Moraines

Question 1

What do end moraines mark?

Answer 1

The ice marginal position

Question 2

When the moraines are at the side of the glacier they’re called

Answer 2

lateral moraines.

Question 3

You can tell if a moraine has lots of ice in it because…

Answer 3

it’s covered in debris- ice is protected by debris so can last for a long time (can’t tell you of age therefore).

Question 4

Glacier advance

Answer 4

Positive mass balance

Can advance over previous moraines

Question 5

Glacier in balance

Answer 5

Glacier stay in one position and build up a large moraine

Question 6

Glacier retreat

Answer 6

Leave a series of moraines marking it’s retreat.

Question 7

End moraines general term for moraines that

Answer 7

Surround the glacier

Question 8

End moraines are formed by…

Answer 8

Melt (dump)
Freezing on
Push

Question 9

Melt-out Moraines

After a few years…

Answer 9

As a glacier melts out the debris will avalanche down the front, collecting, and forming an apron down the front (supra glacial source).
Subglacial/englacial source

they become vegetated and stablished- becomes harder for them to be washed away.

Question 10

Freezing on

Answer 10

Underlying sediments are freezed on.

In summer this will be melted out, forming a moraine.

Question 11

Push moraines

Answer 11

Another way in which moraines are formed is when there is some kind of subglacial source being pushed underneath towards the front, pushing up the sediment beneath it.
In this example the glacier is completely clean at the front (must have come from beneath).

Question 12

Glaciotectonics

Proglacial deformation

Answer 12

Deformation in front of glacier

Question 13

Compressed is…

Extended is…

Answer 13

Negative

Positive

Question 14

Styles of deformation

Answer 14

Open folding and nappes (ductile deformation)- where something is pushed and ‘bends’

Listric thrust faulting (brittle deformation)

Question 15

Faulting

Answer 15

Sometimes the sediment is too strong- instead of bending it snaps.

Question 16

Push Moraine formation

Answer 16

Bulldozed push moraines- frontal pushing

Deforming bed push moraines- frontal pushing + lateral stresses transmitted through the deforming mass

Question 17

Landsystems

Answer 17

Facies = individual sedimentary deposits

Facies assemblage/sediment landform association = facies laid down next to each other or in a vertical sequence

Landsystem = Large scale groupings of facies deposited in same environment plus erosional landforms from same time

Question 18

Hard bed rock glacier

Answer 18

Low debris supply- alpine

Question 19

High debris supply - Ghulkin-type

Answer 19

They have so much debris because of being formed in new tectonic areas
Big contrast in summer and winter temperatures
Can dam

Question 20

Soft bed rock glacier

Answer 20

Marginal ice sheet

Typically a series of push moraines, stagnant ice till underneath the glacier

Question 21

Push moraines are only formed by glaciers that…

Answer 21

have retreated and then advance again.

Question 22

The existence of a push moraine is usually evidence of…

Answer 22

the climate becoming poorer after a relatively warm period.

Question 23

Why are there characteristic differences in the orientation of rocks within a push moraine?

Answer 23

Material that had already been deposited is shoved up into a pile as the ice advances, and because most moraine material was deposited by falling down not pushing up, there are characteristic differences in the orientation of rocks within a push moraine.