REVEL: A NEW GLOBAL PLATE VELOCITY MODEL AND CHANGES IN PLATE VELOCITIES OVER THE LAST 25 MA

We present a new model for Recent global plate velocities, REVEL. The model describes the relative velocities of 15 plates and three continental block, and is derived from publicly available space geodetic (primarily GPS) data for the period 1993-2000. We include an independent and rigorous estimate for GPS velocity errors in order to assess plate rigidity, and propagate these errors to the plate velocity predictions. Approximately two thirds of tested plate pairs agree with the NUVEL-1A geological (3 Ma average) velocities within uncertainties. Four plate pairs (Caribbean-North America, Caribbean-South America, and North America-Pacific) exhibit significant differences between the geodetic and geologic models that may reflect systematic errors in NUVEL-1A, probably due to the use of seafloor magnetic rate data in the geological model that do not reflect the full plate rate because of tectonic complexities. Most other differences likely reflect real velocity changes over the last 3 to 25 million years. Several plate pairs, including Arabia-Nubia and Arabia-Eurasia, appear to be slowing down, perhaps as a consequence of continental collision and subsequent increase in gravitational body forces resisting plate motion as crust thickens in the collision zone. For several other plate pairs, including Nazca-Pacific, Nazca-South America and Nubia-South America, gradual slowing reflects longer term deceleration dating back to about 25 Ma, the time of the initiation of the Andes mountains.