Continental margin
Outer edge of continental crust under coastal waters.
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It comprises the continental shelf, continental slope, and continental rise, and is one of three major ocean-floor zones.[1] The boundary between continental crust and oceanic crust beneath coastal waters defines the continental margin.[1] Approximately 28% of the ocean's area is covered by continental margins.[2]
Quick Facts
- Composition
- Continental rise
- continental slope
- continental shelf
- Oceanic area percentage
- 28%
- Shelf width range
- 0.03–1500 km
- Shelf mean slope angle
- 0° 07′
- Types
- Active and passive margins
- Sediment trapped
- 80% of stream load sediment
Facts from the source article.
Key facts and history
The continental shelf is the shallow, flat portion of the margin that transitions from shore toward the ocean.[3] Shelves make up 7% of the sea floor and vary in width from 0.03 to 1500 km worldwide.[3] The shelf ends at the shelf break, where the slope angle increases drastically; the mean shelf angle is 0° 07′.[3] The continental slope often contains V-shaped submarine canyons that cut deeply into shelves and extend to the abyssal plain.[4][1]
At the slope’s base, the sea floor levels out into the continental rise, the outermost margin zone.[1] Continental margins are classified into two categories: active and passive.[1] Lithospheric plate boundaries are where active margins are found, and these areas experience high tectonic activity such as volcanoes and earthquakes.[5]
What the research sources say
The 1979 National Academy of Sciences report "Continental margins" states that continental crust weathers into sands and clays, and 80% of stream sediment is trapped on margins.[6][7] The 2007 textbook "Understanding Earth" describes active margins as typically narrow with steep descents into trenches.[5][8] "Essentials of Oceanography" adds that transform active margins feature many offshore faults creating a continental borderland of islands, banks, and basins.[1][9]
References
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: V., "Essentials of Oceanography", Pearson, 2014-01-01 (we also read that source) en.wikipedia.org
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: Cook, "Continental shelf limits : the scientific and legal interface", Oxford University Press, 2000 (original not read by us) en.wikipedia.org
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: Board., "Continental margins: geological and geophysical research needs and problems", National Academy of Sciences, 1979-01-01; Grotzinger, "Understanding Earth", W H Freeman, 2007, p. 491–496; Gulicher, "Coastal and Submarine Morphology", Butler & Tanner Ltd, 1958, p. 205–215 (we also read that source) en.wikipedia.org
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: Grotzinger, "Understanding Earth", W H Freeman, 2007, p. 491–496; Gulicher, "Coastal and Submarine Morphology", Butler & Tanner Ltd, 1958, p. 205–215 (we also read that source) en.wikipedia.org
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: Grotzinger, "Understanding Earth", W H Freeman, 2007, p. 491–496; Grotzinger, "Understanding Earth", W H Freeman, 2007, p. 491–496 (we also read that source) en.wikipedia.org
- Wikipedia, "Continental margin" (CC BY-SA 4.0), which cites: Board., "Continental margins: geological and geophysical research needs and problems", National Academy of Sciences, 1979-01-01; Board., "Continental margins: geological and geophysical research needs and problems", National Academy of Sciences, 1979-01-01 (we also read that source) en.wikipedia.org
- Open Library record, ISBN 0309027934 ("Continental margins"). CC0 (metadata); book content not read. openlibrary.org
- Open Library record, ISBN 9780716766827 ("Quantitative chemical analysis"). CC0 (metadata); book content not read. openlibrary.org
- Open Library record, ISBN 9780321668127 ("Essentials of oceanography"). CC0 (metadata); book content not read. openlibrary.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Continental margin (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Continental margin (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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