I’m trying to create a planet with two small polar oceans with equatorial supercontinent in the middle. The land is in turn divided in two by high mountains that act as barrier and a source of water for rivers flowing into oceans.
How the world came to be: during its early youth planet rotated very quickly (few hours) which created substantial equatorial bulge. Continental plates were pushed toward equator creating multiple uplifting zones, oceanic floors between them were subducted, continental cores mashed together in a crazy jumble of high plateaus and mountain chains with lots and lots of volcanoes. Polar regions were left flat but crisscrossed with mid-oceanic ridges and hotspot archipelagos.
After that initial migration geological activity suddenly slowed down. The resulting uplifted regions were left frozen in place. The byproduct of this is CO2 depletion and very poor biosphere, but it's nothing that can’t be dealt with by terraformers, at least on human timescales.
Thanks to tides and a moon planetary rotation slowed a bit (the day is still 16 hrs. long). Centrifugal pressure weakened, atmosphere on the equator thinned a bit, water flowed toward poles, collecting in polar basins and flooding landmasses that didn’t move toward equator.
Result: polar oceans and equatorial supercontinent with mountains, glaciers and high plateaus in the middle. There are also gigantic valleys, which drain rain and melt water. Because equatorial bulge contributes to the elevation of the supercontinent above sea level, its more northern and southern parts consist of continental slopes and exposed basaltic oceanic floor.
Those ancient oceanic plains are now covered by sediments, and are flat. Very flat. They make a place where winds can blow around the whole world not encountering any obstacle. Coasts are muddy plains, where tides move tens of miles there and back again. Rivers the size of Nile, flowing toward oceans from the equatorial mountains fall from old continental slopes and escarpments in gigantic waterfalls and cataracts.
Does this scenario makes sense and is at least plausible?
(I’ve read this question: Climatic consequences of two Polar Oceans and a Circumspecting Landmass Definitely I’m using it for building climate but first I want to know how to make such configuration of land and water).