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Explain, with reference to examples you have studied, how plate tectonics helps us understand the forces at work along crustal plate boundaries. - Leaving Cert Geography - Question B - 2009
Question B
Explain, with reference to examples you have studied, how plate tectonics helps us understand the forces at work along crustal plate boundaries.
Worked Solution & Example Answer:Explain, with reference to examples you have studied, how plate tectonics helps us understand the forces at work along crustal plate boundaries. - Leaving Cert Geography - Question B - 2009
Step 1
Name two forces:
Answer
The two primary forces involved in plate tectonics are:
- Slab Pull - This force occurs when a denser oceanic plate sinks beneath a less dense continental plate at a subduction zone, pulling the rest of the plate along with it.
- Ridge Push - This force arises at mid-ocean ridges where magma rises to create new crust, pushing older crust away from the ridge due to gravitational forces.
Step 2
Name examples of different boundaries:
Answer
Examples of different types of plate boundaries are:
- Convergent Boundaries - such as the boundary between the Pacific Plate and the North American Plate, where subduction occurs, leading to the formation of chains of volcanoes.
- Divergent Boundaries - for instance, the Mid-Atlantic Ridge, where two oceanic plates are moving apart, allowing magma to rise and create new oceanic crust.
Step 3
Discussion:
Answer
Plate tectonics provides insight into the dynamic processes at work along crustal plate boundaries. The interaction of the different plates can lead to various geological features and phenomena, which include:
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Earthquakes - These occur primarily at plate boundaries due to the movement and friction between tectonic plates. The release of stress accumulated along fault lines can cause seismic waves, leading to tremors felt at the surface.
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Volcanoes - When an oceanic plate subducts under a continental plate, the descending slab causes melting in the mantle, leading to volcanic activity. For example, the Cascadia Subduction Zone off the coast of Washington is a prime location for volcanic eruptions due to the interaction of these plates.
In summary, the forces at work—such as slab pull and ridge push—play critical roles in shaping the Earth's surface. The resulting consequences of these tectonic movements not only contribute to the formation of mountains and ocean basins but also pose significant natural hazards to human populations.
Diagrams
To further illustrate these concepts, it's beneficial to include diagrams depicting:
- The process of subduction, showing the movement of the plates and the creation of volcanic arcs.
- The formation of new crust at divergent boundaries, highlighting how magma emerges at mid-ocean ridges.
Providing analyzed and annotated diagrams can enhance understanding and illustrate the forces operating at plate margins.