Fold mountains
Hi, Don–
The Scientific American of Sept. 1983 has an article that says "Behind the
volcanic arc the overriding plate may be extended or compressed. … If the
extension of continental crust behind the arc proceeds until new oceanic crust
is formed, a marginal sea will result. …just as the marginal sea called the
Sea of Japan intervenes between Asia and the islands of Japan."
Again, it says "Occasionally, the divergence of two continental bodies occurs
near an older continental margin, and fragments of continent are rafted away to
form small plateaus of continental crust partially or entirely submerged in the
oceans and surrounded by oceanic crust. Examples include the Lord Howe Rise
(with its highest part, New Zealand)…". It goes on to say New Zealand split
off about 100 million years ago.
Thus both New Zealand and Japan are fragments separated from Australia and
Asia, respectively.
–Doug