GL05 Factors affecting glacier movement Flashcards
What is the influence of climate on glacier movement?
A warmer climate leads to greater ablation and a decrease in mass balance, which can affect the speed of glacier movement.
What is substrate deformation?
Substrate deformation occurs when the sediment beneath a glacier deforms under the weight of the ice and moves under the pressure and friction of the ice.
What is the influence of altitude on glacier movement?
For every 100 meters of altitude gain, the temperature drops by 1°C, which can impact the temperature and pressure melting point at the base of the glacier.
What is extending and compressing flow?
As a glacier flows over a steep slope, it can stretch and fracture, forming crevasses, which is known as extending flow. As the gradient of the slope decreases, the ice thickens and compresses, closing the crevasses, which is known as compressing flow.
What are the factors that affect the speed of glacier movement?
Gravity, gradient, thickness of ice, internal ice temperature, and glacial budget (mass balance) are the five factors that can affect the speed of glacier movement.
How did the relief impact the speed of glacier movement in the Ascent of Everest?
The great Icefall presented a serious obstacle and constant source of danger, as the ice was always shifting downwards in sudden unpredictable surface changes. The Icefall led into a long narrow high-level valley, and as the glacier flowed over a steep slope, it stretched and fractured, forming crevasses, which is known as extending flow. As the gradient of the slope decreased, the ice thickened and compressed, closing the crevasses, which is known as compressing flow.
What is the relationship between melting and velocity in glaciers?
The seasonal differences in the amount of meltwater and the velocity of glaciers suggest that there is a positive relationship between melting and velocity, as the amount of meltwater increases, the velocity of the glacier increases.
Why is there a difference between summer and winter velocity in the Lirung Glacier?
During the summer, there is increased basal sliding due to the presence of meltwater, and during the winter, there is more internal deformation as there is less meltwater, and the ice is colder and more brittle.
Why do these patterns occur in the movement of glaciers?
These patterns occur due to the interaction of multiple factors such as temperature, mass balance, geology, and relief. The combined effects of these factors can cause differences in the speed and movement of glaciers.
How can climate affect the pressure melting point?
- Climate can affect the pressure melting point of ice in several ways. One of the most important factors is the amount of snowfall that occurs in a given region. In areas where there is more snowfall, the weight of the snow can compress the underlying ice, increasing the pressure and raising the pressure melting point. Conversely, in areas where there is less snowfall, the pressure on the ice will be lower, and the pressure melting point will be lower as well.
- Another way that climate can affect the pressure melting point of ice is through changes in temperature. As temperatures rise, the ice may start to melt, which can reduce the pressure on the remaining ice. This can in turn lower the pressure melting point, making it easier for the ice to melt.
What is the pressure melting point?
The pressure melting point is the temperature at which ice will melt under a certain amount of pressure. At lower pressures, the melting point of ice is lower than at higher pressures. This is because pressure can help to stabilize the structure of ice, making it more resistant to melting. Therefore, when the pressure is reduced, the melting point of ice decreases as well.
Is there more precipitation in warm-based glaciers or cold-based glaciers?
Warm-based glaciers tend to receive more precipitation than cold-based glaciers. This is because warm temperatures lead to increased evaporation and atmospheric moisture, which can result in greater precipitation in the form of rain or snow.
What is the inlfuence of latitude on glacier movement?
- Glaciers at lower latitudes, closer to the equator, generally receive more direct sunlight and experience warmer temperatures. This can cause the glacier ice to melt at a faster rate, leading to increased water flow and potentially more movement.
- Additionally, glaciers at lower latitudes may receive more precipitation in the form of rain, which can contribute to more meltwater and increased movement.
Do warm-based glaciers receive more snowfall than cold-based glaciers?
- No, warm-based glaciers typically receive more rainfall than snowfall, whereas cold-based glaciers tend to receive more snowfall than rainfall. This is because warm-based glaciers are located in regions with milder temperatures and higher snowlines, where snow is less likely to accumulate and remain on the glacier surface.
- In contrast, cold-based glaciers are typically located at higher latitudes and altitudes, where temperatures are much colder and snowfall is more common.
