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North America

North America - Geology

The oldest stable core (craton) of the North American continent is made up of a large Precambrian-Cambrian continent, Laurentia, where the bedrock is today exposed in the Canadian Shield and Greenland, while in the interior (Interior Platform) is covered by younger deposits and basins. The core area is in the north, east and south surrounded by Paleozoic folding belts, which are shot over the craton of the Ellesmeric Folding Belt in northern Canada and Greenland, the Northern Caledonian folding belt, the Appalachians and the Ouachita Mountains. The North American mountain ranges west of the craton developed from Mesozoic and Tertiary, as seabed dispersal in the then Pacific brought several oceanic plates obliquely toward subduction zones off the west coast of North America. Towed crustal fragments from archipelago and volcanic plateaus and scrapped seabed formation were displaced along the coast and united with the continent. From the subduction zones penetrated intermediate to acidic magmas and solidified in large intrusions (batholiths), i. in Sierra Nevada, and gave rise to violent eruptions. Several volcanoes remain active (for example, in the Cascade Range and the Alaska Aleutians). In Tertiary, lateral displacement and compression of the coastal chains continued; in the Basin Range Province (Great Basin) stretching of the earth's crust (extension) occurred, with the erosion of large crustal areas and widespread block rejection. In the Columbia-Snake-River area and in Mexico, the fold mountains are overlain by thick basaltic lava flows. The Colorado Plateau (Grand Canyon) is an isolated remnant from the craton. In the eastern Rocky Mountains, recess and foreland deposits have been shot across the Interior Platform. According to, NA stands for North America.

Now the Pacific plate itself is brought down into the subduction zone below Alaska and the Aleuter Arch, and south of 50 N. the scattering zone is close to or below the continent and is divided by large transformative faults. The zone is offset sideways along the San Andreas fault, which has passed it to the Gulf of California. Here it has "spotted" the California Peninsula of the North American Plate. Mexico's and Central America's Cordillera branches into the Andes Mountains of South America and the Caribbean, where a subduction zone leads the ocean floor from the Atlantic Ocean below the Caribbean.

Where the North American continent borders the North Arctic, Atlantic, Davis Strait and Gulf of Mexico, passive margins have been developed since the Mesozoic, where thick deposits of land material (clastic sediments) and carbonates have been deposited. During the Gulf of Mexico and the coastal plain north of it, evaporites from the Jurassic (c. 206-142 million years) form a large salt- shore province.

Mineral raw materials

North America is rich in mineral resources. The central shield has ribboned iron ore at Lake Superior and some of the world's largest gold deposits with gold deposits, Homestake, at Kirkland Lake, as well as massive sulphide deposits (Kidd Creek). Also on the shield is the world's largest nickel deposit, Sudbury. The Palaeozoic folding belts have in the North Elesmeric lead and zinc deposits, Polaris, and in the east are Appalachian massive sulfide deposits, Ducktown. Large sedimentary deposits are widespread; examples are uranium in sandstone in the Colorado Plateau and Key Lake, copper, lead and zinc in clastic sediments (Sullivan, Red Dog) and lead-zinc in carbonate rocks, the so-called Mississippi Valley type, in Tennessee. The Mesozoic and Tertiary folding chain along the west coast of North America has a wealth of mineral deposits, among others. copper deposits with copper (Bingham Canyon, Bisbee) and with molybdenum (Climax) and gold deposits in Nevada. Tungsands gold deposits are known from gold fever days in California, Alaska and Yukon. North America is also a major producer of industrial minerals such as borax from Death Valley.

Central American vegetation

The vegetation is largely determined by the climate. The Central America is a continent divided into two parts, the island and the mainland, and features in most of its territory tropical climates due to its location close to the equator. The exception is the mountain range that cuts its continental part in the south-north direction, which presents cold climates due to the altitude.

The tropical climates are found in the island portion and the coastal east and west of the mainland. The tropical savanna is found in the western portion of the great islands: Cuba, Jamaica, in addition to the Dominican Republic and Haiti, which share the island of Hispaniola. This vegetation is characterized by large fields with the presence of some bushes and flat-topped trees. The tropical savanna climate has a two-season regime, one dry and the other humid, forcing the vegetation to adapt to the dry regime. These adaptations include small, thick leaves and rough skin, or leaves covered with wax or hair, reducing plant transpiration and keeping the moisture collected during the rainy season. Small islands, to the west of the large islands and the mainland, are dominated by tropical and equatorial forests. The rainforest climate is extremely humid and hot throughout the year, which ended up causing a great differentiation of species in tropical forests, which have the greatest biodiversity the globe. This diversity is presented in a canopy of hearts divided into three niches: the upper, between 50 and 60 meters, medium (the densest), between 20 and 40 meters, and the lower, between 5 and 15 meters. There is little or no vegetation cover below five meters, as the canopy is so dense that only 1% of sunlight can reach the ground. On the western coast of the mainland, we have the seasonal tropical forest, with a discontinuous canopy and medium-sized trees, up to 20 meters, and deciduous, which lose their leaves in the dry season. The discontinuous canopy and the loss of leaves in the dry season allow the insolation of the soil and, thus, the appearance of undergrowth.

Non-tropical vegetation dominates the highest parts of the mountain range in the center of the continental portion and in the northwest of the same. In the highest parts we find the forest of altitude. Unlike the northern coniferous forest, the Central American forest has more varied species, with a discontinuous and well-stratified canopy, no more than 30 meters high. The height and density of the canopy varies according to the elevation in which the forest is located, going from a dense forest to a formation of fields of altitude, with a formation of grasses and low shrubs. The desert vegetation is found in the northwest of the continental part, characterized by cacti and xerophyte shrubs, adapted to the dry climate. Adaptations include long and capillarized main root, for better absorption of moisture in the soil, succulent stem to retain liquids, wax coating and hair, to prevent water loss.

Countries in North America
  1. Antigua and Barbuda
  2. Bahamas
  3. Barbados
  4. Belize
  5. Canada
  6. Costa Rica
  7. Cuba
  8. Dominica
  9. Dominican Republic
  10. El Salvador
  11. Greenland
  12. Grenada
  13. Guatemala
  14. Haiti
  15. Honduras
  16. Jamaica
  17. Mexico
  18. Nicaragua
  19. Panama
  20. Saint Kitts and Nevis
  21. Saint Lucia
  22. Saint Vincent and the Grenadines
  23. Trinidad and Tobago
  24. United States

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