Fold and thrust mountain chains are contractional features, formed when two tectonic plates collide, forming great thrust faults and folding metamorphic rocks and volcanic rocks. By examining and mapping the structure in the belts we can reconstruct their history and essentially pull them back apart in the reverse of the sequence in which they formed. By reconstructing the history of mountain belts in this way, we find that many of the rocks in the belts were deposited on the bottom of the ocean or on the ocean margin deltas and continental shelves, slopes, and rises. When the two plates collide, many of the sediments get scraped off and deformed, creating the mountain belts; thus fold and thrust mountain belts mark places where oceans have closed.
The Appalachians of eastern North America represent a fold and thrust mountain range. They show a detachment surface, or decollement, folds, and thrust faults. The sedimentary rocks in the mountain belt are like those now off the coast, so the Appalachians are interpreted to represent a place where an old ocean has closed.
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Preparing for Armageddon, Natural Disasters, Nuclear Strikes, the Zombie Apocalypse, and Every Other Threat to Human Life on Earth. Most of us have thought about how we would handle various types of scenarios that could signal the end of the world. There are plenty of movies on the subject, psychological papers, and even survivalists that are part of reality TV shows. Perhaps you have had dreams about being one of the few left and what you would do in order to survive.