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

Glacial landforms.

Extracts from this document...

Introduction

a) Outline the possible sources of glacial till. As it melts, ice deposits the material it has transported. Such debris varies greatly in size and composition and, in contrast to fluvial deposits, is unsorted as it is all collected from the bottom or sides of the rocks through the process of abrasion. Meltwater will transport ice-deposited debris further and produce fluvioglacial deposits of sorted material. The term drift includes both glacial and fluvioglacial deposits. Glacial deposits are termed till. Lodgement till is laid down beneath moving ice and ablation till beneath relatively static, melting ice. b) Examine the field evidence that could be used to distinguish between landforms of glacial and fluvioglacial deposition. Fluvioglacial deposits are likely to be more rounded than glacial deposits because of the processes of attrition that occurs during water transport. They are also likely to be sorted into layers because as the discharge of meltwater streams drops, large load items will be deposited; medium sized items will be deposited when discharge falls further, and finally small items will be deposited. ...read more.

Middle

Or it may be the result of deformation of subglacial ice producing areas of lower pressure that allows till accumulation. Drumlins are often found at confluence of tributary glaciers and where glaciers spread out into plains. Crag and tail are where resistant outcrops of rocks project into the base of the glacier, deposition may occur in the zone of lower pressure downstream of obstruction. This is streamlined by glacier movement to produce a tail for the crag. So these are the features and landforms that will distinguish them from fluvioglacial landforms. These landforms will be much rougher, not very rounded, and will not be sorted into different layers, unlike fluvioglacial landforms. Fluvioglacial deposits are sorted vertically and horizontally and consist of particles that are more rounded than glacial deposits. Material is deposited by meltwater because of a loss of energy, for example when water enters a lake or when there is a sudden drop in discharge. The most important features formed by fluvioglacial erosion are meltwater channels. Such channels may be proglacial, marginal, subglacial or overflow channels. ...read more.

Conclusion

Kame terrace's that are deposited by meltwater between unglaciated higher ground and edge of ice sheet. Kame delta's, delta built into a proglacial lake. Varves are alternate layers of silt and sand deposited in fluvioglacial lakes, the coarser, lighter coloured sand is deposited in spring when meltwater stream discharge is high and load is carried at its maximum. The darker silk sized sediments are deposited in the autumn, and discharge levels are lower, and only small particles can be transported. Kettles are blocks of ice that become detached from a retreating glacier, and will be partially buried by fluvioglacial deposits. When the ice melts, its form of depression will fill with meltwater. Braided streams are fluvioglacial streams that exhibit a high degree of braiding, as seasonal fluctuations in discharge produce periods of depression. To answer the question, the field evidence that would be examined would firstly be the shape of the landform and whether it was rounded or not. Secondly whether the material was sorted or not would give a clear indication as to whether it was glacially deposited or fluvioglacialy deposited. Also, it would seem appropriate to suggest that landforms that are located near lakes or other water features would be formed by fluvioglacial depositions. ...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

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. Hydrology and Fluvial geomorphology. (Q&A)

    Storm run-off is the extra volume of water that reaches a river quickly as the ground cannot absorb it. This is what can cause a river to flood. There is more information about flood hydrographs page , Q: Why in a storm hydrograph there is a lag time between the peak rainfall and the peak discharge.

  2. Fluvioglacial Landforms

    When the water level rose it spilled through a low col eroding a deep gorge in the landscape. Also occurring in areas which experience fluvioglacial erosion are Sichelwannens and Tunnel Valleys. Sichelwannens are crescent shaped scour marks made from malt water stream sometimes flowing supraglacially on the edge of a glacier.

  1. To what extent are fluvio-glacial deposits and landforms distinctive?

    There are two main types of glacial erosion; Plucking and Abrasion. Plucking occurs when sub-glacial melt-water enters weaknesses in the rock, mostly on the valley floors, and the water then re-freezes and attaches itself to the ice above (on the actual glacier).

  2. fluvioglacial and glacial variations

    Eventually the material deposited will become a mound. This mound will have layers of moraine as the flow of melt water varies on a daily and seasonal basis, different types of material will be carried by varied volumes of water. Drumlins, however, are formed by the glacier itself.

  1. Main features and landforms of glacial erosion.

    Their cross sections are often semicircular to parabolic, and their walls are commonly striated. MESO-SCALE: Whalebacks: Rock drumlins and streamlined spurs; these are smoothed areas of bedrock, attributed to unconfined glacier slip across the bedrock surface. They have a characteristic domed shape, and their long axes tend to be aligned parallel to ice flown direction.

  2. Do the Characteristics of a river change downstream?

    lined up a bubble inside the spirit level within the device by using a rotating grip. Once the bubble had been lined up, the angle at which the land was slanted was shown on the side of the abney level.

  1. Free essay

    Movement of Ice Sheets during the last glacial advance in the UK

    The weight of the glacial ice caused a rotational movement allowing the ice to move through the hollow, enlarging it further to form a true cirque. The movement of the glacial ice allows plucking to occur which steepens the back wall and also allows debris to be collected in the base of the glacial ice.

  2. The Afon Glaslyn, SnowdoniaCase Study of fluvial landforms and processes

    As well as erosion transportation also occurs - the load is made up of large boulders sand and clay.Therefore it is mainly traction and saltation taking place- rolling stones across bed and sand size+particles bouncing along bed. As the sediment is large has not been eroded yet there is little suspension (clay sized particles carried with flow)

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