at www.physorg.com/print198495599.html July 16th … a group of earth scientists has developed a new way to explain the global movements of tectonic plates on the surface of the earth. For example, the Basin and Range Province in Nevada was created by a plate sliding beneath the North American continent – just 30 million years ago.. This is fairly recent as far as geological time is concerned, and the paper, in Science July 16th, suggests plates in the modern world move at the rate of around a few centimetres per year. Plate boundaries converge at deep sea trenches where one plate can subduct beneath another – but the rate of velocity varies. It is this that is new – an explanation for the difference in speed of plate movement. Using observational data and advanced computer modelling they developed a mathematical scaling theory which demonstrates the velocity depends on the size of subduction zone and the presence of subduction zone edges. The fluid dynamics of a coin sinking through a jar of honey is compared to a subducting plate slowly sinking into the viscuous mantle of the earth – and the model assumes the current rates of movement are the same as what has occurred in the past.