Richard Gordon, a geoscientist at Rice University in Houston, Texas, and collaborators Chuck DeMets of the University of Wisconsin and Donald Argus of NASA’s Jet Propulsion Laboratory in California, developed the model – named MORVEL, from ‘mid-ocean ridge velocities’ – as an improvement on a study they published in 1990.
About three quarters of the data for MORVEL came from mid-ocean ridges, the long undersea boundaries between plates where new crust forms as magma wells up from deep inside the Earth. These new data have allowed the scientists to improve the resolution of their model, particularly for the areas where the plates are spreading the fastest.

To estimate the speed at which the plates are forced apart at these ridges, Gordon and colleagues analysed the magnetic profiles of the crust formed along them. The polarity of the Earth’s magnetic field changes at irregular intervals – most recently, about 780,000 years ago – leaving a magnetic mark in the crust, much like a tree ring. The scientists measured the distances between these marks to determine how quickly new crust is being formed.

DeMets, the lead author of a paper on MORVEL published in Geophysical Journal International, said: ‘This model can be used to predict the movement of one plate relative to any other plate on the Earth’s surface. Plate tectonics describes almost everything about how the Earth’s surface moves and deforms, but it’s remarkably simple in a mathematical way.’

June 2010