1/ #GeographyTeacher quiz!
In the 1960s, Bruce Heezen was one of the first to connect the Mid Atlantic Ridge round South Africa to the Indian Ridge.
But he realised there was a problem: how could the Atlantic & Indian Ocean both be extending if Africa was in the middle?
2/ But he was operating with Harry Hess' convection cells model as the mechanism for moving plates: the plates are passive passengers, riding on large convection cells in the mantle. This is how Geoffrey Davies outline's Heezen's logic.
3/ Heezen, of course, was wrong: the Earth is not expanding.
So how then do we explain this arrangement of margins?
Here's a slightly wider context. Can you figure out how the plates move to accommodate this arrangement?
4/ One important clue - you have to put the neat convection cell model proposed by Hess (and perpetuated ever since in so many books and Google image searches) and embrace the model of convection more widely accepted today, as outlined below:
5/ Read more of this better understanding of plate and mantle dynamics in my recently released resource for @RGS_IBGschools on Tectonics, available here.
The answer to this specific problem will follow soon - once you've had a bit of thinking time! orlo.uk/ov5UU
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