Continental Margin


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Related to Continental Margin: Continental Rise, continental slope, Ocean basin

continental margin

[¦känt·ən¦ent·əl ′mär·jən]
(geology)
Those provinces between the shoreline and the deep-sea bottom; generally consists of the continental borderland, shelf, slope, and rise.

Continental Margin

 

the peripheral area of the floor of the world’s ocean constituting, in geological structure and relief, a continuation of the continental land.

The total area of the continental margin is about 81.5 million sq km. It consists of the shelf, the continental slope, and the continental rise. The earth’s crust in the continental margin is of the continental type. In certain regions the continental margin is characterized by somewhat rugged relief and by the absence of a clear division into the shelf, slope, and rise. In tectonic terms, the continental margin is usually classified among the continental platforms, but, in some places, seismic and volcanic activity are observed. The continental margin is the arena of the most active submarine processes (wave action, tides, currents, floating ice and organisms).

Owing to the proximity of dry land, a great deal of terrigenous material is deposited in the continental margin. The thickest deposits form in the depressions of the shelf, on the marginal plateaus, and in the continental rise. The continental margin is noted for the great variety of benthic deposits, particularly within the shelf. This is explained not only by the diversity of facies distribution but also by the broad distribution of relic deposits of subaerial genesis on the shelf. The continental margin is the most accessible part of the ocean floor for development. Oil and gas deposits on the shelf are currently being exploited.

O. K. LEONT’EV

References in periodicals archive ?
Russia has been attempting to chart the Arctic Ocean's enormous underwater Lomonosov Ridge in an attempt to show that it is an extension of Russia's continental margin.
Using elemental abundances to tectonic setting criteria by Bhatia and Crook (1986), an active continental margin is the most likely setting for most of the Northland Allochthon samples because of high abundance of aluminosilicates.
As mentioned previously, a wider-than-average continental margin warrants the expansion of the continental shelf, as defined in the Law of the Sea Convention, up to more than 350 nautical miles from the baseline.
Detrital zircon studies reported by Dickinson and Gehrels (2003) confirm a suggestion made first by Dickinson (1988) that much of the thick Paleozoic and early Mesozoic detrital succession present in the Colorado Plateau area (including the units exposed in the Grand Canyon) were derived by uplift and erosion of the eastern continental margin.
Geomorphology and stability of the continental margin constitute a priority scientific objective of CANA and Bathymetric data are also essential to understand and manage fishery resources.
An "oceanic ridge" is not part of the continental margin at all, (73) suggesting that a coastal state cannot rely on an oceanic ridge to extend its continental shelf beyond 200 miles from baselines.
In the Holocene Transgression (T), the southeast continental margin has not received any significant quantity of terrigenous supply.
Gas hydrates have been well-studied in the Makran region of the Pakistan continental margin, although few indications have so far been noted of their widespread presence in the Indus Fan region.
Thus, every coastal state has a right to the continental shelf out to the 200 nm limit as part of the EEZ, regardless of whether the continental margin actually extends that distance offshore.

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