Oceanic Plateaus and Continental Growth

Some oceanic plateaus have arc systems erupted along their margins. These arcs obducted at shallow levels onto continental crust during collision and obduction. In spite of the fact that in some cases that thick slices of oceanic plateau can also be obducted or underplated, arcs should greatly dominate in obducted fragments.
The oceanic plateaus, which collide with continents and lose their surficial arc by obduction, are accreted to continental margins and with time they develop to lower continental crust. This concept has implications for continental development in that the lower continental crust would comprise mainly accreted and underplated oceanic plateaus, whereas the upper continental crust would form by subduction-related processes, possibly beginning before accretion of oceanic plateaus to continental margins. However, most of the upper continental crust must develop after collision by subduction-related magmatism.
In order to establish young and accreted oceanic plateaus in the process of evolving into continental crust, there is a persuasive continental evolution model for oceanic-plateau accretion. It is well identified that the Mesozoic Cordilleran crust in northwestern North America is relatively immature and, on the whole, more mafic in composition than Precambrian cratonic crust \cite{Condie_1996,Patchett_1998} .