An alternative vector derivation of the expression for the rates of plate creation and consumption is given, from which it can be seen that the rates are proportional to the scalar product of the edges of the geohedron and plate polyhedron corresponding to the same boundary. The plate polyhedron is defined by the set of triple junction vectors. This is used, together with a recent determination of the angular velocity vectors and a number of auxiliary plate boundary vectors, to revise the rates of plate creation and consumption along sections of plate boundaries. All plates which have a substantial proportion of their boundary connected to a downgoing slab are found to be decreasing in area. The total rate of plate generation is used in estimates of the area of the ocean floor and the total heat loss from the oceans. The rate of consumption within a relatively small area around New Guinea implies a large mass flux away from this region.-Author
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