Using the plate tectonic theory explain the differences between the continental shelves on the east and west coasts of South America.
To understand the differences between the continental shelves on the east and west coasts of South America, we can utilize the plate tectonic theory. This theory helps explain the movement and interaction of Earth's lithospheric plates. Here's a step-by-step breakdown of how to make this connection:
1. Understand the Plate Tectonic Theory:
The plate tectonic theory states that the Earth's lithosphere, which is divided into several large and small plates, moves due to the convection currents in the underlying asthenosphere.
2. Identify the South American Plate:
To explain the differences in continental shelves, it's important to know the plate on which South America is located. South America primarily sits on the South American Plate, which is a major tectonic plate.
3. Explore Subduction Zones:
On the west coast of South America, we find a convergent plate boundary, specifically a subduction zone. The Nazca Plate is an oceanic plate that is being subducted beneath the South American Plate. This subduction process creates the Andes Mountains, which run parallel to South America's west coast. Due to this subduction, the continental shelf on the west coast of South America is narrow, limited in width.
4. Understand Divergent Boundaries:
On the east coast of South America, we find a divergent plate boundary, specifically the Mid-Atlantic Ridge. The South American Plate and the African Plate are moving apart, causing the creation of new oceanic crust in the Atlantic Ocean. This divergence results in the separation of the South American Plate from the African Plate and the formation of a broad continental shelf along the east coast of South America.
5. Consider Sedimentation:
Another contributing factor for the differences in continental shelves can be sedimentation. Over time, rivers from the continent deposit sediment near the coastlines, which can influence shelf width. However, the primary factor in the case of South America is related to plate tectonics.
In summary, the differences between the continental shelves on the east and west coasts of South America can be explained by the plate tectonic theory. The west coast experiences subduction, resulting in a narrow continental shelf due to the convergence of the Nazca Plate with the South American Plate. On the east coast, the divergent boundary between the South American and African Plates leads to a broader continental shelf.