For a long time, geoscientists have assumed that the Alps were formed when the Adriatic plate from the south collided with the Eurasian plate in the north. According to the textbooks, the Adriatic plate behaved like a bulldozer, thrusting rock material up in front of it into piles that formed the mountains. Supposedly, their weight subsequently pushed the underlying continental plate downwards, resulting in the formation of a sedimentary basin in the north adjacent to the mountains—the Swiss Molasse Plateau. Over time, while the mountains grew higher the basin floor sank deeper and deeper with the rest of the plate.
Click here for original story, Detaching and uplifting, not bulldozing
Source: Phys.org