Glaciated Landscapes and Change Flashcards
Define a glacial period
A period of colder temperatures
Define an interglacial period
A period of warmer temperatures
Identify one long term cause of glacial periods
The Milankovitch Cycle
What are the 3 elements of the Milankovitch cycle?
- Eccentricity
- Tilt
- Wobble/Axial Precession
What is eccentricity?
When the Earth’s orbit changes from circular to eclipse/elongated
What is tilt? [2]
-The Earth’s tilt changes between 21.8 and 24.4 degrees.
-The greater the tilt, the more solar energy the poles receive
What is wobble/axial precession? [2]
-Over time, the direction in which the axis tilts changes
-This does not affect how much sun the Earth’s receive overall, only where the solar radiation is distributed
Identify the short term causes of glacial periods [2]
-Asteroid Strikes
-Volcanic Eruptions
What are sunspots?
Sunspots are temporary spots on the Sun, that send more solar radiation towards the Earth
What are the climate characteristics in polar regions? [2]
-Little rainfall
-Little wildlife
What are the vegetation and soil characteristics in polar regions?
-Only highly adapted vegetation can grow
-Slow nutrient cycles, meaning the soil is usually deprived of nutrients
What are alpine environments?
Areas of low temperatures in high altitude, mountainous regions
What are periglacial landscapes? [2]
-Areas found on the edge of colder environments
-These areas have permanently frozen ground (permafrost)
What are the 3 types of permafrost?
Continuous, Discontinuous and Sporadic
What do the 3 types of permafrost indicate?
The extent of the permafrost cover
What are the climate, vegetation and soil characteristics of periglacial environments?
-Similar to polar environments
What are the 4 periglacial processes?
Nivation, Active Layer, Frost Heave and Solifluction
Explain the term nivation
-It’s a collective term for processes involving snow and ice that cause erosion
What is the active layer?
The top layer of permafrost that thaws in the summer
What is frost heave? [3]
-Upward swelling of soil due to the formation of ice during freezing conditions.
-The freezing temperature penetrates the soil and turns the present moisture into ice
-Generating an upward movement in the soil.
Explain how solifluction lobes are formed
- The active layer thaws in warmer temperatures
- This turns the ice to water, which lubricates the surface
- This reduces friction between the particles, leading to them falling downslope
Define accumulation
The addition of mass to the glacier
Define ablation
The loss of mass from the glacier
Define glacial budget
The mass of the glacier, the difference between accumulation and ablation
What does a positive glacial budget mean?
Accumulation exceeds ablation, so the glacier is advancing
What does a negative glacial budget mean?
Ablation exceeds accumulation, so the glacier is retreating
What is an input?
An addition to the glacier e.g. snow
What is an output?
Things that leave the glacier e.g. meltwater
Explain the term energy [2]
-Glacial energy is usually in the form of kinetic energy as the glacier moves
-This energy allows erosion to occur
Define a store
The mass that glaciers hold
What are the 3 types of stores
Subglacial, Englacial and Supraglacial
What does subglacial mean?
Underneath the glacier
What does englacial mean?
Within the glacier
What does supraglacial mean?
On top of the glacier
What is an example of a “flow”
Compressional Flow
What is the equilibrium line?
The area where mass gain = mass loss
What is a feedback loop?
A type of chain reaction, where one process leads to another process