How can a valley glacier modify the mountainous area where it forms? what glacial features form the mountainous area?

Valley glaciers form cirques, arrettes and U-shaped valleys in mountainous areas cold enough to support glaciers. U shaped valleys: they are the path of an alpine glacier. Glaciers carve out valleys with steep sides and flattish bottoms Cirques. A hollowed out basin where a glacier begins to form Arrrete: A ridge formed by cirques on either side of a rock mass Horn: a mountain with cirques on three or more sides. It looks kinda like a pyramid. The matterhorn in Switzerland is a great example morraine: A hilly ridge of material deposited by the glacier marking how far it advanced. A terminal morraine is the maximum advance of a glacier, a recessional morraine marks the advance of a glacier, but not the maximum advance. A lateral morraine is a morraine deposited on the side of a glacier. Erratic. A rock picked up and carried by a glacier and deposited elsewhere tarn: a lake that forms in a cirque fjord: A U shaped valley that is flooded by ocean water