I mean, while we're waltzing around the absurd, how meaningful do you really think the continents remain at magmatic depths? We're literally talking about the space where the bedrock melts and flows in the unknowable oceans of Sauron's marmalade, after all. I think the ring spent eons swishing around before reassembling like a blended up sea sponge before making its way back to the surface in the modern-day land of the elves (Iceland). It's only a matter of time before the trolls in the forests of Norway begin amassing their forces. As for that video's narrator, I think his name is Dave Sméagol, so I'd take his misdirections with a pinch of salt.