Formation of Landscape Features by Glaciers

Question 1

What is a cirque?

Answer 1

An amphitheatre-like valley formed by glacial erosion

Alternative names include corrie and cwm. The concave shape is open on the downhill side.

Question 2

Define a tor.

Answer 2

A large, free-standing rock outcrop that rises abruptly from surrounding slopes

Tors are usually no more than 15 meters high and are formed by freeze-thaw weathering or groundwater weathering.

Question 3

What are U-shaped valleys also known as?

Answer 3

Trough valleys or glacial troughs

Characterized by steep, straight sides and a flat or rounded bottom.

Question 4

What are hanging valleys?

Answer 4

Valleys found high on the sides of larger U-shaped valleys

They begin as corries and evolve into elongated corries or small U-shaped valleys due to erosion.

Question 5

What is an arête?

Answer 5

A narrow ridge of rock that separates two valleys

Formed when two glaciers erode parallel U-shaped valleys.

Question 6

What defines a horn or pyramidal peak?

Answer 6

A high triangular peak formed by three or more glaciers eroding toward each other

Question 7

What are glacial striations?

Answer 7

Scratches or gouges cut into bedrock by glacial abrasion

Question 8

What is a Roche moutonnée?

Answer 8

A rock formation created by the passage of a glacier

Features asymmetric erosional forms due to abrasion and plucking.

Question 9

Define moraines.

Answer 9

Accumulations of unconsolidated debris carried along by a glacier or ice sheet

Sometimes referred to as glacial till.

Question 10

What is an end/terminal moraine?

Answer 10

A moraine that forms at the terminal edge of a glacier, marking its maximum advance

Question 11

What is a recessional moraine?

Answer 11

A moraine left by a glacier during a temporary halt in its retreat

Question 12

What are lateral moraines?

Answer 12

Sharp-crested piles of debris dropped by melting ice, forming only in the ablation zone of a glacier

Question 13

What are medial moraines?

Answer 13

Moraines formed where two tributary glaciers converge

Question 14

What are ground moraines?

Answer 14

Sediments built up directly underneath a glacier, exposed when the glacier melts

Question 15

What is a kame?

Answer 15

An irregularly shaped hill or mound composed of sand, gravel, and till deposited by a retreating glacier

Question 16

Define drumlins.

Answer 16

Oval-shaped hills formed beneath a glacier, aligned in the direction of ice flow

Question 17

What are eskers?

Answer 17

Ridges made of sands and gravels deposited by glacial meltwater flowing through tunnels or channels

Question 18

What is an erratic?

Answer 18

A glacially deposited rock differing from native rock types in the area

Erratics can be carried over distances of hundreds of kilometers.

Question 19

What is a tarn?

Answer 19

A mountain lake formed in a cirque excavated by a glacier

A moraine may form a natural dam below a tarn.

Question 20

What are the Great Lakes?

Answer 20

A series of large interconnected freshwater lakes spanning the Canada–United States border

The five lakes are Superior, Michigan, Huron, Erie, and Ontario.

Question 21

Define the Finger Lakes.

Answer 21

A group of eleven long, narrow lakes located south of Lake Ontario

Question 22

What are kettles?

Answer 22

Depressions formed by retreating glaciers or draining floodwaters

Created by blocks of dead ice surrounded by sediment from meltwater streams.

Question 23

What are moraine-dammed lakes?

Answer 23

Lakes formed when terminal moraines prevent meltwater from leaving the valley

Question 24

What is a proglacial lake?

Answer 24

A lake formed by the damming action of a moraine during glacier retreat

Can also form from glacial ice dams or trapped meltwater.