What is the difference between an active continental margin and a passive continental margin?
a.
A passive margin is the site of an ancient continental rift, left behind when seafloor spreading moved offshore, whereas an active margin is an active plate boundary.
b.
A passive margin is passively carried along by plate tectonics in a transform system, like the San Andreas whereas an active margin is a trench.
c.
An active margin receives large amounts of sediment whereas a passive margin is sediment starved
d.
An active margin has earthquakes whereas a passive margin has quiet erupting (aka passive) volcanoes
The Correct Answer and Explanation is :
The correct answer is:
a. A passive margin is the site of an ancient continental rift, left behind when seafloor spreading moved offshore, whereas an active margin is an active plate boundary.
Explanation:
The Earth’s lithosphere is divided into tectonic plates that move and interact with each other along different types of plate boundaries. These interactions lead to the formation of two types of continental margins: active and passive.
- Active Continental Margin:
- An active margin is typically found at plate boundaries, where tectonic plates interact. These margins are often associated with significant geological activity such as earthquakes, volcanic eruptions, and mountain-building processes. Active margins are usually located along subduction zones, transform faults, or convergent plate boundaries, where one plate is either sliding past, colliding with, or being forced beneath another.
- A characteristic feature of active margins is the presence of deep ocean trenches, volcanic arcs, and seismic activity due to the ongoing tectonic interactions.
- For example, the western edge of the Americas (like the Pacific coast of South America) is an active continental margin because it is located near subduction zones where oceanic plates are being forced under continental plates.
- Passive Continental Margin:
- A passive margin, on the other hand, is not associated with any active plate boundaries. These margins are typically formed in regions where tectonic plates are not actively interacting. They are often the result of continental rifting during the early stages of seafloor spreading when the continental plate splits and begins to drift away from the mid-ocean ridges.
- These margins are characterized by wide continental shelves, shallow waters, and the absence of volcanic activity or earthquakes.
- For example, the eastern coasts of the Americas (like the U.S. East Coast) represent passive margins, as these areas are not close to any tectonic boundaries.
Key Differences:
- Active Margin: Tectonic plate boundary, associated with earthquakes, volcanic activity, and ocean trenches.
- Passive Margin: Not at a plate boundary, characterized by minimal tectonic activity, wide continental shelves, and gentle sloping seabed.
Image Generation Request:
Now, I will generate an image to visually illustrate the difference between an active and passive continental margin.
Here is the image illustrating the difference between an active continental margin and a passive continental margin. The left side represents the active margin with tectonic plate boundaries, subduction zones, and volcanic arcs, while the right side shows the passive margin with a wide continental shelf and minimal geological activity.
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