Just was woundering

Was the pacific coast of North Amarica at one time an Island Chain?(Island Chain what Japan is right now, a serise of volcanos above sea levle and the Lava filled in the gaps forming a coast line)

Just was woundering?

If you look at the mountain range that runs along the West Coast of North America, the Sierra Nevadas, you see that what's responsible here isn't volcanism but a cataclysmic collision.

As the Pacific plate slid eastward and the North American plate slid westward, where they met, two things happened. First, the North American plate was forced upwards and the Pacific plate downwards, the result being the Sierra Nevadas. Second, pressure built up farther out to sea under the Pacific plate, forcing magma up to the surface, lifting the crust above the water and creating most of the West Coast of North America.

No, the pacific coast was not an island chain. It could become one, however, because of how the tectonic plates are moving. Parts of California and Washington could separate from mainlaind.

emmymarron, the Pacific and North American plates travel in precisely the wrong directions for that scenario to ever take place, barring some major shift in magma currents. The Pacific and North American plates are currently traveling north/south in relation to each other, and Washington is bordered by another plate altogether, called the Juan de Fuca. So the West Coast is in no danger whatsoever of breaking off from anything.