Glaciers- Overview

Question 1

Mass Balance

Answer 1

This is the accumulation of snow fall measured against melting, evaporation or breakaway.

Question 2

When do glaciers form?

Answer 2

When accumulation exceeds ablation.

Question 3

What is required for formation?

Answer 3

Specific climate conditions

Question 4

What are the two zones of the glacier?

Answer 4

Ablation and Accumulation, seperated by an equilibirum line.

Question 5

What is the pathway of meltwater?

Answer 5

Deposits into sea, carving structures, depositing sands, silts and gravles.

Question 6

What are the ways glacial movement occurs?

Answer 6

Sliding, Ice Deformation and deformation of the glacial bed.

Question 7

What is rate of movement of a glacier dependent on?

Answer 7

Gravitational Forces
Resistance such as a drag of the bed

Question 8

What are examples of indications of glacial presence?

Answer 8

Corries, troughs, drumlins and moraines.

Question 9

What are the two major types of glaciers?

Answer 9

Ice Sheets
Ice Caps

Question 10

Ice Sheets

Answer 10

These are marked as ice domes exceeding 50,000km^2

Question 11

Ice Caps

Answer 11

High-latitude regions of a planet covered in ice.

Question 12

Ice Dome

Answer 12

Where mass is radially distributed outwards acting as dispsersal centres

Question 13

What are the two types of stream flow from a glacier?

Answer 13

Outlet Glaciers
Ice Streams

Question 14

Features of Outlet glaciers and Ice Streams?

Answer 14

Both rapidly moving, chanelled ice radiating from the interiors of the ice sheets.

Question 15

Outlet Glaciers

Answer 15

These occupy troughs of valleys being valley glaciers draining an inland sheet/cap flowing through a gap in peripheral mountians.

Question 16

Ice Streams

Answer 16

These occur within ice sheets responsible for discharge of most the ice and sediment within, flanked by slowly moving ice.

Question 17

What are the types of glacier based on topography?

Answer 17

Valley Glaciers
Transection Glaciers
Cirque Glaciers
Piedmont
Niche

Question 18

How do valley glaciers form?

Answer 18

Ice discharge from cirques or ice fields in a deep bedrock valley.

Question 19

Transection Glaciers

Answer 19

These are large networks of interconnected valley glaciers flowing in different directions

Question 20

How much of the Earth is covered in glacier?

Answer 20

16million km^2, 13.5 in Antarcitca and 1.74 in Greenland

Question 21

What does glacier distribution vary with?

Answer 21

Altitude, latitude, distance from precipitaiton and temperature changes

Question 22

Why do higher altitudes have more glaciers?

Answer 22

Temperatures decrease with air density

Question 23

Equilibirum Line Altitude

Answer 23

This is the region on the glacier where accumulation equals ablation.

Question 24

Why is slope aspect important in glacial formation?

Answer 24

Differenetial relief of solar radiation and precipitaiton.

Question 25

What is an example of a structure without capacity to accumulate snow?

Answer 25

A narrow summit with steep sides.

Question 26

How much ice cover in peak of quarternary glaciations?

Answer 26

30%

Question 27

What factors influence glaciation PERIODS?

Answer 27

Gradual increase in solar luminosity(4BYA was 75% present value

Question 28

Faint-Sun Paradox

Answer 28

The sun was younger with less luminosity yet the climate as warm as it is today

Question 29

Why has the planet remained relatively stable in temperatures?

Answer 29

GHG regulation by tectonic movement and silicate weathering

Question 30

Effects of silicates on temperature?

Answer 30

Burial, where upwelling results in release by volcanic outgassing

Question 31

How does topography regualte climate?

Answer 31

Mountain chains and continents influence ocean and atmospheric circulation

Question 32

What is the milankovitch cycle dependent on?

Answer 32

Eccentricity Obliquity Precession

Question 33

Eccentricity

Answer 33

This is deviation of Earths orbital path from the shape of a circle on 100,000 year cycles.

Question 34

Obliquity

Answer 34

This is the planets plane of orbit spinning on an axis on the angle between orbital plane and spin axis(41,000 year cycles)

Question 35

Precession

Answer 35

This is the change in orientation of rotational axis of a rotating body(23,000 year cycles)