For purposes of study, the continental margin is usually subdivided into three major sections: the continental shelf, the continental slope, and the continental rise. In addition to these sections, one of the most important features of the continental margin is the presence of very large submarine canyons that cut their way through the continental slope and, less commonly, the continental shelf .
What is the continental margin made of?
The continental margin is that part of the ocean floor at the edges of the continents and major islands where, just beyond the shoreline, it tapers gently into the deep sea. The continental margin is made up of the continental shelf, the continental slope, and the continental rise.
What are the continental margins on the trailing side of tectonic plates?
The continental margins on the trailing side of the tectonic plates are those which are around the Atlantic Ocean; they are broad, featured with gentle continental slopes and with continental rise very well-developed.
How much of the ocean is consumed by the continental margins?
The Continental margins consume about 28% of the area of the ocean. Continental margins are on the leading edges of the tectonic plates, these are similar to the rim of the Pacific Ocean which are usually narrow and have steep continental slopes. In this case, either the poorly developed continental rises or none of the continents rises at all.
Why is the continental margin important to humans?
The continental margin is the ocean area most easily reached by humans and so it has an important effect on human life. About 90 percent of the world’s marine food resources come from the waters over the continental shelves. Most of those resources consist of fish.
What is the continental margin made up of?
Continental margins are made of thick accumulations of sedimentary rock, the type of rock in which oil and gas generally occur.
What are three major features of a passive continental margin?
The features comprising passive continental margins include the continental shelf (the flooded extension of the continent), the continental slope (has the steepest slope), and the continental rise.
What are main features of continental margins?
Major Continental Margin FeaturesContinental shelf. This is very shallow water, and underlain by continental crust. ... Continental slope. This is much steeper than the shelf, usually about 3° but ranging from 1-10°. ... Continental rise. ... Abyssal plains.
What are the types of continental margins?
Continental margins typically fall into two classes: "active" and "passive." The West Coast of the United States is an active margin that is characterized by rugged coastlines with narrow beaches and steep sea cliffs.
What are three major features of a passive continental margin quizlet?
A passive continental margin is tectonically inactive and features a continental shelf, a continental slope, and a continental rise (from land toward the sea); An active continental margin is located along a convergent plate boundary, has a deep-ocean trench where subduction takes place, and may have evidence of an ...
What is the continental margin quizlet?
Continental margin. the zone of the ocean floor that separates the thin oceanic crust from thick continental crust.
What is not part of the continental margin?
Which of the following is NOT part of the continental margin? coral reefs surrounding a lagoon. You just studied 65 terms!
How is active continental margin formed?
An active continental margin is found on the leading edge of the continent where it is crashing into an oceanic plate. An excellent example is the west coast of South America. Active margins are commonly the sites of tectonic activity: earthquakes, volcanoes, mountain building, and the formation of new igneous rock.
Which one of the following is part of the passive continental margin?
The Atlantic and Gulf coasts show the classic form of a passive continental margin: a low-lying coastal plain, broad continental shelf, then a steep continental slope, gentle continental rise, and flat abyssal plain. This topography is a consequence of the transition from thick continental to thin oceanic crust.
What are sediments found on continental margins called?
Sediments found on continental margins are called: neritic.
Why are continental margins important?
The continental margins are of great importance for many reasons, not least of which is that they are presently the source of increasing amounts of crude oil and natural gas supplies.
What is the role of the shelf region in the continental margin?
In the case of continental margin, the shelf region acts as the main staging area for the sediments to disperse into the deepwater areas. Due to tectonic movements and continuous changes in sea level at the coast, topographic changes takes place in the shelf as well as slope areas.
What are the features of the Arabian Sea?
The WCMI and the adjoining deep oceanic areas of the eastern Arabian Sea consist of numerous structural features namely, the Laccadive ridge, the Laxmi ridge, the Prathap ridge complex, and the Panikkar ridge, which are mostly buried under the sediments ( Naini and Talwani, 1982 ). The Laccadive and Laxmi ridges divide the eastern Arabian Sea into the Western and Eastern basins ( Fig. 3.4 ). While the geophysical studies indicate that the Western basin is underlain by oceanic crust ( Chaubey et al., 1995; McKenzie and Scalter, 1971; Naini and Talwani, 1982; Whitmarsh, 1974 ), the nature of crust below the Eastern basin could not be clearly established.
How many miles of coastline does the SLA cover?
States were given jurisdiction over any natural resources within 3 nautical miles (3.45 miles) of the coastline excepting Texas and the west coast of Florida where the SLA extends the States’ Gulf of Mexico jurisdiction to 9 nautical miles (10.35 miles).
What is the tectonic framework of the present day continental margin of India?
The tectonic framework of the present-day continental margin of India and the wide variations in morphology, structure, sedimentation, volcanic activity, and so on observed along its various segments basically reflect that these segments have evolved through a variety of tectonomagmatic processes and varied breakup history (passive/active rifting, shearing) during their evolution. We highlighted in this chapter some of the above issues as they have direct relevance to proper evaluation of petroleum system along the Indian continental margins. A table summarizing the structural setup and petroleum system of the offshore basins is provided along with a description of reservoir potential of the deepwater depositional system in the Bengal Fan.
What are the characteristics of volcanic rock in the Cordilleran continental margin volcanic arc?
The characteristics of volcanic rock in the Cordilleran continental margin volcanic arc are similar to those in the west Pacific intraoceanic arc; that is, dominated by intermediate andesite, the volcanic rock has apparent horizontal zonality in the direction from trench to land.
What is the Cordilleran volcanic arc?
The Cordilleran continental margin volcanic arc mainly refers to the Cordilleran mountain range zone in South America, and it, together with the west Pacific volcanic arc zone, composes the circum-Pacific volcanic circle, which has a total length of more than 40,000 km. There are 30 active volcanoes in the south section of the Andes, the Cordillera mountain system, and 16 active volcanoes in the north section. The Llullaillaco volcano in the middle with an altitude of 6723 m is the highest active volcano in the world. The characteristics of volcanic rock in the Cordilleran continental margin volcanic arc are similar to those in the west Pacific intraoceanic arc; that is, dominated by intermediate andesite, the volcanic rock has apparent horizontal zonality in the direction from trench to land. The main eruption mode is centered eruption.
What is the continental margin?
The continental margin is that part of the ocean floor at the edges of the continents and major islands where, just beyond the shoreline, it tapers gently into the deep sea. The continental margin is made up of the continental shelf, the continental slope, and the continental rise.
How is the continental margin determined?
The general shape of the continental margin is usually determined by the shape of the coastline from which it extends. If it extends from a plain, then the margin will be broad and level. If it extends from a mountainous coast, then it will be steep and rocky. Steep cliffs that may have been formed by wave action when the level of the sea was lower may now be submerged and form part of the margin.
How did the continental margin of the United States form?
The continental margin off the northwestern coast of the United States was partly formed by a dam of rock thrust up by earthquake action about 25 million years ago. Where the dam breaks the surface of the water, it forms the Farallon Islands off San Francisco. The shelf is so narrow here—only about 1 mile (1.6 kilometers) wide—that the heads of many submarine canyons reach almost to the shoreline. Large quantities of sand from the beaches are carried by currents down the canyon walls.
What causes tides in the ocean?
Tides are rhythmic movements of the oceans that cause a change in the surface level of the water. They are created by a combination of the gravitational pull of the sun and moon and Earth’s rotation.
How much of the Earth's surface is covered by oceans?
The World Ocean, which is all the oceans taken together, covers a total of 139,782,000 square miles (363,433,200 square kilometers)—about 71 percent of Earth’s surface. Over 200 million years ago, the World Ocean
What are the different parts of the ocean called?
Different parts of the ocean have different features and different kinds of creatures live in them. These different parts are called zones. Some zones are determined by the amount of light that reaches them.
How are reefs formed?
A reef is a ridge or wall of material lying close to the surface of the water just offshore. Reefs are made of rock or coral. A coral reef is a wall formed in shallow ocean areas by small, soft, jellylike animals called corals and marine algae that store calcium deposits. Corals attach themselves to hard surfaces and build a shell-like external skeleton. Many corals live together in colonies. Young coral builds its skeleton next to or on top of older skeletons. Gradually, over hundreds, thousands, or millions of years a wall, or reef, of these skeletons is formed. Reef corals cannot live in cold waters. They are found only in warm waters north and south of the equator. The water must be clear and free of sediment. Coral reefs do not form where rivers flow into the sea.
More About Continental Margins
Continental margins are on the leading edges of the tectonic plates, these are similar to the rim of the Pacific Ocean which are usually narrow and have steep continental slopes. In this case, either the poorly developed continental rises or none of the continents rises at all.
Passive Continental Margin
The passive margin is the transition that occurs between the oceanic area and continental. This is not an active plate margin. The passive margin is formed by the process of sedimentation which is above the ancient rift which is now marked by the transitional lithosphere. The continental rifting is created between the new ocean basins.
Active and Passive Continental Margins
An active continental margin is like a coastal region that is marked by mountain-building activity. This includes the earthquakes, volcanic activity, and tectonic motion thus resulting from the movement of the tectonic plates. The characteristics of the active continental margins include the following:
Continental-Continental Convergent Plate Boundary
There are some lithospheric plates that consist of both the continental and the oceanic crust. The subduction which initiates as an oceanic lithosphere also slides quite beneath the continental crust.
Convergent Collision Plate Boundary
A convergent boundary which is also known as a destructive boundary is generally an area on the Earth’s surface where the two or more of the lithospheric plates collide with each other. One of these plates eventually slides beneath the other, and this process is known as subduction.
Formation of The Continental Margins
The Water Column
Geography of Continental Margins
Plant Life
Animal Life
Human Life
The Food Web
Spotlight on Continental Margins
- Queensland, Australia and The Great Barrier Reef
The Great Barrier Reef, the longest structure in the world created by living organisms, consists of slightly fewer than 3,000 smaller reefs joined together. It covers approximately 132,974 square miles (344,400 square kilometers), which is almost the size of the state of Kansas. At least 500,… - Northwestern Australia and Southeast Asia
On the continental shelf off the coast of northwestern Australia are the islands of Sumatra, Java, Borneo, and the Malaysian Peninsula, the most volcanic islands in the world. Other islands, including New Guinea, New Zealand, and the Philippines, are formed from part of the shelf. Sout…
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