) the Farallon Plate.

This sort of process – the collision of two tectonic plates forming mountains – is one of the major ways mountains get built. The most famous example going on today is the Himalayas, which are still rising as a result of the Indian Plate (which, as its name suggests, covers roughly the area occupied by modern India) slamming into the Eurasian Plate.