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As the interior of the earth cools, presumably there will come a time when the temperature gradient is insufficient to maintain the mantle plumes and hence plate tectonics.

How long will this take and what will be the consequences for the surface of the planet in terms of continent and ocean distribution and depths. Will it also affect the recycling of gases etc into the atmosphere?

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  • $\begingroup$ Can you point me to where you think this has already been answered. I did a search but came up blank - that is why I asked the question. $\endgroup$ – John Webb Dec 9 '18 at 19:21