There is information which says that East European Platform sticks out at the Baltic Sea and, therefore, we can see the ordovican layer in Estonia whereas
crystalline Paleoproterosoic basement crops up in the Finland.
What does that mean? I see that other layers are cambrian and ordovican, which means that they were formed 500 and 400 mln years ago. Does it mean that East European Platform has formed 2 giga years ago when we had the Paleoproterozoic era? I ask because it is hard to believe that we could have the magma cristallization at that scale to solidify over the whole continents. I expect that these processes that shield formation has finihsed in the range 5-4 giga years ago and pretty solidified Earth existed for ~ca 2 bln years before Paloproterozoic ever begun. Why is that platform called Paleoproterozoic?