The magmas that formed the batholith were generated in response to the subduction of the Farallon plate beneath the North American plate. |
What remains unclear is whether the rocks formed in an open ocean or a marginal back-arc basin associated with a subduction zone. |
The tensional stresses in the uplift can be relaxed by, for example, underthrusting in a subduction zone, or contraction in surrounding regions. |
Around both zones accretionary wedges are indications of Cretaceous subduction. |
An alternative mechanism to open the rift basins is subduction rollback of the Indian plate to the west of Thailand. |
The most widely accepted view is that of an accretionary prism developed above an active subduction zone. |