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