Lesson plan
passive margin
A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting forms new ocean basins. Eventually the continental rift forms a mid-ocean ridge and the locus of extension moves away from the continent-ocean boundary. The transition between the continental and oceanic lithosphere that was originally formed by rifting is known as a passive margin. In summary, passive margins represent broad, non-tectonically active transitions between continental and oceanic lithosphere that evolve from continental rifting to seafloor spreading and subsequent thermal subsidence, producing extensive sedimentary wedges above highly attenuated transitional crust. Recent studies emphasize that passive margin architecture varies laterally over short distances with changes in crustal extension and magmatic flux, leading to magma-poor, magma-rich e intermediate margin segments that influence crustal structure, subsidence history and sediment distribution. These heterogeneities affect basin evolution, resource potential and margin morphology along rifted continental margins.
Article summary
A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting forms new ocean basins. Eventually the continental rift forms a mid-ocean ridge and the locus of extension moves away from the continent-ocean boundary. The transition between the continental and oceanic lithosphere that was originally formed by rifting is known as a passive margin. In summary, passive margins represent broad, non-tectonically active transitions between continental and oceanic lithosphere that evolve from continental rifting to seafloor spreading and subsequent thermal subsidence, producing extensive sedimentary wedges above highly attenuated transitional crust. Recent studies emphasize that passive margin architecture varies laterally over short distances with changes in crustal extension and magmatic flux, leading to magma-poor, magma-rich e intermediate margin segments that influence crustal structure, subsidence history and sediment distribution. These heterogeneities affect basin evolution, resource potential and margin morphology along rifted continental margins.
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Discussion questions
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