The Importance of a Glacier’s Front
A glacier’s front is the leading edge of the glacier where it meets the body of water into which it is terminally discharging (i.e. calving) icebergs. The importance of a glacier’s front cannot be overstated, as the front is what controls the rate at which a glacier melts and therefore its terminus position. A stationary front indicates that a glacier is not melting and is in equilibrium.
The Two Main Types of Glacier Movement
Glaciers move by a combination of sliding and flowing. Sliding occurs because the weight of the ice causes it to deform, just like plastic. The deformed ice actually flows very slowly, similar to honey flowing out of a container. Under most circumstances, the pressure melting point of ice is lower at the base of a glacier than it is at the surface, so glaciers melt at their base as they slide forward. This type of movement is called basal sliding. In some cases, however, the pressure melting point can be higher at the base than it is at the surface. This happens when there is a layer of material, such as water or mud, that allows the ice to slide easily over it.
Factors That Can Affect a Glacier’s Movement
Glaciers can flow like rivers, but the factors that affect their movement are very different. The speed of a glacier’s flow is determined by a number of conditions, including slope, ice thickness, and the amount of water at the base of the glacier. In addition to these physical conditions, the type of bedrock beneath the glacier can also affect its movement.
The Thickness of the Glacier
The thickness of a glacier can have a big effect on how quickly or slowly it moves. A thicker glacier will be more resistant to melting and will therefore move more slowly. A thinner glacier, on the other hand, will melt more quickly and therefore move more quickly. The thickness of a glacier can also affect how easily it flows. A thicker glacier will be more viscous and will flow less easily than a thinner one.
The Slope of the Glacier
One factor that commonly affects a glacier’s movement is the slope of the glacier. A shallower slope will cause a glacier to move more slowly than a steeper slope. This is because the force of gravity is not as strong on a shallower slope, so the glacier does not have as much “push” to move it along. Additionally, friction between the ice and the ground also plays a role in how quickly a glacier moves. A shallower slope means that there is less friction because there is less contact between the ice and the ground.
The Type of Material the Glacier is Made of
One of the primary factors that can affect a glacier’s movement is the type of material that the glacier is made of. If the glacier is made of tools, tools will cause resistance to the flow of the ice and may cause the ice to thicken and move more slowly. If the glacier is made of paper, it will be easier for the ice to slide over the ground and move more quickly. The type of material can also affect how sharp or blunt the leading edge of the glacier is.
How a Glacier’s Front Can Remain Stationary
A glacier’s front can remain stationary if there is a balance between the melting of ice at the front and the accumulation of snow further back. This can happen if the glacier is in an area with a lot of snowfall and little rainfall, or if the temperature is cold enough that the ice at the front does not melt.
If the Glacier is Thick Enough
A glacier’s front will remain stationary if the glacier is thick enough. The glacier must be thick enough to prevent water from eroding the base of the glacier and breaking it up.
If the Glacier is on a Steep Slope
A glacier’s front can remain stationary if it is on a steep slope. The reason for this is that the glacier’s weight is pressing down on the bedrock beneath it, holding it in place. The steeper the slope, the more pressure the glacier’s weight will exert, and the more likely it is that the glacier’s front will remain stationary.
If the Glacier is Made of the Right Type of Material
A glacier’s motion is determined by the type of material it is made of and the slope of the ground underneath it. On a steep slope, a glacier will flow quickly. On a gentle slope or level ground, it will flow more slowly or not at all. A glacier that contains a high percentage of fine particles will also flow more slowly than one with coarse material.