AQA · A-Level · Geography

    Course version: 7037 · Version from Sept 2018

    Fluvioglacial processes: meltwater, erosion transportation and deposition.

    Full specification wording

    Systems and processes: Fluvioglacial processes: meltwater, erosion transportation and deposition.

    Fluvioglacial processes are driven by the immense power of glacial meltwater, shaping landscapes during deglaciation or seasonal melting.

    Checked against the AQA 7037 specification (opens in a new tab) on .

    • Point 5 of 6
    • 4 key terms

    Study notes

    From the checked teaching notes for this specification point.

    The idea

    Fluvioglacial processes are driven by the immense power of glacial meltwater, shaping landscapes during deglaciation or seasonal melting. Meltwater streams flow under high hydrostatic pressure within subglacial channels, giving them significant erosive power. Erosion occurs primarily through hydraulic action and abrasion of bedrock by a high suspended load. Meltwater transports vast quantities of sediment, rolling boulders via traction or carrying finer particles in suspension. As discharge decreases, the meltwater loses competence and capacity. This leads to the deposition of stratified, sorted, and rounded sediments, forming distinct fluvioglacial landforms such as eskers and outwash plains, contrasting with unsorted glacial till.

    What earns the marks

    • Explain the role of hydrostatic pressure in increasing the erosive power of subglacial meltwater streams.
    • Describe how fluvioglacial erosion occurs through hydraulic action, abrasion, and attrition.
    • Detail the transport mechanisms of meltwater, including traction, saltation, suspension, and solution.
    • Explain how a decrease in meltwater discharge leads to the deposition of sorted, stratified, and rounded sediments.

    Common mistakes and how to put them right

    • Confusing glacial till with fluvioglacial deposits.

      Put it right by stating that fluvioglacial deposits are sorted and stratified, whereas till is unsorted.

    • Assuming meltwater only flows on the surface.

      Put it right by explaining that subglacial and englacial channels carry significant volumes of meltwater under pressure.

    • Stating that meltwater erosion is identical to river erosion.

      Put it right by highlighting the role of high hydrostatic pressure in subglacial environments.

    Exam tips

    • Emphasise the seasonal and diurnal variations in meltwater discharge when explaining depositional processes.
    • Clearly distinguish between the characteristics of sediments deposited directly by ice and those deposited by meltwater.
    • Use the concepts of competence and capacity to explain why meltwater deposits sediment as its energy decreases.

    Try the lesson

    The start of the Systems and processes: Fluvioglacial processes: meltwater, erosion transportation and deposition. lesson, made from checked teaching notes for this specification point.

    Have a go first

    Which characteristic is typical of sediments deposited by fluvioglacial meltwater streams?

    Listen

    Fluvioglacial processes are driven by the immense power of glacial meltwater, shaping landscapes during deglaciation or seasonal melting. Meltwater streams flow under high hydrostatic pressure within subglacial channels, giving them significant erosive power. Erosion occurs primarily through hydraulic action and abrasion of bedrock by a high suspended load. Meltwater transports vast quantities of sediment, rolling boulders via traction or carrying finer particles in suspension. As discharge decreases, the meltwater loses competence and capacity. This leads to the deposition of stratified, sorted, and rounded sediments, forming distinct fluvioglacial landforms such as eskers and outwash plains, contrasting with unsorted glacial till. A strong answer earns marks for these points. Explain the role of hydrostatic pressure in increasing the erosive power of subglacial meltwater streams. Describe how fluvioglacial erosion occurs through hydraulic action, abrasion, and attrition. Detail the transport mechanisms of meltwater, including traction, saltation, suspension, and solution. Explain how a decrease in meltwater discharge leads to the deposition of sorted, stratified, and rounded sediments. A common slip: Confusing glacial till with fluvioglacial deposits. Instead, stating that fluvioglacial deposits are sorted and stratified, whereas till is unsorted. Exam tip: Emphasise the seasonal and diurnal variations in meltwater discharge when explaining depositional processes.

    See it

    A top-down flowchart. At the top, a node reads 'Meltwater under high hydrostatic pressure in subglacial channels'. Two arrows lead from it: one to 'Erosion: hydraulic action and abrasion of bedrock' and one to 'Transport: traction of boulders and suspension of finer particles'. From the erosion node an arrow leads to 'High suspended load', which then points to the transport node. From the transport node an arrow leads to 'Discharge decreases', then to 'Meltwater loses competence and capacity', then to 'Deposition of stratified, sorted and rounded sediments', and finally to 'Fluvioglacial landforms such as eskers and outwash plains'.
    It shows how pressurised meltwater erodes and transports sediment, and how falling discharge leads to deposition and fluvioglacial landforms.

    Key words

    Say what each word means before you turn the card.

    Meltwater dynamics

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    Fluvioglacial erosion

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    Sediment sorting and stratification

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    Hydrological processes in glaciated regions

    Try answering aloud or in your head before turning the card.

    See every definition
    Meltwater dynamics
    Meltwater streams flow under high hydrostatic pressure within subglacial channels, giving them significant erosive power.
    Fluvioglacial erosion
    Occurs primarily through hydraulic action and abrasion of bedrock by a high suspended load.
    Sediment sorting and stratification
    Deposition of stratified, sorted, and rounded sediments forms distinct fluvioglacial landforms, contrasting with unsorted glacial till.
    Hydrological processes in glaciated regions
    As discharge decreases, the meltwater loses competence and capacity, leading to deposition of sediment.

    Label the diagram

    Some boxes have lost their names. Pick the right name for each number.

    The diagram again, with 3 boxes numbered instead of named. A top-down flowchart. At the top, a node reads 'Meltwater under high hydrostatic pressure in subglacial channels'. Two arrows lead from it: one to 'Erosion: hydraulic action and abrasion of bedrock' and one to 'Transport: traction of boulders and suspension of finer particles'. From the erosion node an arrow leads to 'High suspended load', which then points to the transport node. From the transport node an arrow leads to 'Discharge decreases', then to 'Meltwater loses competence and capacity', then to 'Deposition of stratified, sorted and rounded sediments', and finally to 'Fluvioglacial landforms such as eskers and outwash plains'.

    • 1Box 1

    • 2Box 2

    • 3Box 3

    0 of 3 labelled

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