Landforms of glacial erosion - Striations

Question 1

What are striations?

Answer 1

Striations or striae, are marks on rock surfaces produced by rock particles embedded in ice.

Question 2

What do striations provide evidence of?

Answer 2

Striations provide evidence of abrasion and also indicate the direction of ice flow, with the deepest part of the striation at the initial point of impact.

Question 3

What does the deepest part of the striation mark?

Answer 3

The deepest part of the striation marks the initial point of impact.

Question 4

State the factors which control the type of striae?

Answer 4

Factors controlling the type of striae include: the size, shape and hardness of the rock used as an abrasive tool, the ability of the rock to remain in contact with the bed and the weight of the overlying ice.

Question 5

What do cross-cutting sets of striae provide evidence of?

Answer 5

Cross-cutting sets of striae provide evidence of the changing direction of glacier flow over time.

Question 6

What does small-scale plucking produce?

Answer 6

Small-scale plucking produces chatter marks and crescentic gouges align parallel with glacier flow.