Transform fault and spreading-rate data have been reexamined and a worldwide synthesis of relative plate

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motion made. Island chains and aseismic ridges, formed by plate motion over mantle hot spots, show the direction of motion of the plates over the mantle. It has been found that by adding a single constant to this relative motion synthesis, a system of absolute plate motion over the mantle can be established which satisfies the relative motion data and the island chain/aseismic ridge trend data. This evidence is used to support a theory of deep mantle convection whereby plumes rising beneath the hot spots provide the driving force for continental drift.

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