Periglacial processes and landforms

Created by: Junior
Created on: 04-05-13 13:29

What are perglacial areas?

cold areas that aren't covered in ice, temperatures mostly below freezing layer of permafrost on/bwloe surface, found at high latitudes, northern Asia, high altitudes, ice masses in mnt ranges, Tibetan plateau Asia, interior land masses Siberia

1 of 10

What is permafrost?

permanently frozen ground, top layer melts in summer (active layer) 20-25% of earths surface

2 of 10

Describe the different kinds of permafrost.

continuous - all ground is frozen, mean annual temperature below -5, discontinuous MAT below 0 for 2 years.sporadic permafrost

3 of 10

What is solifluction? and love formations.

permafrost is impermeable, Summer: active layer melts, layer becomes waterlogged and flows gradient.produces lobe formations, steeper gradient flow faster.

4 of 10

Describe the action of frost heave.

winter: active layer freeze create lens shape.fine grained soil(silt/clay) ice heaves up surface layers, occurs around stones heat loss faster than soil. lens stops stones sinking.

5 of 10

What kind of patterned ground is formed by frost activity?

corc;es, polygons or stripes. by frost heave and frost contraction. heave: stones upushed up and roll to edge of mounds forming circles, polygons when mounds close together, lines on a slope, contraction:ground crack in poly shape filled with stones

6 of 10

Explain the formation of Nivation hollows

Beginning of corrie, snow increase size of hollow, fluctuation of temp causes repeated freezing and thawing, ice expands frost shattering occurs, material washed away in summer.

7 of 10

What are Pingos?

ice-filled periglacial hills. conical hill with a core of ice. large as 80m and wide as 500m Kadleroshilik Pingo. alaska, largest in world

8 of 10

How are open system pingos formed?

discontinuous permafrost. groundwater forced up through gaps, water collects together and freezes, forming core of ice pushes ground above upwards.

9 of 10

How are closed-system pingos formed?

Continuous permafrost with lake at the surface, lake insulates ground, area beneath unfrozen, lake dries up and permafrost advances around unfrozen ground, water collects in centre, freezes creating core of ice, if core thaws, pingo collapses.

10 of 10

Other cards in this set

Card 2

Front

What is permafrost?

Back

permanently frozen ground, top layer melts in summer (active layer) 20-25% of earths surface

Card 3

Front

Describe the different kinds of permafrost.

Back

Card 4

Front

What is solifluction? and love formations.

Back

Card 5

Front

Describe the action of frost heave.

Back

View more cards

Get Revising

Periglacial processes and landforms