Periglacial Environements Flashcards
What are periglacial environments?
Areas that are not glaciated but exposed to the extremely cold conditions
Location of periglacial environments
High altitudes and latitudes
What is the active layer?
A thin layer on top that thaws in winter and melts in summer, between 30-200 cm thick
What is permafrost like?
Contains varying amounts of ice which binds everything together. Can be up to 1500 cm thick and covers 25% of exposed land in the northern hemisphere e.g. Northern Russia tundra, Alaska and Canada.
Risks of permafrost
Causes change within ecosystems and infrastructure (roads and pipes) left vulnerable to erosion when melted. Thawing permafrost could possibly cause rock avalanches. Permafrost contains methane when frozen so after it melts it releases the greenhouse gas which contributes to climate change.
What is continuous permafrost?
Has no gaps
What is discontinuous permafrost?
Has gaps
What is sporadic permafrost?
Has pockets
What’s the active layer like?
Summer temperature is sufficient to melt the surface layer of permafrost, can be very mobile. Varies in thickness depending on latitude and vegetation cover
What is the talik?
Any unfrozen material within the permafrost zone
Periglacial environment example (Zugspite)
Highest peak of Wetter-stein and highest in Germany, Bavaria - Alps, northern edge. 2,962m above sea level, rock type = limestone, age of rock = Triassic rock
What is Scree?
Happens at the bottom of steep slopes where freeze-thaw occurs
What is Felsenmeer?
Exposed rock surfaces that have been broken by frost action. A covering of angular shattered rock on flat and high altitudes areas
What is solifluction?
The slow, downslope movement of fine, textured soils. The active layer thaws and excess water reduces friction so AL descends down the slope. Locate shaped debris masses form. Round features form terraces
What is a nunatak?
An exposed rock summit of a ridge (not covered by snow) which undergoes heavy freeze-thaw/frost shattering due to proximity of ice. Found in ice fields or glaciers