1. how can glaciated landscapes be viewed as systems? - spec

inputs to a glaciated landscape system

• Snow accumulation – The primary input; fresh snow undergoes compression over time, becoming firn and eventually glacial ice.

• Precipitation – Besides snowfall, rain and hail can contribute to glacier mass when frozen.

• Rock debris – Carried onto glaciers from valley walls via weathering and erosion. These fragments later play a key role in shaping landscapes.

• Solar energy – Radiation from the sun affects ice melting, influencing glacier mass balance.

• Gravity – The driving force pulling ice downhill, aiding movement through basal slip or plastic flow.

• Meltwater – Acts as a lubricant, increasing the rate of ice movement. It may also contribute to erosion through glacial meltwater channels.

• Wind-blown sediments – Fine particles may accumulate on ice surfaces, influencing albedo and melting.

processes of a glaciated landscape system

• Accumulation – When the rate of snow and ice input exceeds mass loss, leading to glacier advance.

• Ablation – The opposite of accumulation; ice loss through melting, evaporation, or sublimation leads to glacier retreat.

• Dynamic Equilibrium – A system maintains balance through self-regulation; when a glacier undergoes temporary imbalance, it adjusts naturally.

• Basal slip – Meltwater lubricates the base of the glacier, allowing it to slide over bedrock.

• Plastic flow – Ice behaves like a plastic under pressure, deforming internally to enable movement.

• Regelation – Ice melts due to increased pressure on the upstream side of an obstacle, flows around it, then refreezes.

• Extending and compressing flow – Ice responds to changes in gradient:

  • Extending flow: Ice speeds up over steeper terrain, becoming thinner and forming crevasses.

  • Compressing flow: Ice slows down over gentler slopes, thickening due to reduced velocity.

• Surges – Some glaciers experience temporary rapid movement, dramatically reshaping landscapes.

• Glacial erosion processes:

  • Abrasion: Rock debris within ice grinds against bedrock, smoothing surfaces.

  • Plucking: Ice freezes onto rock and pulls fragments away as the glacier moves.

  • Freeze-thaw weathering: Water enters cracks in rock, freezes, expands, and breaks it apart.

• Glacial transportation and deposition – Glaciers transport rock debris, depositing it as moraines when melting.

outputs of a glaciated landscape system

• Ablation – Loss of glacier mass through melting, evaporation, and sublimation.

• Rock debris deposition – Glaciers leave behind sediments, forming distinctive landforms like moraines, drumlins, and erratics.

• Meltwater streams – Carry sediment (rock flour), creating milky-colored glacial rivers.

• Glacial retreat – As ablation exceeds accumulation, glaciers shrink, altering landscapes.

• Energy loss – Solar energy is reflected, absorbed, or re-radiated, affecting melting rates.

flows of energy through glaciated systems

• Solar radiation – Controls melting, evaporation, sublimation, and influences snow albedo.

• Kinetic energy – Movement of ice results in erosion and landscape modification.

• Thermal energy – Heat influences melting, affecting glacier behavior.

• Potential energy – Stored in accumulated ice; when released, gravity drives movement. - the taller the glacier, the more gpe it has

• Geothermal heat – From the Earth's crust, it may contribute to basal melting under certain conditions.

flows of material through glaciated systems

• Rock debris transport – Sediments are carried within, on top, and beneath the glacier.

• Meltwater flow – Streams originating from glaciers redistribute sediments across landscapes.

• Sediment deposition – Creates moraines, drumlins, and glacial lakes.

• Ice movement – Facilitates erosion and the transport of material over vast distances.

glacier mass balance

The glacier mass balance or budget, is the difference between the amount of snow and ice accumulation and the amount of ablation occurring in a glacier over a one year period.

The annual budget of a glacier can be calculated as follows:

total accumulation-total ablation

prone to temporal (seasonal variations)

• in high latitude glaciers in winter accumulation>ablation

• in summer ablation>accumulation

• due to seasons, budget varies in a yeear

• high altitude/low lat glaciers = less variation, less seasons, accumulation and ablation happens at the same time as more tropical regions closer to the equator.

dynamic equilibrium

How Dynamic Equilibrium Works in Glaciated Landscapes

• Inputs > Outputs (Accumulation Phase) – If snowfall and ice accumulation exceed melting and evaporation, the glacier advances.

• Inputs < Outputs (Ablation Phase) – If melting and sublimation exceed accumulation, the glacier retreats.

• Self-Regulation – The glacier reacts to disturbances by adjusting mass balance, attempting to restore equilibrium.

how climate influences a glaciated landscape system

• Wind is a moving force and as such is able to carry out erosion, transportation and deposition. These aeolian processes contribute to the shaping of glacial landscapes - particularly by acting upon fine material previously deposited by ice or melting.

• Precipitation totals and patterns are key in determining the mass balance of a glacier as precipitation provides the main inputs for of snow, sleet and rain
  
  - In high latitude areas precipitation totals may be very low whereas in high altitude locations they may be a lot higher.
  
  - Also significant seasonal variation with rates of precipitation, more varied precipitation the more varied the mass balance of the glacier will be.

• Significant factor
  
  - If temp rises above 0 degrees, accumulated snow and ice will begin to melt and become an output of the system
  
  - High altitude areas may experience significant periods in the summer months of above 0 temps and melting
  
  - High latitude areas temps may never rise above 0 and therefore means that no melting occurs - explains why ice sheets are so thick in polar regions, despite low precipitation inputs

• Antarctic Ice Sheet – Despite low annual precipitation, glaciers remain due to consistent sub-zero temperatures preventing melting.

• The Alps, Europe – Seasonal precipitation variation leads to mass balance fluctuations, affecting glacial advance and retreat.

how geology influences a glaciated landscape system

1. Rock Types and Their Resistance

• Weak Lithology: Rocks like clay have weak bonds between particles, making them highly susceptible to erosion and deformation.

• Resistant Lithology: Basalt, composed of dense interlocking crystals, is highly resistant and forms prominent glacial landforms such as arêtes and pyramidal peaks.

• Soluble Lithology: Limestone, made of calcium carbonate, is vulnerable to decay through chemical weathering (carbonation), especially in colder climates.

Place-Specific Example – The Lake District, UK

• Scafell Pike (England’s highest peak) is composed of volcanic rock (andesite and basalt), making it resistant to glacial erosion. This has allowed the formation of sharp peaks and deep valleys.

• Helvellyn Ridge has notable arêtes and corries, formed by glaciers eroding along rock weaknesses.

• Malham Cove (Yorkshire Dales) is an example of a limestone landscape, where carbonation has shaped cliffs and underground drainage systems.

Rock Structure and Its Impact on Glaciated Landscapes

The structure of rocks (jointing, bedding, faulting) affects permeability and erosion:

2. Types of Permeability

• Primary Permeability: Found in porous rocks like chalk, where tiny air spaces allow water absorption and storage.

• Secondary Permeability: Seen in Carboniferous limestone, where water seeps into joints that are widened by solution, forming features like caves and limestone pavements.

Place-Specific Example – The Yorkshire Dales, UK

• Gordale Scar and Malham Tarn result from water flowing through limestone (secondary permeability), creating unique karst landscapes.

• Pen-y-ghent exhibits steep cliffs formed by horizontally bedded Carboniferous limestone.

3. Structural Influence on Valley Profiles

The angle of dip of rock layers strongly influences glacial valley formation:

• Horizontally bedded strata create steep cliffs with near-vertical profiles.

• Inclined strata create valley profiles that mirror the dip of bedding planes.

Place-Specific Example – The Cairngorms, Scotland

• The Lairig Ghru glacial valley follows the natural dip of rock strata, displaying a classic U-shaped valley due to glacial erosion.

• The Devil’s Point and Braeriach Peaks are shaped by resistant rocks (granite) that have withstood extensive erosion.

how latitude and altitude influenced a glaciated landscape system

High-Latitude Glaciated Landscapes

• Located closer to the poles, typically beyond 66° N/S.

• Cold, dry climates with little seasonal temperature variation.

• Dominated by large, stable ice sheets that persist due to low annual melting.

Place-Specific Example – Antarctic Ice Sheet

• The East Antarctic Ice Sheet is the largest and most stable ice mass on Earth.

• Minimal melting occurs due to continuous sub-zero temperatures, despite low precipitation.

• Ice depth exceeds 4 km, yet accumulation rates are very slow due to dry conditions.

High-Altitude Glaciated Landscapes

• Found in mountainous regions, even at lower latitudes.

• Greater precipitation input and seasonal temperature variation, causing summer melting.

• Glaciers form under the influence of dynamic valley glaciers rather than vast ice sheets.

Place-Specific Example – The Andes Mountains

• Despite being near the equator, glaciers exist due to high-altitude cooling (approx. 0.6°C decrease per 100m).

• Quelccaya Ice Cap, Peru – One of the world’s largest tropical glaciers, heavily dependent on annual snowfall.

• Summer melting leads to significant glacier retreat, making it highly vulnerable to climate change.

releif and aspect on microclimate and glacier movement influences a glaciated landscape system

Aspect – The Direction a Slope Faces

• Slopes facing away from the sun receive less solar energy, maintaining sub-zero temperatures for longer.

• These areas retain ice, leading to positive mass balance, encouraging glacier advance.

• Slopes facing towards the sun experience more melting, resulting in negative mass balance and glacier retreat.

• Influence on erosion: Larger glaciers with positive mass balance erode more intensely, shaping deep valleys and sharp ridges.

Aspect – Influence on Glacier Behavior in Alaska

• North-facing glaciers in Brooks Range receive less sunlight, keeping them colder and more stable.

• South-facing glaciers, like Matanuska Glacier, get more solar energy, leading to faster melting and retreat.

• Juneau Icefield shows noticeable differences—north-facing glaciers remain more stable, while south-facing ones retreat faster due to higher solar exposure.

Relief – Impact on Glacier Energy and Movement

• Steeper landscapes increase gravitational force, leading to higher glacier velocity.

• Greater relief results in more dynamic glacial movement, shaping U-shaped valleys and facilitating erosion.

• In gentler terrain, glaciers move more slowly, leading to thicker ice storage rather than extensive erosion.

Place-Specific Example – The Lake District, UK

• The Great Langdale Valley was carved by a glacier flowing through a steep gradient, producing a dramatic U-shaped valley.

• The Helvellyn range has steep slopes, allowing for rapid ice movement and the formation of arêtes and hanging valleys.

• The gentler slopes near Keswick result in slower-moving glaciers, depositing more glacial sediments.

formation of glacier ice

• Initial Snowfall: Snow falls and remains frozen throughout the year due to persistently low temperatures.

• Layering Over Time: The following year's snowfall adds layers, compressing previous snow deposits.

• Compaction Begins (Névé Stage): Fresh snow is low-density and flaky, but over time, increased pressure expels trapped air, making it more compact—this early stage snow is called névé.

• Transformation to Firn: If the snow survives one summer without melting, it compacts further and becomes firn, a denser intermediate stage between snow and ice.

• Glacial Ice Formation (Diagenesis): Continued compression over years or centuries leads to the formation of true glacial ice, which is more solid and bluish in color due to the lack of air bubbles.

• Minimum Depth for True Glacial Ice: Once ice accumulates to a thickness of at least 100 meters, it is classified as true glacial ice, capable of flowing and reshaping landscapes.

valley glaciers and ice sheets

Valley Glacier	Most glaciers in the Alps	Larger masses of ice which move down from either an icefield or a cirque basin source.  They usually follow previously formed river courses and are bounded by steep sides and have steep ice free sides overlooking the glacier surface which are important sources of debris, and snow. Typically 10-30km long, but can be longer. Usually they are confined by valley sides. They follow the course of existing river valleys.
Icecaps and ice sheets	Antarctica (13.6million Km2 and volume of about 30million Km3) and Greenland	Huge areas of ice which spread outwards from central domes.  Except nunataks (exposed summits) the whole landscape is buried.  Ice sheets once covered much of Northern Europe and North America. They extend for more than 50,000km2  .  Today they contain 96% of the world’s ice. There are currently only two ice sheets – Antarctica and Greenland.

warm-based glaciers characteristics

warm-based glaciers how do they move

cold-based glaciers characteristics

cold-based glaciers how do they move

basal sliding

internal deformation

open systems

Energy and matter can be transferred from neighbouring systems as an input and can also be transferred to neighbouring systems as an output.

pressure melting point

Glacier movement = influenced by temperature

• The character and movement of ice depends on whether it is warm or cold, which depends on the pressure melting point (PMP).

• The PMP is the temperature at which ice is on the verge of melting

• A small increase in pressure can therefore cause melting

• PMP is normally 0'C on the surface of a glacier, but it can be lower within one/at the bottom/base (due to an increase in pressure caused by either the weight or the movement of ice)

• In other words, as pressure increases, the freezing point for water falls below 0'C

This is because the spreading out action of the water molecules during freezing means that applying pressure to water lowers the freezing point.