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Surface Processes Answer (i) or (ii) - Leaving Cert Geography - Question B - 2012
Question B
Surface Processes Answer (i) or (ii). (i) Explain, with the aid of diagrams, the formation of any two different Irish landforms that you have studied. OR (ii) De... show full transcript
Worked Solution & Example Answer:Surface Processes Answer (i) or (ii) - Leaving Cert Geography - Question B - 2012
Step 1
Explain, with the aid of diagrams, the formation of any two different Irish landforms that you have studied.
Answer
To answer this question, we will explain the formation of two distinct Irish landforms: the limestone pavement and the drumlin, supported by diagrams.
Limestone Pavement Formation
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Definition and Location: Limestone pavement is characterized by its flat, exposed rock surface, commonly found in areas like the Burren in County Clare.
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Formation Process: The primary process involved in the formation of limestone pavement is chemical weathering due to carbonation. Rainwater absorbs carbon dioxide from the atmosphere and soil, forming a weak carbonic acid. This acid reacts with limestone (calcium carbonate), illustrating the process:
ightarrow ext{Ca}^{2+} + 2 ext{HCO}_3^{-}$$
- Diagrams: A diagram would show the surface of limestone with typical features such as karren (grooves formed by weathering) and clints (blocks of limestone).
Drumlins Formation
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Definition and Location: Drumlins are streamlined hills of glacial till, found mainly in the midlands of Ireland.
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Formation Process: Drumlins are formed by the action of glaciers. As glaciers advance, they deposit material in a teardrop shape. The streamlined shape occurs because the glacier molds the till below it as it moves:
ightarrow ext{Till Deposition} ightarrow ext{Drumlin Shape}$$
- Diagrams: A diagram would depict the cross-section of a drumlin showing the layers of sediment, highlighting the direction of glacier movement.
Step 2
Describe and explain any two processes of mass movement.
Answer
In response to this part of the question, we will describe and explain two processes of mass movement: slumping and mudflow.
Slumping
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Definition: Slumping is a type of rotational slide that occurs on steep slopes. It often involves the movement of a mass of earth material down a curved surface.
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Process Explained: Slumping typically occurs after heavy rainfall when the increased weight of water saturates the soil, reducing friction. This leads to a rotational movement of the soil, as seen in:
- Preparation: Water saturation increases pore water pressure.
- Movement: The saturated material rotates downwards.
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Example: In Ireland, areas like the coast of Antrim show examples of slumping. Diagrams can illustrate the affected area before and after slumping, highlighting the curved movement.
Mudflow
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Definition: Mudflow is a fast-moving flow of soil and rock mixed with water, occurring on slopes with a gradient.
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Process Explained: This process can be triggered by heavy rainfall or rapid snowmelt, leading to liquefaction of the soil. Key points include:
- Triggering Conditions: Heavy rainfall saturates the soil, causing rapid flow.
- Movement: Once the soil reaches a critical angle, it begins to flow downhill.
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Example: The mudflows in Western Ireland provide clear evidence of this phenomenon. A diagram would show the flow path and the area impacted by the mudflow.