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Physical Factors Affecting Glaciers - Coggle Diagram
Physical Factors Affecting Glaciers
Lithology
The physical and chemical composition of rocks.
Clay:
has a weak lithology, little resistance to erosion, weathering or mass movement. Bonds that make up the rock are weak.
Basalt:
made of dense interlocking crystals, highly resistant, more likely to form prominent landforms e.g. aretes, pyramidal peaks.
Limestone:
composed mostly of calcium carbonate, soluble in weak acids to vulnerable to chemical weathering especially at low temps.
Structure
The properties of the individual rock types e.g jointing, bedding, faulting. Also includes the permeability of the rocks and the angle of dip pf rocks which can influence valley side profiles.
In
porous rocks
(e.g. chalk), pores separate mineral particles. The pores can absorb and store water - primary permeability.
Carboniferous limestone
is also permeable. Water seeps into joints which are then easily enlarged by solution - secondary permeability.
Horizontally bedded strata support steep cliffs with almost vertical profiles. Profiles tend to follow the angle of dip of the bedding planes.
Latitude and Altitude
Locations at high latitudes tend to have cold, dry climate with little seasonal variation in precipitation
Glaciated landscapes at high latitudes, tend to develop under the influence of large, relatively stable ice sheets e.g Greenland, Antarctica.
Glaciated landscapes at lower latitudes (but higher altitudes) develop under the influence of valley glaciers e.g. Rockies, Himalayas. They tend to have higher precipitation inputs but more variable temps so more summer melting.
Glaciers can still exist at a low altitude e.g. near the equator although they tend to be smaller and they go through more melting.
Relief and Aspect
Have an impact on microclimate and the movement of glaciers.
The steeper the relief of the landscape, the greater the resultant force of gravity and the more energy the glacier will have to move downslope.
If the aspect of a slope remains facing away from the sun, temps are likely to remain below 0ºc for longer. Less solar energy means less melting.
Aspect affects mass balance. glaciers with a +ve mass balance are likely to be larger with more erosive power and vice versa.
Climate
Wind is a moving force and is able to carry out erosion, transportation and deposition.
Precipitation is key in determining the mass balance of the glacier. In high latitude landscapes, this may be extremely low. In high altitude landscapes, this may be relatively high.
Precipitation is open to seasonal variation. The greater the variation, the more varied the mass balance will be.
If temperatures rise above 0ºc, accumulated snow and ice will start to melt and become an output of the system.
High altitude glaciers may experience significant periods in the summer months of melting whereas in high latitude locations, temps may never rise above 0ºc.