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Structural Provinces

         Structural Provinces  are material units of continental crust that carry a  penetrative deformation fabric of a specific age. The age assigned to the  Province is therefore that of the orogenic event that caused the deformation  rather than the age of the rocks themselves. Where rocks bear the imprint of  several deformation events (polyphase deformation), the age of the youngest  event defines the age of the Province.
        The oldest structural provinces of the Canadian Shield are the Slave and Superior provinces (c. 2.7 Ga), and the youngest is the still active Cordilleran  system. Structural Provinces of Early Paleozoic age include the Appalachian  and Innuitian provinces marking the eastern and northern margins of the North  American continent.
        Structural provinces may themselves be composed of a collage of  ‘terranes’, each terrane representing an independently evolved oceanic (e.g.  arc) or continental (margin; microcontinent) unit that has migrated into its  present position perhaps quite far from its ‘birth’ location. The Cordilleran  Province provides a good example of such a collage (Cordilleran Suspect terranes). Similarly, the Grenville  Structural Province (Tectonic map of the western Grenville Province Arc ocean systems)  is thought to be an accreted collage of Proterozoic arcs  and successor basins that has collided with the southern margin of the Superior  Province and its cover of passive margin rocks forming the Southern Province. The  Grenville Province is highly deformed, metamorphosed, and injected by igneous  rocks, and its plate tectonic history is therefore not easily interpreted.  Nevertheless, it is not unreasonable that terranes such as the Parry Sound and  Elzevir domains represent allochthonous or parallochthonous Meso-Proterozoic  island arcs,
        The Precambrian structural province that most closely represents a two- sided collisional plate tectonic system is the early Proterozoic Churchill  Structural Province.  (The Churchill Structural Province) The Archean rocks forming the northwest margin of the  early Proterozoic Churchill ocean appear to be more extensively deformed than  those of the Superior margin, and in this respect the Churchill Structural  Province bears a marked resemblance to the Himalayan-Tibetan collisional  system, with however far more of the oceanic component preserved in the  Churchill Province.

Structural trends in the Canadian Shield
Cordilleran Suspect terranes
Tectonic map of the western Grenville Province Arc ocean systems
(Structural Provinces) of the Canadian Shield (14strprv.gif)
Tectonic units of the Canadian Shield of Manitoba and Saskatchewan.


Structural Provinces of North America.

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