The continental margin near an area of lithospheric plate divergence; also called an Atlantic-type margin.

The continental margin near an area of lithospheric plate divergence; also called an Atlantic-type margin.

• A. Passive Margin
• B. Island Arc
• C. Ocean Basin
• D. Hydrothermal Vent

Answer: (A)

When a continent rifts apart at a divergent boundary, the edge of the continent that sits next to the new ocean is a passive margin. This Atlantic-type margin forms because the active plate boundary is at the mid-ocean ridge, away from the continental edge, so there’s little tectonic activity right at the margin itself. Passive margins have broad continental shelves, gentle slopes, and thick sediment buildup from rivers, with far less volcanism or earthquakes than active margins. That combination—divergence creating a new ocean basin, slow boundary activity at the edge, and classic shelf-slope-sediment characteristics—matches the described margin. Island arcs happen at subduction zones with strong tectonics, hydrothermal vents are features at spreading centers rather than margin types, and an ocean basin is the deep-water area, not the continental margin itself.

When a continent rifts apart at a divergent boundary, the edge of the continent that sits next to the new ocean is a passive margin. This Atlantic-type margin forms because the active plate boundary is at the mid-ocean ridge, away from the continental edge, so there’s little tectonic activity right at the margin itself. Passive margins have broad continental shelves, gentle slopes, and thick sediment buildup from rivers, with far less volcanism or earthquakes than active margins. That combination—divergence creating a new ocean basin, slow boundary activity at the edge, and classic shelf-slope-sediment characteristics—matches the described margin. Island arcs happen at subduction zones with strong tectonics, hydrothermal vents are features at spreading centers rather than margin types, and an ocean basin is the deep-water area, not the continental margin itself.