GL12 Analysing Geomorphic Processes Flashcards
How and why does the size and type of rock affect the rate of erosion?
- The size and type of rock scraping the bedrock affects the rate and intensity of erosion. Harder rocks are less easily eroded, while softer rocks are more easily eroded, particularly by abrasion.
- When a glacier moves over a surface, the debris embedded in its base/sides, scours the surface rocks, wearing them away.
- The source material will scrape and scratch the rock.
- Finer material will smooth and polish the rock. The larger the size of the rocks scraping against the bedrock, the more intense the erosion.
How and why does the force of the glacier affect the rate and intensity of deposition?
- The force of the glacier affects the rate and intensity of deposition. Deposition occurs when the kinetic energy of the glacier is not sufficient to entrain large particles, usually in the accumulation zone.
- The kinetic movement energy of the glacier must be enough to entrain large particles. If the force of the glacier is weak, deposition will occur instead of erosion.
- Factors that affect the force of the glacier include the temperature, the slope of the glacier, and the weight of the glacier.The force of the glacier affects the rate and intensity of deposition.
How and why does the softness of the rock affect the rate of physical weathering?
- The softness of the rock affects the rate of mechanical weathering. Physical weathering factors like freeze-thaw and frost shattering cause water to enter cracks in the rock, which then freezes and expands.
- This expansion exerts pressure on the rock, causing it to crack or split off. The more frequent the fluctuations of temperature above and below the freezing point, the more effective the process is.
- Soft rocks are more likely to break and crumble due to mechanical weathering, while harder rocks resist these processes.
How and why do warmer temperatures increase the rate of chemical weathering?
- Warmer temperatures increase the rate of chemical weathering. Chemical weathering occurs when rock minerals react with substances like oxygen, carbon dioxide, or water to produce new compounds.
- Warmer temperatures speed up the reaction rates, allowing for more rapid weathering.
- For example, carbonation occurs when rainwater combines with dissolved CO2 from the atmosphere to produce a weak carbonic acid that dissolves the rock over time.
- The solubility of some minerals increases under acidic conditions, and this can result in the original rock structure being destroyed.
What is the kinetic energy of the glacier?
The kinetic movement energy of the glacier is the energy required to entrain large particles for transport. The velocity, which is affected by temperature, affects the rate and intensity of transport.
What is the input and output of energy and material involved in abrasion?
- Debris taken from the bed or sides of the glacial valley (usually by plucking) is input into the system.
- This material is transported through the system as a throughput, ground against the rock wearing it away like sandpaper in the process of abrasion.
- The energy for the process comes from the kinetic movement energy of the glacier
What is the input and output of energy and material involved in plucking?
- For plucking, there are transfers of both energy and material. The inputs of material in the accumulation zone through precipitation provide weight of the glacier increasing Gravitational potential energy.
- Changes in thermal energy throughout the glacier cause some areas to pass the pressure melting point and melt. The water fills cracks in the rock and then freezes as the temperature drops again.
- Continued kinetic energy moving the glacier then drags the debris from the sides or bed of the glacier entraining it within to use as a tool of abrasion.
What are the different types of transport in a glaciated landscape?
The different types of transport in a glaciated landscape are englacial, supraglacial, and subglacial.
What are the factors that prepare the landscape for direct glacial erosion?
- There are four ways that the landscape is prepared for direct glacial erosion: (1) the removal of surface material by natural processes, (2) erosion by processes acting in cold, nonglacial environments, (3) erosion by processes acting in environments influenced by glaciers, and (4) erosion by the weight of overlying ice during major glacial periods.
What are the different spatial variations of geomorphic processes?
Geomorphic processes can occur above the glacier, within/surface/base of the glacier, at the snout, and beyond the glacier.
What is the temporal variation in geomorphic processes?
The rate and intensity of geomorphic processes can vary over time due to changes in climate, temperature, and other environmental factors. This variation can be seen in the different stages of glacial advance and retreat, as well as in the different types of weathering and mass movements that occur in a glaciated landscape.
