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16 votes
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Is there a reason most mountain ranges seem to run parallel to coastlines?

Mountain ranges are usually formed as orogeny where tectonic plates collides, known as convergent boundaries. The continental plates have less density than the oceanic plates and the buoyancy results ...
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11 votes

Origin of Andaman and Nicobar islands

The Andaman and Nicobar Islands are neither orogenic or volcanic in origin. They are in fact an accretionary wedge, i.e., an accretion of sediments and oceanic crust "scraped" from the ...
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6 votes

What supports the Rockies?

A way to understand Rocky Mountains is (as mentioned) to look at the destiny of the Farrallon Plate. In the collision with North America, it didn't subduct but rather slide under the lithosphere until ...
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6 votes

Do divergent tectonic plates destroy mountains?

Quite the opposite. Divergent boundaries can cause mountain (well, actually volcano) building, because upwelling magma is part of the rifting process. First and most importantly, the Mid-Ocean Ridge ...
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5 votes
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How are small mountains created?

There are no plate faults in Arizona (actually "plate boundary" is the term that we use - "fault" already has a different meaning, so it could be confusing), but there is still extension of the ...
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5 votes
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Are the Olympic Mountains (in Washington state) geologically unique?

Short answer: yes, there are other mountains which contains oceanic crust in their lithologies. The process you described as "the upthrust of ocean crust" is called obduction. The resulting rock ...
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5 votes

Do divergent tectonic plates destroy mountains?

I want to add some nice examples of how divergent plate movement can actually create mountains, not destroy them. Here are two photographs I took several years ago from the Red Sea rift near Eilat, ...
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4 votes

Do divergent tectonic plates destroy mountains?

Do divergent tectonic plates destroy mountains? The short answer is "no". Erosion destroys mountains. Period. Not slumping, not faulting, not "flowing back to flatness" in the absence of compression, ...
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4 votes

Do divergent tectonic plates destroy mountains?

Mountains tend to fault and collapse back to flatter ground once the building forces cease. This is a very slow process and rarely leads to the complete elimination of a mountain range. So, left on ...
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4 votes

What supports the Rockies?

This may not answer your question to your liking but there is fairly relevant research on the topic. I think there is still a debate about the causes of the recent (Late Cenozoic) uplift, however. ...
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3 votes
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Alpine schistosity

I think that notations S$_1$, S$_2$, ..., S$_n$ may well refer to any ordered orogenetic phases producing schistosity in any rock, anywhere, at any time Generally, yes. This is not only true for ...
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2 votes

Relative dating of granite pluton

What exactly are you trying to measure? some of the great North American and Andean batholiths have cooling histories of at least 20 million years, and maybe more than 50 million years. It is perhaps ...
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2 votes

What is the value of calculating the elevation of mountains in the past? (paleoelevation)

Compared to some other fields in geology, this one actually has immediate practical implications. By "knowing the history of mountains", you can learn a lot about processes that involve erosion, ...
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2 votes

Are the cores of every mountain range igneous?

examples of mountain ranges with sedimentary or metamorphic cores Mount Everest. At an elevation of 7000 metres and higher, it is all sedimentary rock. Below 7000 metres, it is metamorphic of ...
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1 vote

Are the cores of every mountain range igneous?

Orogeny (the building of mountains) is the result of converging plates, but the composition of the resulting mountain range will vary depending on tectonic setting: Subduction The subduction of an ...
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1 vote

Relative dating of granite pluton

The better site for sample collection would be the accessible site where it's possible to pick up a sample. Unless you have a drill rig or an excavator, you are limited to what's exposed. If you still ...
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