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World Continent General Considerations For North America Geological History. During the geological period, the mainland has collided and separated many times. When they separated, it forms a new ocean basin between the divergent fragments through the seafloor propagation procedure.

The propagation, which originates from the ridge of the ocean. It offset (to stay in the surface section of ​​the planet) when sub-ducting. Treatment bent through the seabed and sag along the path towards the tilt inside Earth trenches of the deep sea. The closure of the ocean basin by subduction of the seabed led to a continental collision.

Materials that move from the propagating ridge to a subduction zone include rock blocks as thick as 60 miles (100 km). It calls this hard earth’s outer shell a lithosphere, unlike the hotter, smoother asthenosphere. It calls the part of the lithospheric plate that descends into the asthenosphere in the subduction zone the plate. Many lithospheric plates that make up the current surface of the Earth defined by interconnecting systems of ridges. Subduction zones, and lateral motion cracks (called transition faults). Throughout the geological period, as the new plates formed, expanded, contracted and disappeared, the plate boundary scheme continued to develop.

World Continent General Considerations For North America Geological History

It calls the outermost layer of the lithosphere the cortex. It comprises a low-density material crystallized from molten rock (magma) produced by partial fusion of lithosphere or asthenosphere. The average thickness of the oceanic crust is 4 miles (6.4 km). It localizes the ocean plateau and seamounts areas of the thick oceanic crust generated by underwater volcanic movement. Promoted by thermal jets of magma or pillars rising from the depths of the Earth’s interior (ie, mantle). The oceanic crust is short-lived, formed at the top of the ocean and destroyed in the trenches. Its average age is 60 million years.

The continental crust is thicker, at an average of 22 miles (35 km) and then the oceanic crust. Can explain the average surface elevation of the seabed above 3 miles (4.8 km) (density of the Archimedes principle). The arrangement and origin of the continental crust are more complex than that of the oceanic crust. Formed in the subduction zone. Lateral growth produced by adding scrapers from the upper part of the ocean plate as they sub-duct under the continental margin. This edge marked by a line of volcanoes, often in volcanic arcs, forming an increased to the crust.

The result of partial melting of the asthenosphere wedges on the descending plate. Below the continental plate (by releasing water from slab to promote fusion, which reduces the melting point of the wedge). The subduction zone (a sea plate descending from another ocean plate) in the ocean basin produces volcanic arcs; it calls these island arches. Island arcs make up materials that transition between the ocean and the continental crust, including thickness and composition. The first continent shows to have formed by form several island arcs.

World Continent General Considerations

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Continental crust resists subduction. The average age of the continent near to 2 billion years, over 30 times the average age of the ocean crust. The continent the main repository of information on evolve the Earth’s geology. Knowing their formation requires understanding the processes in their evolving ocean basins.

North America Geological History: Construction framework Structural plane

North America is unusual between continents. Most of the orogenic belts surrounded by an ancient stable low-lying interior. (with associated subduction or continental collisions with old or actual ridges from crustal deformation). These lowlands include the internal platforms of the Laurentian and crystalline rock, covered by a layer of flat sedimentary rock.

The outer orogenic belt of the continent originates from the limits of the plate. They are in the Paleozoic in the east (542-250 million years ago). The Mesozoic in the west (to date, 252.2 million years). The coastal sediments of the Arctic Ocean in the north, the southern Gulf of Mexico. Young volcanic zone in the west cover these areas and damaged. The rupture of the Paleozoic orogenic belt between the Appalachian Mountains in Newfoundland. Caledonian River in eastern Greenland resulted from an unsuccessful seabed expansion along the Mid-Atlantic Ridge and later resolved. To the east, the Appalachians and the Greenland Caledonians separated from Caledonide in Europe.

World Continent General Considerations

North America Geological History: Canadian Shield

Canadian Shield the main section of ​​North America. It exposes the Precambrian rocks (those that exceeded 542 million years of rock) to the surface. The sea between Canada and Greenland destroyed the shield. It expands between the Labrador Sea and the Baffin Bay between 90 million and 40 million years ago. It cracks then moved eastward from Greenland to form the Reykjanes Ridge. Which now separates the North American plate from the European plate. It covers Greenland’s shield with ice. In the past 2.5 million years, the Canadian shield has the center of glaciers. The continental ice sheet has been advancing southward.

Shields are the sum of at least four discrete continents that merged between 2000 and 1.8 billion years ago. The 3 constituent continents act like a solid matrix, recognized the craton, during which it serves as the stable craton; Esclavos’ cratón in the northwest, Nain’s hole is in the northeast, and Craton is in Churchill. The southern part of the province is not a rigid gap and can be a composite origin. It truncates the structural particles of the craton at their edges. It suggests they originated from fragments of the largest continent formed over 2.6 billion years ago. For their age, the small residual basins of the flat Precambrian sedimentary rocks in the shield. Although they are more in common with the internal platforms and basins.

Internal platform and swimming pool

World Continent General Considerations

Horizontal sedimentary rock formations are higher than the Precambrian crust, beyond the boundaries of the Canadian shield. The sedimentation cover is less than a mile thick on the platform. But increases to 2.5 miles it adds 4 km to adjacent channels. 4 miles (6 km) to the outer orogenic belt. Sedimentary rocks give sensitive records of differential settlement in the lower part of the earth. Geomorphological evolution of the outer orogenic belt, sea level fluctuations, and climate changes associated with latitude drift in the continent.

North America Geological History: Paleozoic orogenic belt

They discovered corrosive remains of ancient mountains along the eastern, northern and southern edges of the continent. It formed these .mountains between 400 million and 300 million years ago. When North America collided with other continents to form the ancient Pangea supercontinent. When the Ouachita orogenic belt (mountain) established, they guaranteed it to South America in South America. The Appalachian orogenic belt faces the southeastern margin and northwestern Africa. When the orogenic belt Caledon collided, it faced the northeastern margin of margin and the Franklin orchard. With the balance of the Arctic.

Volcano bracket now collides with the crust north of the Brooks Mountains in Northern Europe and Alaska. The orogenic belt along with the interior of the continent composed of North American native sedimentary rocks. The parts closest to the modern ocean are more diverse, including rock masses that originate outside the continent. A surprising observation of paleogeographic reconstruction is that the current ocean basin. Open along the line near the closed line of the pre-Paleozoic ocean.

Passive continental edge

World Continent General Considerations

Less than 200 million years of sediment and rock cover the eastern, northern and southern margins of the continent. These worn edges extend below the ocean as a shallow continental shelf. Important fishing section formed when the Atlantic and Arctic oceans and the Gulf of Mexico open. The river transports large amounts of sediment to the Gulf of Mexico and the Arctic Ocean. In these two areas, the resulting sediment now drills a salt block like from below a finger. Called a salt dome several miles in diameter. In the Arctic, over 40 million years ago, sediments wrinkled counterclockwise as Greenland moved away from northeastern Canada. Sediments deposited along the Atlantic Ocean’s edge are underwater sediments.

North America Geological History: Mesozoic and Cenozoic orogenic belts

The youngest mountain range (Cordilleras) forms along the western edge of the continent and around the Caribbean Sea. Developed of Cordilleras occurred after the Atlantic opened. North America moved westward to the Pacific region of 180 million years ago. As a result, sedimentary rocks and volcanic rocks fall from the Pacific plate. The Pacific plate subducted and added to the main (western) edge of the continent (so-called suspicious terrain). Volcanic within the continental margin. For 30 million years, North America has been growing beyond the East Pacific.

World Continent General Considerations

The center of submarine expansion, which led to the basic division of Cordilleras. Seafloor west of the diffusion axis moves to one side (north) comparative to North America. Part of continental margin passes through the diffusion peak. (ie, California and northwest) Canada) characterized by faults (San Andreas and Charlotte) Queen (Fairweather) displaced to the right and has no ditches or volcanic arches.

The current bottom of the Caribbean originates from the submarine plateau of the Eastern Pacific Basin. More or less 80 million years ago, it infiltrated the gap between the North and South American plates. As the two plates (including the Western Atlantic) move westward. Subduction and arc volcanic movement take place on the eastern edge of the Caribbean. Where the northern and southern margins of the Caribbean Sea are severed and dismembered. They relate Arctic volcanic action in Central America to the subduction of the Pacific Ocean bottom. The Central American Trench on the Pacific coast of the region; reflected in the Atlantic soil subduction under the volcanic arc of the Lesser Antilles.

Cenozoic volcanic field

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World Continent General Considerations

It relates the volcanic movement of the new generation (ie 65 million years ago) to the subduction zone. The mantle feathers and the procedure of crustal extension. Volcanic arches occur in Lesser Antilles, Central America, the Cascade Mountains, Mexico, the Gulf of Alaska and the Aleutian Islands. Volcanic ash flows covered the vast areas east of major volcanic arcs in Mexico. New Mexico, and from 38 to 28 million years ago. It can scatter the lines (or footprints) of volcanic action from east to west. From melting locations or hot spots below the continental panels. An example of this footprint is the Anahim volcanic belt in central British Columbia. 

The lava plain in the Snake River in Idaho. Yellowstone crater marks the active eastern end of the Snake River track. The basalts of Columbia and the Oregon Plateau, between the ages of 14 to 17 million years. Resemble lava floods associated with set up mantle plumes. Flood basalts on the eastern coast of Greenland and offshore associated with separate Greenland and Northwest Europe. Under the influence of the Icelandic mantle 68 million years ago. It relates the lava in the western coastal areas of Greenland to separate of Greenland and Baffin Island. The Cuenca and Cordillera Mountains are vast bark stretch areas in the western United States. Contain many small volcanic fields, less than 15 million years old.

World Continent General Considerations


Image by Heidi Sadecky from Pixabay

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