Westward subduction along the axis of the marginal sea consumes the east half beneath the west half. Volcanic terranes now comprising Sonomia and Stikinia grow on the overriding west half of the marginal sea, and approach the miogeocline. Collapse of the arc into a chord drives part of the marginal sea and distal miogeocline northward on a transform fault (white line).

Go back to the Animation

Go to still graphics of:
Late Triassic
Middle Jurassic
Early Cretaceous
Middle Cretaceous
Late Cretaceous
Late Paleocene