Bokelmann, G., 2002, Which forces drive North America?, Geology, 30, 11, 1027-1030
Understanding the mechanism of plate tectonics is one of the most important
problems in the geosciences. Are the tectonic plates pulled and pushed from
the side as the Orowan-Elsasser model suggests or does mantle convection
play an active role in driving the plates? This question can be addressed
by studying the deformation of deep continental roots. The application to
North America shown here indicates that the deeper mantle moves at a higher
velocity than the North American plate and that the mantle plays an
important role in driving the plates. I suggest that this finding (1)
provides a natural explanation for why the motion of North America slowed
down dramatically during the past hundred million years and (2) predicts
North American motion to eventually come to a halt.
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