Accreted island arcs and cross-cutting batholithic belts of the North American Cordillera

The basement framework of the western Cordillera consists \nin large part of tectonically accreted island arc \nterranes and cross-cutting batholithic belts. The arc \nterranes are diverse in terms of magmatic history, \ntectonic disruption and basement relations, and represent \nseveral distinct systems. Terranes of the two \noldest systems occur in inner and outer belt positions. The inner belt runs from central Alaska to the \nnorthern Sierra Nevada. It was in its major developmental \nphases by the Devonian, and was constructed on \nimbricated North American continental rise strata outboard \nof a passive margin. The outer belt includes the \nAlexander Terrane (AT) of SE Alaska and younger amalgamated \narc terranes of the Alaska Peninsula and Queen \nCharlotte-Vancouver Islands.