Here's why:

* Glacial Erosion: Cirques are bowl-shaped depressions found in mountains, carved out by the erosive power of glaciers.

* How it Works: As glaciers move, they pick up rock fragments (called "glacial debris") and use them to scour and grind away at the mountain slopes. The weight and movement of the ice also contribute to the erosive process.

* Result: Over time, this erosion creates the characteristic steep, amphitheater-shaped hollows we call cirques.

Deposition plays a role in glacial landscapes, but it's not the primary force behind cirque formation. Glaciers deposit the eroded material (glacial till) elsewhere, creating features like moraines.