periglacial environments

Question 1

what is Solifluction?
what landforms does it produce?

Answer 1

• The downward movement of the waterlogged the active layer due to the influence of gravity
• forms solifluction lobes

Question 2

what are Solifluction Lobes

Answer 2

• a landform created when the soil falls down the hillside in tongue-shaped lobes.

Question 3

what is nivation?
what landforms are produced by this?

Answer 3

• a combination of erosional and weathering processes due to snow and ice
• forms nivation hollows

Question 4

what is the active layer?

Answer 4

•the surface of the ground, which is able to move because it has been thawed

Question 5

what is permafrost?
and what are the three types?

Answer 5

•ground that has been permanently frozen for over two years

•there is continuous, discontinuous and sporadic permafrost

Question 6

what is continuous permafrost ?
where is it found?

Answer 6

• permafrost that is very deep (up to 1500m deep in some cases) and has summers so cold that there is only very little surface melting
• found at the highest latitudes where almost all ground is frozen at a great depth

Question 7

• what is discontinuous permafrost

Answer 7

• when the permafrost is relatively shallow and has parts of unfrozen ground
• occurs in areas with a mean annual temperature of -5°c and -1.5°c.
• the surface of discontinuous permafrost tends to melt over the summer months

Question 8

what is sporadic permafrost ?

Answer 8

• permafrost found where the mean annual temperature is just below 0°c, and permafrost patches cover less than 50% of the landscape

Question 9

what’s frost heave?
how does it happen?
what landforms does it create?

Answer 9

• Frost heave occurs when soil expands and rises due to the freezing of water within it.
•When the temperature drops, water in the soil freezes, creating ice lenses that force the soil upward.
• creates patterned ground and pingos. overtime frost heave is repeated which creates hills, or patterns where the soil has been forced out over the ice in the soil.

Question 10

what’s frost action?

Answer 10

• any process that occurs in soil and rock due to the freezing and thawing of water eg frost heave

Question 11

what’s meltwater erosion?
what features does it create?

Answer 11

• is the process by which water from melting snow or ice erodes the streams or river channels
• This can create features like valleys and braided rivers

Question 12

what do high winds do to the periglacial environment?

Answer 12

• they can cause erosion by removing loose soil and sediment,
• it can also transport fine particles and dust, reshaping the landscape
• they can contribute to the formation of features like patterned ground by aiding in the movement of stones and soil.

Question 13

how do ice wedges form?

Answer 13

• through freeze-thaw cycling.
•when it’s cold, water in the cracks of soil or permafrost freeze, and cracks widen. When temperatures rise again, the ice melts but the cracks remain. this process repeats and more water can enter the cracks and freeze, leading to the growth of the ice wedge.

Question 14

what is a loess?
how does loess form?

Answer 14

• it’s a type of sediment that is made up of fine silt and dust particles.
• Loess forms when a glacier grinds the bedrock turning it into rock flour, and this sediment travels to the snout of the glacier in meltwater or through the wind.

Question 15

how does patterned ground form ?

Answer 15

• When the ground repeatedly freezes and thaws, ice in the soil forces upwards rock and sediment creating cracks and patterns on the surface of the rock. These patterns can take various shapes,

Question 16

how does a closed system pingos form?
how does it differ to an open system pingo?

Answer 16

• it forms when there is a layer of permafrost that has groundwater beneath it or on its surface. As the groundwater freezes, it expands and pushes the overlying soil upward, creating a dome shape.
• sometimes in summer, the ice lens can melt and the pingo will collapse, creating a hollow (ognip)

• one diff is they typically form in continuous permafrost areas
• the groundwater supply is not continuous

Question 17

where are periglacial area found today vs the past ?
and why is that the case?

Answer 17

• today periglacial areas are found at higher latitude, and some alpine areas (lower latitudes with higher altitudes)
• during the pleistocene epoch, periglacial areas were found in todays mid-latitude ; temperate areas
• there are less periglacial areas now due to global warming which has led to the melting of ice, so less land is in close proximity with glacial areas

Question 18

what are stone polygons?
how do they form?

Answer 18

• they are stones that are arranged in a polygonal pattern on the ground.
• they form when ice expands during freezing, which pushes stones to the surface through frost heave , creating patterns

Question 19

what is calving?

Answer 19

• the process where chunks of ice break off from the edge of a glacier into the a body of water , forming icebergs.

Question 20

what is ground ice ?

Answer 20

• ice that forms within the soil or sediment, often in permafrost regions.

Question 21

what are braided rivers?
how do they form?

Answer 21

• a type of river that has multiple channels that weave in and out around small islands or bars of sediment.
• formed when the a meltwater stream or river has a high sediment load and due to changes in water volume or energy, the sediment is deposited causing the river to find an easier course around the sediment

Question 22

what is a talik?
what type of permafrost is it found in?

Answer 22

• a layer of unfrozen ground that exists under or on top of a layer of permafrost.
• found in discontinuous permafrost

Question 23

what is a thaw lake?

Answer 23

• a lake that forms in permafrost regions when the ground thaws during warmer seasons and water fills in depressions in the landscape

Question 24

what are periglacial environments

Answer 24

• places that are on the fringe of glacial landscapes and have periods of extremely cold temperatures and the presence of permafrost

Question 25

what is isolated permafrost?

Answer 25

• permafrost that covers less than 10% of an area

Question 26

what is freeze thaw weathering / frost shattering?
what landforms does it form?

Answer 26

• when water gets into the cracks of rock, and freezes when the temperature drops, causing it to expand by around 10% , expanding cracks in the rock
• it forms felsenmeer (when on a flat surface) which is an accumulation of angular rock fragments, or forms scree when it’s on a slope

Question 27

what is groundwater freezing?
what features does it produce?

Answer 27

• when water in the ground or soil turns into ice.
• creates ice lenses and permafrost

Question 28

what is aeolian action?
what landforms does it form?

Answer 28

• the processes of erosion, transportation, and deposition of sediment by wind.
• it can create dunes & loess deposits,

Question 29

how do open system pingos form?
how do they differ from closed system pingos ?

Answer 29

• they form when groundwater flows through gaps in the permafrost causing water to accumulate and freeze, creating an ice lens
• the active layer surrounds the ice lens and forms a dome shaped hill
The key difference is that closed system pingos rely on trapped groundwater,
• one diff is that open system pingos depend on an external supply of water.
• open system pingos are typically found in discontinuous permafrost