The traditional conception of the rock cycle.

• textbook depictions.
• origin in Hutton's world view.

Two important metaphors - Time's cycle and Times Arrow.

Discussed by Stephen J. Gould, 1987, Time's Arrow Time's Cycle, Harvard University Press.

• "Judeo-Christian traditions have struggled to understand time by juggling and balancing two ends of a primary dichotomy about the nature of history. In our traditions, these poles have received our necessary attention because each captures an unavoidable theme in the logic and psychology of how we understand history -- the twin requirements of uniqueness to mark moments of time as distinctive, and lawfulness to establish a basis for intelligibility.
• At one end of the dichotomy - I shall call it time's arrow - history is an irreversible sequence of unrepeatable events. Each moment occupies its own distinct position in a temporal series, and all moments, considered in proper sequence, tell a story of linked events in a direction.
• At the other end - I shall call it time's cycle - events have not meaning as distinct episodes with casual impact upon a contingent history. Fundamental states are immanent in time, always present and never changing. Apparent motions are parts of repeating cycles, and differences of the past will be realities of the future. Time has no direction."

Is the standard depiction of the rock cycle that of a cycle or an arrow, and is it an open or closed system?

Significance of the metaphors.

What can be added to create a more powerful depiction of the rock cycle/system?

Above is my depiction of an open rock cycle. Reservoirs are depicted as yellow boxes, and the processes by which material transfers from one reservoir to another are given in purple. Believe it or not this diagram involves substantial simplification. Trace some paths through it to understand the connections better. What does such a diagram suggest about the nature of the earth's geologic history?

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