Ask A Scientist General Science Archive

Question: 
How can large mountains be formed when the plates are moving so slow?
 n bolinger

Answer:
Mountains can form to any size.  It all depends on how much momentum
the two plates have relative to each other when they collide.  Because of 
the high masses of the plates, the momentum (and hence the force)
during the collision can be extremely high (note the more powerful
earthquakes).  The Himalayas are extremely high (some 29000 feet I
believe) and are relatively new.  This is why they are so jagged.  The
Blue Ridge mountains on the East Coast of North America are very
old, and have been worn dorn over the millenia and are relatively
smooth now.  If this answer isn't clear enough, let me know, and I'll try
to expand on it.
 wildman jackson