Volcanism in Virginia

I suppose that title is a bit misleading, there aren't any active volcanoes in Virginia, and there probably isn't going to be in human history.  However, Virginia does host quite the geologic oddity, something up until today I was completely unaware of.  48 million years ago, there was a bout of volcanic activity in Virginia, building up several mountains and in general rejuvenating the southern Appalachians, which is why they are higher and more rugged today than their northern counterparts.  48 million years is a long time, but considering that the last volcanic activity on the East Coast occurred 200 million years ago with the breakup of Pangaea, it's not nearly as long as it sounds.

Trimble Knob, the remnant of a 48 million year old volcano

This discovery itself is very recent, and scientists were completely baffled as to how something like this could happen in a geologically passive spot like Virginia, thousands of miles from any fault line.  Scientists may have an answer now.  The problem was that although the Virginia volcanoes resembled other hotspot volcanoes, the magma that formed them was not hot enough, the layer of magma was not thick enough, and the potential hotspot in question moved through 10 million years previously.  Also, the lack of volcanic islands off the Eastern seaboard further disproves the hotspot theory.  Instead, scientists believe that the crust below Virginia thinned through a process called delamination.  This allowed the slightly cooler magma to make its way to the surface.  This would explain the out-of-place volcanism and the fact that the mountains in the area are more rugged than they should be, considering their age.

Slight side note for fans of Kerbal Space Program: While looking up what delamination was exactly, I discovered that Moho was an actual geologic term, and not just a made up name for the innermost planet in the game.  The Moho is the boundary between the crust and the mantle.  Fun fact of the day.

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