5

The example of the East African Rift was given in a different answer. Splitting of mountain ranges in two becomes even more apparent as you go up north from there. The Red Sea between Egypt and Saudi Arabia is a young new spreading ocean, that cuts through Precambrian mountains. Further north from there, the Dead Sea is a combined transform–rift zone ...


4

Divergent boundaries are going to form where the crust is weak and thin, a divergent boundary siis very unlikely to form in an existing mountain range. Imagine trying to pull apart a lumpy cookie, is it going to break through the thick lumps or the thin areas. That's not saying a rift could not cut across a mountain range but it will be very unlikely, it ...


3

No, earthquakes are sudden, often very energetic events which produce faults and discontinuities. There is a sharp break in the strata when subjected to a powerful earthquake. The folding of strata is a much more gradual process, where rock deep underground is subjected to enormous lateral pressure over millions of years. This pressure is caused by plate ...


2

The crust is actually getting thicker very gradually as the Earth cools down. This process is well seen on Mars, where due to its smaller size and greater distance from the sun, Mars is cooling faster than the Earth. No one knows exactly how thick the Martian crust is, but what we do know is that magma can no longer find its way to the surface. All the ...


2

If you want to know about what happens with diverging plates, the best example to look at is the East African Rift Valley. An existing plate is forced to split apart by a mantle plume or plumes, and this is likely to be accompanied by volcanism as is the case in East Africa. It is theoretically possible for the rift to cut through mountains, and this seems ...


1

Iceland isn't only situated on a divergent boundary (which in itself can rise up to shallow depths because of higher static and dynamic lift btw.) but also on a (postulated) pretty deep rooted mantle plume that may produce enough magma to rise to subaerial heights. Edit: The magma that erupts at an ocean ridge is "welded" to the sides ("sheeted dykes"). ...


1

The reason islands don't form along divergent plate boundaries is that these boundaries are at the bottom of the sea, and usually quite deep. Although mid ocean ridges are volcanic, the magma doesn't get a chance to pile up and reach the surface because the plates are not static. They are slowly spreading apart, and the magma is needed to form fresh oceanic ...


1

You are entirely correct. Todd and Engi write: The mineral assemblages of rocks at the surface lie on a locus of P–T-conditions… It must be stressed…does not imply a P–T-distribution or geotherm realized at any one time during the orogenic evolution of this area. Even assuming the P–T-values reflect maximum metamorphic conditions, these were ...


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