I understand the physics of moving mass toward the centre of rotation increases the speed of rotation, but I thought it wise to make sure we were talking about the same thing before moving on.
since the earths crust already had angular momentum before the ice age relocated a vast amount of the earths ocean water to the poles , any movement of mass to the poles would add angular acceleration to the earths crust increasing the angular momentum of the earths crust. (increasing its rotational speed)
Two points are worthy of note here:
1. The build up of the vast thickness of ice took thousands of years. Over those same thousands of years local vertical movements of crust and upper mantle would take place as isostatic equilibrium was slowly restored. The maximum ice thickness would, roughly, be contemporaneous with the maximum crustal depression, thus minimising the effect you describe.
2. As far as I am aware the Mohorovičić discontinuity does not constitute a surface of slippage on a global scale. Perhaps I should look these things up rather than relying on memory, but where do you get the idea that the crust and mantle spin at different rates?
As I said above; I am aware that there is a difference between the rotation rates of core and mantle. The difference would be between inner core and mantle, and it is the core that rotates faster. What evidence do you have that the crust might rotate faster than the mantle?
You may point out that you didn’t say that, but if increasing rotational speed of the crust increases friction, then it cannot be because the mantle was formerly rotating faster.
I like your contraption, but it bears little, if any, relation to the situation in question.
