Flashcards in Periglacial Landscape Deck (15)
What is a periglacial landscape?
Landscape that is exposed to cold conditions, with intense frost action and development of permanently frozen ground.
Examples of Periglacial Landscape?
Alaska, North Canada
Temps between -15 and -1
Annual Rainfall 120-1400mm
Short summers, long winters
Vegetation in the Tundra?
Pioneer species (low shrubs etc)
Difficult to grow due to harsh conditions
Ground hugging - to avoid harsh katabatibc winds
Shallow roots and waxy leaves to retain moisture
Example - Labradora Tea
Characteristics of Tundra soil?
waterlogged in summer, permafrost layer generally grey from iron (grey mud)
Characteristics of permafrost?
Permanently frozen ground.
Temperatures below 0 for 2 or more years
either continuous, discontinuous or sporadic
What is an Ice Wedge?
Relatively narrow cracks formed by ground contractions in upper layers of ground full with ice.
- cracks widens and deepens by expansion of ice
What Is a Solifluction Lobe?
Formed on a gradient, tongue shaped appearance that extends downslope.
- 50m wide
- 5m high
- small terrace can form on them
What is a Closed Pingo?
In areas of continuous permafrost. Develop beneath a lake bed, the permafrost lay of the lake bed remains frozen, rest may thaw. This means the lake may drain and water freezes. Expanding of ice forms a dome shape from the ice core.
Example - North Canada
What is an open Pingo?
In areas of discontinuous permafrost.
Valley bottom, water seeps to upper layers due to artesian pressure, water will freeze and the ice core will expand to form a bingo shape.
Example - Alaska
What is a Thermokarst?
Depressions in the ground surface from ice melting within permafrost, this can cause subsidence.
What is a Terracette?
Pathways running horizontally along a slope. Formed by Frost Action and Soil Creep
What is Patterned Ground?
Ice lens grows in autumn as active layer freezes and thaws daily. Ice lens grows, pushing sediment above it, creating stone rings as larger sediment falls to edges.