Not necessarily... Same water... just frozen and piled up in places. The weight of the glaciers actually deformed the crust in some points so much that when the ice melted, the magma pushed the crust back up... This is how some rock at the tops of mountains was once sea bed...
Well, that and crustal boundary layers, obduction and subduction zones, etc...
There’s a local beach where you can see bluffs of strata heaved up at about 45 degrees. That occurred about 14 million years ago, I believe. Atop them are a number of feet of sandstone...former ocean bottom, a hundred feet above current sea level. In the intertidal zone are some large cedar stumps, from trees that lived a few hundred years ago, that were dropped below current sea level in a big earthquake in 1700. Cascadia Subduction Zone. Hell of a ride.