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Describe and explain constructive plate boundaries. - Leaving Cert Geography - Question 1C - 2020
Question 1C
Describe and explain constructive plate boundaries.
Worked Solution & Example Answer:Describe and explain constructive plate boundaries. - Leaving Cert Geography - Question 1C - 2020
Step 1
Description of Constructive Plate Boundaries
Answer
Constructive plate boundaries, also known as divergent boundaries, occur where two tectonic plates are moving away from each other. This movement allows magma from the mantle to rise to the surface, creating new oceanic crust.
One of the most well-known examples of constructive boundaries is the Mid-Atlantic Ridge, where the Eurasian Plate and North American Plate are separating. This boundary is characterized by volcanic activity, which leads to the formation of underwater volcanoes and the expansion of ocean floors.
Step 2
Explanation of Processes Involved
Answer
The process of seafloor spreading is fundamental to constructive plate boundaries. As plates move apart, the gap created is filled by magma, which then cools and solidifies to form new crust. This process not only leads to the formation of new land but also contributes to geological features such as rift valleys.
Additionally, this movement can lead to earthquakes as the plates adjust and shift, releasing built-up pressure in the Earth's crust. Although generally less violent than those occurring at destructive margins, these earthquakes can still significantly impact the surrounding areas.
Step 3
Locational Examples
Answer
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The East African Rift Valley
- This is another example of constructive boundaries where the African Plate is splitting into two smaller plates, leading to rifting and volcanic activity.
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The Red Sea Rift
- The divergent boundary between the African Plate and the Arabian Plate is creating new land and widening the Red Sea over geological time.
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The Icelandic divergence
- Iceland is situated on the Mid-Atlantic Ridge and experiences extensive volcanic activity due to the constructive plate boundary beneath it.
Step 4
Illustration of Constructive Boundaries
Answer
A relevant diagram illustrating a constructive plate boundary can enhance understanding. The diagram should depict two tectonic plates moving apart with arrows indicating their motion, a rising magma plume, and the newly formed oceanic crust. This illustration aids in visualizing the processes of seafloor spreading and volcanic activity associated with constructive boundaries.