Gregory's Server
@VeroniqueB99 They're pretty ancient mountain ranges, certainly. But aren't mountain ranges created by the collision of tectonic plates? That would mean before there was Pangea, there must have been a couple other plates drifting around that collided to form it. And the subsequent breakup may just be a rebound effect from that previous collision.
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@hyc @VeroniqueB99 Not all mountain ranges were formed the same way or at the same time. Some formed before the great divide, as is the case here. In the Permian period, the Central Pangean dealt with physical weathering that decreased the peaks and formed intermontane plains. By the Middle Triassic, the mountain sierras had lost most of their size. In the Jurassic period, the Pangean became separated by deep marine basins that later became oceans. @santoperdido @hyc @VeroniqueB99  @hyc @VeroniqueB99 Remember continents are just the lightweight cold skin atop the slowly percolating and circulating mantle, that’s the engine of the large-scale dynamics.  @hyc @VeroniqueB99 When a continentel shield gets too thick, heat will concentrate under it resulting in more magma flow and eventually forcing the continent apart. |
@hyc @VeroniqueB99
I don't think it was simple rebound, but Yes there were several plates moving around before, during, and after Pangea. The history of it all is pretty well mapped out these days, iirc. Continents move slowly, but when they cram a billion years into a 5 minute animation it sure looks fast.