1.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa, Asia and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
2.
Arctic Ocean
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The Arctic Ocean is the smallest and shallowest of the worlds five major oceans. Alternatively, the Arctic Ocean can be seen as the northernmost part of the all-encompassing World Ocean, located mostly in the Arctic north polar region in the middle of the Northern Hemisphere, the Arctic Ocean is almost completely surrounded by Eurasia and North America. It is partly covered by sea ice throughout the year and almost completely in winter, the summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center uses satellite data to provide a record of Arctic sea ice cover. The Arctic may become ice free for the first time in human history within a few years or by 2040, for much of European history, the north polar regions remained largely unexplored and their geography conjectural. He was probably describing loose sea ice known today as growlers or bergy bits, his Thule was probably Norway, early cartographers were unsure whether to draw the region around the North Pole as land or water. The makers of navigational charts, more conservative than some of the more fanciful cartographers, tended to leave the region blank and this lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an Open Polar Sea was persistent, john Barrow, longtime Second Secretary of the British Admiralty, promoted exploration of the region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers Elisha Kane, even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea. Nevertheless, as all the explorers who travelled closer and closer to the reported, the polar ice cap is quite thick. Fridtjof Nansen was the first to make a crossing of the Arctic Ocean. The first surface crossing of the ocean was led by Wally Herbert in 1969, in a dog sled expedition from Alaska to Svalbard, with air support. The first nautical transit of the pole was made in 1958 by the submarine USS Nautilus. Since 1937, Soviet and Russian manned drifting ice stations have extensively monitored the Arctic Ocean, scientific settlements were established on the drift ice and carried thousands of kilometres by ice floes. In World War II, the European region of the Arctic Ocean was heavily contested, the Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2, almost the size of Antarctica. The coastline is 45,390 km long and it is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands. It is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea, countries bordering the Arctic Ocean are, Russia, Norway, Iceland, Greenland, Canada and the United States. There are several ports and harbours around the Arctic Ocean In Alaska, in Canada, ships may anchor at Churchill in Manitoba, Nanisivik in Nunavut, Tuktoyaktuk or Inuvik in the Northwest territories
3.
Canadian Shield
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Composed of igneous rock resulting from its long volcanic history, the area is covered by a thin layer of soil. Human population is sparse, and industrial development is minimal, while mining is prevalent, the Canadian Shield is a physiographic division, consisting of five smaller, physiographic provinces, the Laurentian Upland, Kazan Region, Davis, Hudson and James. The shield extends into the United States as the Adirondack Mountains, the Canadian Shield is U-shaped and is a subsection of the Laurentia craton signifying the area of greatest glacial impact creating the thin soils. The Canadian Shield is more than 3.96 billion years old, the Canadian Shield once had jagged peaks, higher than any of todays mountains, but millions of years of erosion have changed these mountains to rolling hills. The Canadian Shield was the first part of North America to be elevated above sea level and has remained almost wholly untouched by successive encroachments of the sea upon the continent. It is the Earths greatest area of exposed Archean rock, the metamorphic base rocks are mostly from the Precambrian Supereon, and have been repeatedly uplifted and eroded. Today it consists largely of an area of low relief 300 to 610 m above sea level with a few monadnocks, during the Pleistocene Epoch, continental ice sheets depressed the land surface, scooped out thousands of lake basins, and carried away much of the regions soil. When the Greenland section is included, the Shield is approximately circular, bounded on the northeast by the northeast edge of Greenland and it covers much of Greenland, Labrador, most of Quebec north of the St. In total, the area of the Shield covers approximately 8,000,000 km2. The underlying rock structure also includes Hudson Bay, the Canadian Shield is among the oldest on earth, with regions dating from 2.5 to 4.2 billion years. The multitude of rivers and lakes in the region is caused by the watersheds of the area being so young. It has some of the oldest volcanoes on the planet and it has over 150 volcanic belts whose bedrock ranges from 600 to 1200 million years old. Each belt probably grew by the coalescence of accumulations erupted from numerous vents, many of Canadas major ore deposits are associated with Precambrian volcanoes. The Sturgeon Lake Caldera in Kenora District, Ontario, is one of the worlds best preserved mineralized Neoarchean caldera complexes, the Canadian Shield also contains the Mackenzie dike swarm, which is the largest dike swarm known on Earth. Mountains have deep roots and float on the denser mantle much like an iceberg at sea, as mountains erode, their roots rise and are eroded in turn. The rocks that now form the surface of the Shield were once far below the Earths surface, the high pressures and temperatures at those depths provided ideal conditions for mineralization. Although these mountains are now eroded, many large mountains still exist in Canadas far north called the Arctic Cordillera. This is a vast deeply dissected mountain range, stretching from northernmost Ellesmere Island to the northernmost tip of Labrador, the ranges highest peak is Nunavuts Barbeau Peak at 2,616 metres above sea level
4.
Great Plains
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The region is known for supporting extensive cattle ranching and dry farming. The Canadian portion of the Plains is known as the Prairies, some geographers include some territory of northern Mexico in the Plains, but many stop at the Rio Grande. The term Great Plains is used in the United States to describe a sub-section of the even more vast Interior Plains physiographic division and it also has currency as a region of human geography, referring to the Plains Indians or the Plains States. There is no region referred to as the Great Plains in The Atlas of Canada, in terms of human geography, the term prairie is more commonly used in Canada, and the region is known as the Prairie Provinces or simply the Prairies. The region is about 500 mi east to west and 2,000 mi north to south, much of the region was home to American bison herds until they were hunted to near extinction during the mid/late 19th century. It has an area of approximately 500,000 sq mi, current thinking regarding the geographic boundaries of the Great Plains is shown by this map at the Center for Great Plains Studies, University of Nebraska–Lincoln. The term Great Plains, for the region west of about the 96th or 98th meridian, nevin Fennemans 1916 study, Physiographic Subdivision of the United States, brought the term Great Plains into more widespread usage. Before that the region was almost invariably called the High Plains, today the term High Plains is used for a subregion of the Great Plains. The Great Plains are the westernmost portion of the vast North American Interior Plains, during the Cretaceous Period, the Great Plains were covered by a shallow inland sea called the Western Interior Seaway. However, during the Late Cretaceous to the Paleocene, the seaway had begun to recede, leaving thick marine deposits. During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, traditionally, the spread of grasslands and the development of grazers have been strongly linked. The vast majority of animals became extinct in North America at the end of the Pleistocene. In general, the Great Plains have a variety of weather through the year, with very cold and harsh winters and very hot. Wind speeds are very high, especially in winter. Grasslands are among the least protected biomes, humans have converted much of the prairies for agricultural purposes or to create pastures. The Great Plains have dust storms mostly every year or so, the 100th meridian roughly corresponds with the line that divides the Great Plains into an area that receive 20 in or more of rainfall per year and an area that receives less than 20 in. The region is subjected to extended periods of drought, high winds in the region may then generate devastating dust storms
5.
Tallgrass prairie
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The tallgrass prairie is an ecosystem native to central North America. They were characteristically found in the central forest-grasslands transition, the tall grasslands, the upper Midwest forest-savanna transition. They flourished in areas with loess soils and moderate rainfall around 30 to 35 inches per year. To the east were the eastern savannas. In the northeast, where fire was infrequent and periodic windthrow represented the source of disturbance. In contrast, shortgrass prairie was typical in the western Great Plains, due to expansive agricultural land use, very little tallgrass prairie remains. Retreating glaciers deposited the parent material for soil in the form of till, i. e. unsorted sediment, wind-dropped loess and organic matter accumulated, resulting in deep levels of topsoil. Animals such as bison, elk, deer, and rabbits added nitrogen to the soil through urine, Prairie dogs, a ground squirrel-like rodent considered to be a keystone species, dug tunnels that aerated the soil and channeled water several feet below the surface. For 5,000 to 8,000 years, more than 240 million acres of prairie grasslands were a feature of the landscape. Between 1800 and 1930, the vast majority was destroyed, settlers transformed what they named the Great American Desert or The Inland Sea into farmland. Further, extensive tile drainage has changed the water content and hydrodynamics. Tallgrass prairie is capable of supporting significant biodiversity, parts of the ecoregion among the top ten ecoregions for reptiles, birds, butterflies, and tree species. Tallgrass species are found in the understory layer, oak and hickory tree species occur in some areas, but generally in moderate densities. The tallgrass prairie biome depends on fires, a form of wildfire. Tree seedlings and intrusive alien species without fire tolerance are eliminated by periodic fires, such fires may either be set by humans or started naturally by lightning. Technically, prairies have less than 5–11% tree cover, a grass-dominated plant community with 10–49% tree cover is a savanna. After the steel plow was invented by John Deere, this fertile soil became one of Americas most important resources, over 95% of the original tallgrass prairie is now farmland. In Oklahoma, the tallgrass prairie has been maintained by ranchers and they have reintroduced plains bison to the vast expanses of grass
6.
Great Lakes
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Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth, containing 21% of the worlds surface fresh water by volume. The total surface is 94,250 square miles, and the volume is 5,439 cubic miles. Due to their sea-like characteristics the five Great Lakes have also long been referred to as inland seas, Lake Superior is the second largest lake in the world by area, and Lake Michigan is the largest lake that is entirely within one country. The southern half of the Great Lakes is bordered by the Great Lakes Megalopolis, the lakes have been a major highway for transportation, migration and trade, and they are home to a large number of aquatic species. Many invasive species have been introduced due to trade, and some threaten the regions biodiversity, though the five lakes reside in separate basins, they form a single, naturally interconnected body of fresh water, within the Great Lakes Basin. The lakes form a chain connecting the interior of North America to the Atlantic Ocean. From the interior to the outlet at the Saint Lawrence River, water flows from Superior to Huron and Michigan, southward to Erie, the lakes drain a large watershed via many rivers, and are studded with approximately 35,000 islands. There are also several smaller lakes, often called inland lakes. The surface area of the five primary lakes combined is roughly equal to the size of the United Kingdom, while the area of the entire basin is about the size of the UK. Lake Michigan is the one of the Great Lakes that is located entirely within the United States. The lakes are divided among the jurisdictions of the Canadian province of Ontario and the U. S. states of Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, Pennsylvania, and New York. Both Ontario and Michigan include in their boundaries portions of four of the lakes, Ontario does not border Lake Michigan, New York and Wisconsins jurisdictions extend into two lakes, and the remaining states into one of the lakes. This designation, however, is not universal and those living on the shore of Lake Superior often refer to all the other lakes as the lower lakes, because they are farther south. This corresponds to thinking of Lakes Erie and Ontario as down south, vessels sailing north on Lake Michigan are considered upbound even though they are sailing toward its effluent current. The Chicago River and Calumet River systems connect the Great Lakes Basin to the Mississippi River System through man-made alterations, the St. Marys River, including the Soo Locks, connects Lake Superior to Lake Huron. The Straits of Mackinac connect Lake Michigan to Lake Huron, the St. Clair River connects Lake Huron to Lake St. Clair. The Detroit River connects Lake St. Clair to Lake Erie, the Niagara River, including Niagara Falls, connects Lake Erie to Lake Ontario. The Welland Canal, bypassing the Falls, connects Lake Erie to Lake Ontario, the Saint Lawrence River connects Lake Ontario to the Gulf of St. Lawrence, which connects to the Atlantic Ocean
7.
Appalachian Plateau
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The Appalachian Plateau is a series of rugged, high plains located on the western side of the Appalachian Highlands. The Appalachian Highlands are a range that run down the entire east coast of the United States. The Appalachian Plateau is the part of the Appalachian Mountains. The formation of the plateau began during the Paleozoic Era, regional uplift during this time caused the area to rise altogether without changing the topography of the land. The eastern side of the plateau appears as a mountain range and this false appearance is due to a very steep slope on the eastern side known as the Allegheny Front. The eastern edge is the highest part of the Appalachian Plateau, in Pennsylvania, the altitude ranges from 1,750 to 3,000 feet and continues to rise towards West Virginia, where the elevation is around 4,800 feet. From West Virginia to Tennessee the elevation lowers to 3,000 feet, on the western side of the plateau, the elevation is 900 feet in Ohio, increasing to about 2,000 feet in Kentucky. From Kentucky the elevation drops down to 500 feet in northwestern Alabama, the plateau has a slight slant towards the northwest making it higher on the eastern side. A large portion of the plateau is a coalfield that was formed approximately 320 million years ago during the Pennsylvanian Age, the plateau was subjected to glaciation during the Pleistocene ice age. As a result, the topography of this section of the plateau is flat in comparison to the rest of the province. This portion of the plateau is marked evidence of a glaciated past including bogs, lakes. The topography of the rest of the plateau was created mainly from stream erosion, the result is a rugged landscape, unlike many other plateaus, that includes many narrow stream valleys surrounded by steep ridges. A physiographic region is a portion of land that is grouped together by several factors. Each region has similar geology, topography, and groups of plants, there are eight physiographic regions in the United States. Each region is divided into provinces, there are 25 provinces in the United States, each region is then divided into sections, creating 85 different physio-graphic sections in the United States. The Appalachian Plateau is a province of the physio-graphic region Appalachian Highlands, each section is classified under the Appalachian Plateau province because of its similarities in geologic makeup, topography, and wildlife. Likewise, the Appalachian Plateau falls under the classification of Appalachian Highlands because of similar characteristics. The rock underlying the Appalachian Plateau consists of a base of Precambrian rock, on top of the basement is a thick layer, approximately 20,000 feet, of a mixture of Cambrian, Ordovician, and Middle Silurian rock
8.
Craton
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A craton is an old and stable part of the continental lithosphere, where the lithosphere consists of the Earths two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by sedimentary rock. They have a thick crust and deep roots that extend as much as several hundred kilometres into the Earths mantle. The term craton is used to distinguish the stable portion of the continental crust from regions that are geologically active. Cratons can be described as shields, in which the basement rock crops out at the surface, the word craton was first proposed by the Austrian geologist Leopold Kober in 1921 as Kratogen, referring to stable continental platforms, and orogen as a term for mountain or orogenic belts. Later authors shortened the term to kraton and then to craton. Cratons are subdivided geographically into geologic provinces, a geologic province is a spatial entity with common geologic attributes. A province may include a single dominant structural element such as a basin or a fold belt. Adjoining provinces may appear similar in structure but be considered due to differing histories. At that depth, craton roots extend into the asthenosphere, craton lithosphere is distinctly different from oceanic lithosphere because cratons have a neutral or positive buoyancy, and a low intrinsic isopycnic density. This low density offsets density increases due to contraction and prevents the craton from sinking into the deep mantle. Cratonic lithosphere is much older than oceanic lithosphere—up to 4 billion years versus 180 million years, rock fragments carried up from the mantle by magmas containing peridotite have been delivered to the surface as inclusions in subvolcanic pipes called kimberlites. These inclusions have densities consistent with composition and are composed of mantle material residual from high degrees of partial melt. Peridotite is strongly influenced by the inclusion of moisture, craton peridotite moisture content is unusually low, which leads to much greater strength. It also contains high percentages of low-weight magnesium instead of higher-weight calcium, peridotites are important for understanding the deep composition and origin of cratons because peridotite nodules are pieces of mantle rock modified by partial melting. Harzburgite peridotites represent the crystalline residues after extraction of melts of compositions like basalt, an associated class of inclusions called eclogites, consists of rocks corresponding compositionally to oceanic crust that has metamorphosed under deep mantle conditions. Isotopic studies reveal that many eclogite inclusions are samples of ancient oceanic crust subducted billions of years ago to depths exceeding 150 km into the deep kimberlite diamond areas and they remained fixed there within the drifting tectonic plates until carried to the surface by deep-rooted magmatic eruptions
9.
Trans-Hudson orogeny
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It gave rise to the Trans-Hudson orogen, or Trans-Hudson Orogen Transect, which is the largest Paleoproterozoic orogenic belt in the world. It consists of a network of belts that were formed by Proterozoic crustal accretion, the event occurred 2. 0-1.8 billion years ago. The Trans-Hudson orogen sutured together the Hearne-Rae, Superior, and Wyoming cratons to form the core of North America in a network of Paleoproterozoic orogenic belts. To the south, the orogen contributed to the subsurface Phanerozoic strata in Montana, the Trans-Hudson orogeny was the culminating event of the Paleoproterozoic Laurentian assembly, which occurred after the Wopmay orogeny. Similar to the Himalayas, the Trans-Hudson orogeny was also the result of continent-continent collision along a suture zone, only the roots of this mountain chain remain, but these can be seen in northeastern Saskatchewan and in the Black Hills of South Dakota. The Black Hills of South Dakota is one of the few remaining exposed portions of the Trans-Hudson orogenic belt. The peaks of the Black Hills are 3,000 to 4,000 feet above the surrounding plains and these central spires and peaks all are carved from granite and other igneous and metamorphic rocks that form the core of the uplift. The nature and timing of this portion of the THO event in southern Laurentia is poorly understood, based on geophysical evidence, this zone has been broadly interpreted to be the southern extension of the THO that was later truncated by the ~1.680 Ga. Marine evidence indicates that the area opened to form an ocean called the Manikewan Ocean. Faulting, sedimentary and igneous rocks all indicate that divergence formed a valley that continued to spread until it resulted in a passive margin in which there was no tectonic activity. Shallow marine deposits formed on the shelves, and oceanic crust formed on the margins of the continental cratons as the divergence continued. Eventually the divergence stopped, then reversed direction, and collision occurred between continental land masses, during the Wopmay orogeny, subduction occurred as oceanic crust of the Slave Craton was subducted beneath an eastward moving continental plate. Likewise, during the Trans-Hudson orogeny, rifting at first separated the Superior craton from the rest of the continent, then the Superior Craton reversed its direction and the ocean basin began to close. A subduction zone formed as the oceanic crust of the Superior Craton was subducted beneath the Hearne, volcanic arcs developed as the cratons collided, eventually resulting in the THO mountain building. The Reindeer zone to the north is a 500 km wide collage of Paleoproterozoic arc volcanic rocks, plutons, volcanogenic sediments, most of these rocks evolved in an oceanic to transitional, subduction-related arc setting, with increasing influence of Archean crustal components to the northwest. The zone overlies Archean basement exposed in structural window that are now recognized as the Sask craton, the Wathaman-Chipewyan batholith is an Andean-type continental-margin, magmatic arc emplaced 1. 86-1.85 Ga. The Flin Flon domain is in the center of the Trans-Hudson Suture Zone and it is west of the Superior Craton, south of the Kisseynew Domain, and east of the Glennie Domain. The Superior Boundary zone is a narrow, southeastern, ensialic foreland zone bordering Superior Craton, comprising the Thompson Belt, Split Lake Block, most of mined VMS deposits in the Flin Flon belt are associated with juvenile arc volcanic rocks providing a powerful focus for future explorations
