Ian Bliss of Northern Shield Resources has supplied me with a graphic which helps explain how the Ring of Fire 'came to be'.
If you go away back on the Agoracom SPQ board you will read about the conjectures of how the Ring of Fire came to be: meterorite, volcanism, combination of the two, etc. The work over the last two years by the great ROF geologists including Neil Novak and Jim Mungal have given us a much better picture as to the genesis and composition of the ROF.
It is a folded intrusion that has been altered by erosion. At my blog I have a larger graphic.
Snug