Chapter 3

McKenzie on extensional basins


“You get perhaps five kilometres of rock, all of which was deposited round about sea level. This was the great puzzle. How do you form a basin like that and what causes it to subside? Out of the Aegean came the idea that this wasn’t plate tectonics, it was absolutely the antithesis. So the first thing that happens is that you get a lot of normal faulting and a lot of erosion into those fault-bounded basins. And then, when the extension stops, the lithosphere has been thinned and cools back to its original thickness and you get thermal subsidence, just as you do on the ridges.”

Page of McKenzie’s calculation notes on sedimentary basins.