For terranes with complex geologic histories, the chosen color indicates the tectonic environment most prevalent during this history of the terrane. For simplicity, post- accretionary sedimentary, volcanic, and plutonic rocks are combined into individual postaccretion units. These overlap assemblages and basinal deposits formed mainly during sedimentation and magmatism that occurred after accretion of terranes to each other or to a continental margin. Overlap assemblages provide minimum ages on the time of accretion of terranes. Some Cenozoic and Mesozoic overlap assemblages and basinal deposits, as well as fragments of terranes, are extensively offset by movement along postaccretion faults.
Significant differences exist between the representation of onshore and offshore geology.
Several key geologic sources were used in the compilation of the map. Accretion Tectonic juxtaposition of two or more terranes, or tectonic juxtaposition of terranes to a continental margin. Accretionary wedge and subduction zone terrane Fragment of a mildly to intensely deformed complex consisting of varying amounts of turbidite deposits, continental margin rocks, oceanic crust and overlying units, and oceanic mantle. Divided into units composed predominantly of turbidite deposits or predominantly of oceanic rocks. Units are interpreted to have formed during tectonic juxtaposition in a zone of major thrusting of one lithospheric plate beneath another, generally in zones of thrusting along the margin of a continental or an island arc.