Insular Islands were a giant chain of active
volcanic islands somewhere in the
Ocean during the Cretaceous
time that rode on top a microplate called the Insular Plate, beginning around 130 million
The Bridge River Ocean between North
America and the Insular and Omineca volcanic arcs
These islands collided then fused onto the
Mid-Cretaceous time. The Insular Islands were already very ancient
before they collided against North America. Like the earlier
islands were simply too massive to subduct beneath North America.
The Insular Islands jammed and shut down the subduction zone
. In its place, the
pre-existing Farallon Trench
over as the major subduction zone.