Cordilleran terrane accretion in western North America

One of the key areas for unravelling the range of tectonic processes involved in the assembly of continents lies in the Western Cordillera of North America, made up of dozens of slivers of mutually exotic terranes. Their exposed upper parts remain largely intact and are dateable using fossils or radiometric dating. Through assiduous palaeomagnetic research it is sometimes possible to chart their motions over time to see the manner in which they approached and collided with one another. Geoscientists are now able to link such a complex process with underlying tectonics, not by inference but through direct seismological observation of the remains of subducted slabs in the mantle deep beneath.

The crumpled Farallon Plate beneath North America, colours showing different depths in the mantle (credit: Karin Sigloch)

This item can be read in full at Earth-logs in the Tectonics archive for 2013

2 thoughts on “Cordilleran terrane accretion in western North America

  1. Steve, as one of your constant readers I wish to thank you for keeping us informed in such a lively and illuminating manner. You help us to look beyond our specialised fields. In this case, the recognition of “slab walls”, I expect and hope that soon we shall learn what this means for metallogeny in the American Cordillera. Subduction plus volcanic arc stationary for long periods might well be one explanation for the amazing metal endowment of the region. Regards, Walter


    1. I never thought of the metallogenic implications, Walter. Thanks for making the suggestion. The paper was one of the most insightful that I have seen in the last few years


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