Open and closed rock cycles

The rock cycle is a traditional and widely employed pedagogical device. Most textbook depictions of the rock cycle show a closed circuit, unconnected to other cycles. Considering the foundation the rock cycle provides students when developing geologic histories, this closed character is problematic. Using Gould's paired metaphors of time's arrow versus time's cycle, a simple closed rock cycle is pure time's cycle and peculiarly ahistorical, that is, system evolution is denied or omitted. Present-day closed depictions of the rock cycle are inconsistent with modern views of the earth's history. Some possible pedagogic changes in response to the above argument are 1) to employ open rock cycle diagrams, with connections to other systems, 2) to discuss time's arrow and time's cycle with students, 3) to employ the term rock or earth system, instead of rock cycle, and 4) to replace the rock cycle with a host of depictions of other open systems, for example, that of a subduction-arc complex. -from Author