Here's a breakdown:

* Gneiss: A high-grade metamorphic rock formed from sedimentary or igneous rocks under intense heat and pressure. It has a distinct banding pattern.

* Schist: Another high-grade metamorphic rock with a more pronounced foliation (layers) than gneiss.

* Marble: Formed from limestone or dolostone under heat and pressure, it is a recrystallized carbonate rock.

These rocks were formed millions of years ago when the African and Eurasian tectonic plates collided, pushing up the landmass that would become the Alps. The intense pressure and heat transformed the original sedimentary and igneous rocks into their metamorphic forms.

While these are the dominant types, the Alps also contain some igneous rocks, mostly granite, which were formed during the uplift process. There are also pockets of sedimentary rocks that were deposited after the mountain formation.