• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Examine the factors influencing the movement of glaciers.

Extracts from this document...

Introduction

Examine the factors influencing the movement of glaciers. Glacier is defined as, 'a mass or river of ice moving very slowly'. Glaciers range in size considerably, Antarctica being the largest ice mass at 12.5 million km and a smaller ice mass of 12km existing in Africa. Glaciers move due to the force of gravity from areas of high altitude to lower areas. There are different mechanisms of glacial movement depending on the type of glacier. Cold (polar) glaciers are frozen to the underlying rock surface. These are found in high-latitude locations where the relief is low and basal temperatures are below the pressure melting point. Cold glaciers have very slow rates of movement, e.g. The Meserve glacier in Antarctica moves only 3-4 metres per year. Warm (temperate) glaciers on the other hand are not frozen to their bed. This type of glacier is found in high-altitude locations where the relief is steep and basal temperatures are at or near the pressure melting point. ...read more.

Middle

Basal sliding involves a combination of mechanisms. Slippage is where the ice slides over the valley floor as described above. Creep is affected by the surface over which the glacier slides. If there is an obstacle in the glaciers path, pressure increases and enables it to move as a plastic, either around or over the obstacle. When the pressure is reduced, the glacier then re-freezes. The lower the temperature, the greater the pressure needed to allow this mechanism to take place, which is why it is less likely to occur in cold glaciers. Bed deformation is another mechanism involved in basal sliding. This is when the ice is carried by saturated bed sediments moving beneath it. The factor influencing this is therefore the sediment on the surface over which the glacier moves and the pressure which it imposes on the glacier. Polar glaciers cannot move by basal sliding as their temperature is below the pressure melting point. ...read more.

Conclusion

Occasionally some glaciers may surge forward about 100m per day. Factors influencing this movement are a steep gradient and a large input such as a snowfall. This is only likely to occur in temperate glaciers where the basal temperature is relatively high and the ice mass is not frozen to the underlying rock. In conclusion, the velocity of ice flow varies considerably, depending on factors such as the thickness of the ice, the surface over which the glacier is advancing and the amount of meltwater available to lubricate the base of the glacier. Some glaciers creep so slowly that their movement can only be seen over a period of years, whereas other advance at several metres per day. Different factors influence the movement of glaciers depending on the basal temperature of the glacier as this determines the mechanism by which the glacier will move. Glaciers move most rapidly when the gradient is steep, when the ice is fairly thick and when basal temperatures are at or above the pressure melting point. Emma Alexander U63 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Hydrology & Fluvial Geomorphology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

A very good answer using a lot of key geographical terminology. The answer would be strengthened considerably by incorporating specific examples.
4 stars

Marked by teacher Molly Reynolds 07/08/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Hydrology & Fluvial Geomorphology essays

  1. Marked by a teacher

    Analyse How the Inputs and Outputs from a River Basin Can Vary Over Time

    3 star(s)

    For example the smaller amount of precipitation a catchment area receives, the less input to the river basin. The wind patterns would determine the positioning of clouds and the possibility of relief rainfall. The size, shape and relief of a river basin also has a role in a rivers discharge,

  2. Hydrology and Fluvial geomorphology. (Q&A)

    It is calculated by multiplying the cross-sectional area by the mean velocity (speed). A river's regime is based on average monthly discharge figures. These are collected over at least 20 years to try to eliminate minor year-to-year variations. There are several factors which will affect the river's regime, including rainfall, temperature, human use of the land and the landscape.

  1. Explain how human activity can modify the hydrological cycle.

    It also takes the water from the water cycle. The water may then enter a human drain as it is sued which will move it quickly to a river or a lake. There is therefore less water being stored in the water table and the water is then moved to

  2. 'To what extent does the River Lyn conform to the Bradshaw model of River ...

    � wetted perimeter (m) 11/11/02 23 Discharge Ruler Pencil Primary data To see if it conforms to the Bradshaw model By doing the calculation velocity x cross-sectional area. 11/11/02 11, 12, 13, Photographic evidence Camera To have visual evidence as well as written evidence.

  1. The Amazon River: Case Study

    The Amazon proper is navigable to ocean liners of virtually any tonnage for two-thirds of its course. Transatlantic ships call regularly at Manaus, nearly 1600 km upstream; and smaller ships can reach Iquitos, Peru, 3700 km from the river's mouth, the farthest point from sea of any port serving ocean traffic.

  2. Study the river Cray and see whether the river actually follows a natural path ...

    Attrition is the knocking of rock fragments in the water against one another. The fragments are broken into smaller pieces and become smoother along the process. Corrosion, also known as corrosion, is the process by which river water reacts chemically with soluble minerals in the rocks and dissolves them.

  1. I am going to study the characteristics of rivers and how they change as ...

    Firstly, the cross-sectional area is to be found. Secondly, the velocity of the river has to be found in metres per second. So the discharge is then found by multiplying the cross-sectional area and the velocity of the river. A metre ruler will be held on the river.

  2. Examine how a glacier operates as a system (25)

    The rate of formation varies with area and temperature. In Iceland, a warm based glacier, for example where there?s plenty of snow and warmer summers to produce the necessary meltwater, glaciers can form in about 10 years but in Antarctica, a cold based glacier, where there?s little snowfall and it?s too cold to produce meltwater, glaciers can take centuries to form.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work