Marine Geology – Continental Margins Which part of the continental margin is structurally a submerged extension of the continent itself (with continental crust, gentle gradients, and shallow depths)?

Introduction / Context:
Continental margins include the shelf, slope, and rise, transitioning from continental crust to the deep ocean basin. Recognizing which portion is geologically part of the continent is central to marine geology, resource exploration, and maritime boundary law (e.g., Exclusive Economic Zones).

Given Data / Assumptions:

• We are concerned with structural affiliation (continental crust) rather than merely bathymetric position.
• Typical features: low relief, shallow water (often to ~200 m), gentle gradients.
• Terminology follows standard oceanography.

Concept / Approach:
The continental shelf is the flooded, gently sloping extension of the continent composed of continental crust. The continental slope marks a steeper descent to the abyssal plain and generally transitions toward oceanic crust; it is not considered part of the continental block in the same structural sense.

Step-by-Step Solution:

Verification / Alternative check:
Standard profiles show wide shelves on passive margins (e.g., Atlantic) consisting of continental crust, while the slope is where thickness and composition transition to oceanic characteristics.

Why Other Options Are Wrong:

• Continental Slope: Steep boundary; not the shallow, gently sloping continental extension.
• Both (a) and (b): Incorrect because the slope does not meet the structural criterion.
• None of the above: False, as the shelf clearly fits.

Common Pitfalls:
Assuming “margin” implies the entire edge is the same crustal type. The shelf is continental; the slope is a transitional feature toward oceanic domains.

Final Answer:
Continental shelf