Glacier Facts

Question 1

Warm-based glaciers

Answer 1

High altitude locations
Steep relief
Rapid rates of movement- 20-200m per year
Basal temps above pressure melting

Question 2

Cold-based glaciers

Answer 2

High latitude locations
Low relief
Basal temps below pressure melting point
Very slow rates of movement

Question 3

Factors influencing movement of glaciers

Answer 3

Gravity-fundamental cause of the movement of an ice mass
Gradient- the STEEPER the gradient of the ground surface the FASTER the ice will move
Internal temperature of ice - can allow MOVEMENTS of one are of the ice relative to another
Glacial budget- positive budget(net accumulation) causes glacier to ADVANCE
the thickness of the ice-influences Temp and PRESSURE MELTING POINT

Question 4

Two types of zones for movements glacier

Answer 4

Upper Zone- ice is brittle and breaks
Lower-zone under the pressure where the ice deforms

Question 5

Basal sliding

Answer 5

Warm based glaciers mainly move by basal sliding
If basal temp is ABOVE pressure melting a thin film of meltwater existed between Ice and the Valley floor and so FRICTION is REDUCED.

Question 6

Different ways Basal Sliding can occur

Answer 6

Slippage
Creep/regulation
Bed Deformation

Question 7

Different ways Basal Sliding can occur-Slippage

Answer 7

Where the ice SLIDES OVER VALLEY FLOOR as the meltwater has reduced FRICTION between BASE of the GLACIER and the VALLEY FLOOR

Question 8

Different ways Basal Sliding can occur-Creep/Regulation

Answer 8

When ice DEFORMS under PRESSURE due to OBSTRUCTIONS on the Valley Floor-causing ice to SPREAD around and OVER THE OBSTRUCTION

Question 9

Different ways Basal Sliding can occur-Bed Deformation

Answer 9

When Ice is carried by SATURATED BED SEDIMENTS moving beneath it on gentle gradients
Like ice being carried on ROLLER SKATES

Question 10

Internal deformation-

Answer 10

Cold based glaciers are unable to move by BASAL SLIDING-due to basal temps being below pressure melting point
They move by INTERNAL DEFORMATION

Question 11

Elements of Internal Deformation

Answer 11

Intergranular flow when individual Ice Crystals re-orientate and move in relation to each other

Laminar flow when there is movement of individual layers within the glacier

Question 12

Extending flow

Answer 12

Ice moves over a STEEP SLOPE unable to DEFORM quickly enough so it FRACTURES forming CREVASSES. The leading ice pulls away a from the ice behind it

Question 13

Compressing flow

Answer 13

When gradient reduce the ice thickens and the FOLLOWING ICE PUSHES OVER
The Slower-moving leading ICE

Question 14

Weathering

Answer 14

Influences the formation of glacial landforms. Uses heat energy to produce PHYSICALLY CHEMICALLY altered material ps

Question 15

Types of weathering-Physical

Answer 15

The breakdown of rock achieved by physical weathering processes that produce SMALLER FRAGMENTS of the Same Rock

Question 16

Types of Physical weathering

Answer 16

Freeze-thaw -water enters cracks/joints expands when freezes in CONFINED SPACES this exerts pressure causing Rock to SPLIT or PIECES BREAK OFF

Frost Shattering- Extreme Low Temps water trapped in ROCK PORES freezes and EXPANDS -causing Rock to DISINTEGRATE IN SMALL PARTICLES

Pressure Release- When weight of OVERLYING ICE in a glacier is lost due to MELTING the UNDERLYING ROCK EXPANDS and fractures PARALLEL to the surface .

Question 17

Chemical Weathering

Answer 17

Chemical reaction between the elements of the weather and some minerals within the rock
It produces weak residues of different material

Question 18

Chemical Weathering Processes 1

Answer 18

Oxidation-mineral in rocks REACTING with OXYGEN causing it to be SOLUBLE under extremely acidic conditions and original structure is DESTROYED

Carbonation- RAINWATER combines with dissolved CO2 from atmosphere to produce WEAK CARBONIC ACID , which reacts with CALCIUM CARBONATE in rocks to produce Calcium Carbonate which is soluble

Solution-Minerals DISSOLVING in water

Question 19

Chemical Weathering Processes 2

Answer 19

Hydrolosis- This is a Chemical Reaction between ROCK MINERALS + WATER

Hydration- Water molecules added to Rock Minerals creating new minerals of a Larger Volume

Question 20

Biological Weathering

Answer 20

Can consist of both physical actions and chemical processes

Question 21

Biological Weathering Processes

Answer 21

Organic Acids-produced during decomposition of plant and animal litter cause soil water to be more ACIDIC and react with some MINERALS known as CHELATION

Tree roots- GROW into CRACKS/JOINTS in Rocks and exert outward pressure