1.
Summit
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A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a maximum in elevation. The topographic terms acme, apex, peak, and zenith are synonymous, the UIAA definition is that a summit is independent if it has a prominence of 30 metres or more, it is a mountain if it has a prominence of at least 300 metres. This can be summarised as follows, A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top, Summit may also refer to the highest point along a line, trail, or route. In many parts of the western United States, the term refers to the highest point along a road, highway. For example, the highest point along Interstate 80 in California is referred to as Donner Summit while the highest point on Interstate 5 is Siskiyou Mountain Summit, geoid Hill List of highest mountains Maxima and minima Nadir Summit accordance Peak finder
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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
3.
Americas
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The Americas, also collectively called America, encompass the totality of the continents of North America and South America. Together they make up most of the land in Earths western hemisphere, along with their associated islands, they cover 8% of Earths total surface area and 28. 4% of its land area. The topography is dominated by the American Cordillera, a chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by river basins, such as the Amazon, St. Lawrence River / Great Lakes basin, Mississippi. Humans first settled the Americas from Asia between 42,000 and 17,000 years ago, a second migration of Na-Dene speakers followed later from Asia. The subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is regarded as the settlement by the indigenous peoples of the Americas. The first known European settlement in the Americas was by the Norse explorer Leif Ericson, however, the colonization never became permanent and was later abandoned. The voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European powers, diseases introduced from Europe and Africa devastated the indigenous peoples, and the European powers colonized the Americas. Mass emigration from Europe, including numbers of indentured servants. Decolonization of the Americas began with the American Revolution in 1776, the population is over 1 billion, with over 65% of them living in one of the three most populous countries. As of the beginning of the 2010s, the most populous urban agglomerations are Mexico City, New York, Sao Paulo, Los Angeles, Buenos Aires and Rio de Janeiro, all of them megacities. The name America was first recorded in 1507 in the Cosmographiae Introductio, apparently written by Matthias Ringmann and it first applied to both North and South America by Gerardus Mercator in 1538. Amerigen means land of Amerigo and derives from Amerigo and gen, America accorded with the feminine names of Asia, Africa, and Europa. When conceived as a continent, the form is generally the continent of America in the singular. However, without a context, singular America in English commonly refers to the United States of America. In some countries of the world, America is considered a continent encompassing the North America and South America subcontinents, the first inhabitants migrated into the Americas from Asia. Habitation sites are known in Alaska and the Yukon from at least 20,000 years ago, beyond that, the specifics of the Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are subject to ongoing research and discussion. Widespread habitation of the Americas occurred during the glacial maximum
4.
Mountain range
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A mountain range is a geographic area containing numerous geologically related mountains. A mountain system or system of ranges, sometimes is used to combine several geological features that are geographically related. Mountain ranges are usually segmented by highlands or mountain passes and valleys, individual mountains within the same mountain range do not necessarily have the same geologic structure or petrology. They may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, fold mountains, most geologically young mountain ranges on the Earths land surface are associated with either the Pacific Ring of Fire or the Alpide Belt. The Andes is 7,000 kilometres long and is considered the worlds longest mountain system. The Alpide belt includes Indonesia and southeast Asia, through the Himalaya, the belt also includes other European and Asian mountain ranges. The Himalayas contain the highest mountains in the world, including Mount Everest, mountain ranges outside of these two systems include the Arctic Cordillera, the Urals, the Appalachians, the Scandinavian Mountains, the Altai Mountains and the Hijaz Mountains. If the definition of a range is stretched to include underwater mountains. The mountain systems of the earth are characterized by a tree structure, the sub-range relationship is often expressed as a parent-child relationship. For example, the White Mountains of New Hampshire and the Blue Ridge Mountains are sub-ranges of the Appalachian Mountains, equivalently, the Appalachians are the parent of the White Mountains and Blue Ridge Mountains, and the White Mountains and the Blue Ridge Mountains are children of the Appalachians. The position of mountains influences climate, such as rain or snow, when air masses move up and over mountains, the air cools producing orographic precipitation. As the air descends on the side, it warms again and is drier. Often, a shadow will affect the leeward side of a range. Mountain ranges are constantly subjected to forces which work to tear them down. Erosion is at work while the mountains are being uplifted and long after until the mountains are reduced to low hills, rivers are traditionally believed to be the principle erosive factor on mountain ranges, with their ability of bedrock incision and sediment transport. The rugged topography of a range is the product of erosion. The basins adjacent to a mountain range are filled with sediments which are buried and turned into sedimentary rock. The early Cenozoic uplift of the Rocky Mountains of Colorado provides an example and this mass of rock was removed as the range was actively undergoing uplift
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Structural basin
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A structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat-lying strata. Structural basins are geological depressions, and are the inverse of domes, some elongated structural basins are also known as synclines. Basins may appear on a map as roughly circular or elliptical. Because the strata dip toward the center, the strata in a basin are progressively younger from the outside in. Basins are often large in extent, often hundreds of kilometers across. Structural basins are important sources of coal, petroleum, and groundwater. The Changing Earth, Exploring Geology and Evolution, 2nd ed. Belmont, Wadsworth Publishing Company,1997
6.
Plateau
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Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Magma rises from the mantle, causing the ground to swell upward, in way, large, flat areas of rock are uplifted. Plateaus can also be built up by lava spreading outward from cracks, plateaus can also be formed by the erosional processes of glaciers on mountain ranges, leaving them sitting between the mountain ranges. Water can also erode mountains and other landforms down into plateaus, volcanic plateaus are produced by volcanic activity. The Columbia Plateau in the northwestern United States is an example, dissected plateaus are highly eroded plateaus cut by rivers and broken by deep narrow valleys. Plateaus are classified according to their surrounding environment, intermontane plateaus are the highest in the world, bordered by mountains. The Tibetan Plateau is one such plateau, Piedmont plateaus are bordered on one side by mountains and on the other by a plain or a sea. The Piedmont Plateau of the Eastern United States between the Appalachian Mountains and the Atlantic Coastal Plain is an example, continental plateaus are bordered on all sides by plains or oceans, forming away from the mountains. The Tibetan plateau covers approximately 2,500,000 km2, the plateau is sufficiently high enough to reverse the Hadley cell convection cycles and to drive the monsoons of India towards the south. The second-highest plateau is the Deosai Plateau of the Deosai National Park at an elevation of 4,114 m. It is located in the Astore and Skardu districts of Gilgit-Baltistan, Deosai means the land of giants. The park protects an area of 3,000 km2 and it is known for its rich flora and fauna of the Karakoram-West Tibetan Plateau alpine steppe ecoregion. In spring it is covered by sweeps of wildflowers and a variety of butterflies. The highest point in Deosai is Deosai Lake, or Sheosar Lake from the Shina language meaning Blind lake near the Chilim Valley. The lake lies at an elevation of 4,142 m, one of the highest lakes in the world, and is 2.3 km long,1.8 km wide, and 40 m deep on average. Some other major plateaus in Asia are, Armenian Highlands, Iranian plateau, Anatolian Plateau, Mongolian Plateau, and the Deccan Plateau. This polar ice cap is so massive that the echolocation sound measurements of ice thickness have shown that parts of the Antarctic dry land surface have been pressed below sea level. Thus, if that same ice cap were removed, the large areas of the frozen white continent would be flooded by the surrounding Antarctic Ocean or Southern Ocean
7.
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
8.
Physical geography
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Physical geography is one of the two major sub-fields of geography. Geomorphology seeks to understand landform history and dynamics, and predict future changes through a combination of observation, physical experiment. Thus the field encompasses water in rivers, lakes, aquifers and to an extent glaciers, in which the field examines the process and dynamics involved in these bodies of water. Similar to most fields of physical geography it has sub-fields that examine the bodies of water or their interaction with other spheres e. g. limnology and ecohydrology. Glaciology is the study of glaciers and ice sheets, or more commonly the cryosphere or ice, glaciology groups the latter as continental glaciers and the former as alpine glaciers. Glaciology also has a vast array of sub-fields examining the factors and processes involved in ice sheets and glaciers e. g. snow hydrology, Biogeography is the science which deals with geographic patterns of species distribution and the processes that result in these patterns. The main stimulus for the field since its founding has been that of evolution, plate tectonics, climatology examines both the nature of micro and macro climates and the natural and anthropogenic influences on them. The field is also sub-divided largely into the climates of various regions, meteorology is the interdisciplinary scientific study of the atmosphere that focuses on weather processes and short term forecasting. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the eighteenth century, meteorological phenomena are observable weather events which illuminate and are explained by the science of meteorology. Pedology is the study of soils in their natural environment and it is one of two main branches of soil science, the other being edaphology. Pedology mainly deals with pedogenesis, soil morphology, soil classification, palaeogeography is a cross-disciplinary study that examines the preserved material in the stratigraphic record to determine the distribution of the continents through geologic time. Almost all the evidence for the positions of the continents comes from geology in the form of fossils or paleomagnetism, the use of this data has resulted in evidence for continental drift, plate tectonics, and supercontinents. This, in turn, has supported palaeogeographic theories such as the Wilson cycle, coastal geography is the study of the dynamic interface between the ocean and the land, incorporating both the physical geography and the human geography of the coast. It involves an understanding of coastal weathering processes, particularly wave action, sediment movement and weathering, coastal geography, although predominantly geomorphological in its research, is not just concerned with coastal landforms, but also the causes and influences of sea level change. Oceanography is the branch of geography that studies the Earths oceans. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean, Quaternary science is an inter-disciplinary field of study focusing on the Quaternary period, which encompasses the last 2.6 million years. The field was founded by the German geographer Carl Troll. Landscape ecology typically deals with problems in an applied and holistic context, geomatics is the field of gathering, storing, processing, and delivering geographic information, or spatially referenced information
9.
Geology of the Rocky Mountains
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The geology of the Rocky Mountains is that of a discontinuous series of mountain ranges with distinct geological origins. The rocky cores of the ranges are, in most places. In the south, a mountain range was formed 300 million years ago. The rocks of that range were reformed into the Rocky Mountains. The Rocky Mountains took shape during a period of plate tectonic activity that resulted in much of the rugged landscape of the western North America. The Laramide orogeny, about 80–55 million years ago, was the last of the three episodes and was responsible for raising the Rocky Mountains, subsequent erosion by glaciers has created the current form of the mountains. The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces, the oldest rock is Precambrian metamorphic rock that forms the core of the North American continent. There is also Precambrian sedimentary argillite, dating back to 1.7 billion years ago, during the Paleozoic, western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite. In the southern Rocky Mountains, near present-day Colorado, these rocks were disturbed by mountain building approximately 300 Ma. This mountain building produced the Ancestral Rocky Mountains, the uplift created two large mountainous islands, known to geologists as Frontrangia and Uncompahgria, located roughly in the current locations of the Front Range and the San Juan Mountains. They consisted largely of Precambrian metamorphic rock, forced upward through layers of the laid down in the shallow sea. The mountains eroded throughout the late Paleozoic and early Mesozoic, leaving deposits of sedimentary rock. Mesozoic deposition in the Rockies occurred in a mix of marine, transitional, by the close of the Mesozoic,10,000 to 15,000 feet of sediment accumulated in 15 recognized formations. The most extensive non-marine formations were deposited in the Cretaceous period when the part of the Western Interior Seaway covered the region. Terranes started to collide with the edge of North America in the Mississippian age. During the last half of the Mesozoic Era, much of todays California, British Columbia, Oregon, Western North America suffered the effects of repeated collision as the Kula and Farallon plates sank beneath the continental edge. Slivers of continental crust, carried along by subducting plates, were swept into the subduction zone. These terranes represent a variety of tectonic environments, magma generated above the subducting slab rose into the North American continental crust about 200 to 300 miles inland
10.
U.S. state
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A U. S. state is a constituent political entity of the United States of America. There are 50 states, which are together in a union with each other. Each state holds administrative jurisdiction over a geographic territory. Due to the shared sovereignty between each state and the government, Americans are citizens of both the federal republic and of the state in which they reside. State citizenship and residency are flexible, and no government approval is required to move between states, except for persons covered by certain types of court orders. States range in population from just under 600,000 to over 39 million, four states use the term commonwealth rather than state in their full official names. States are divided into counties or county-equivalents, which may be assigned some local authority but are not sovereign. County or county-equivalent structure varies widely by state, State governments are allocated power by the people through their individual constitutions. All are grounded in principles, and each provides for a government. States possess a number of powers and rights under the United States Constitution, Constitution has been amended, and the interpretation and application of its provisions have changed. The general tendency has been toward centralization and incorporation, with the government playing a much larger role than it once did. There is a debate over states rights, which concerns the extent and nature of the states powers and sovereignty in relation to the federal government. States and their residents are represented in the federal Congress, a legislature consisting of the Senate. Each state is represented in the Senate by two senators, and is guaranteed at least one Representative in the House, members of the House are elected from single-member districts. Representatives are distributed among the states in proportion to the most recent constitutionally mandated decennial census, the Constitution grants to Congress the authority to admit new states into the Union. Since the establishment of the United States in 1776, the number of states has expanded from the original 13 to 50, alaska and Hawaii are the most recent states admitted, both in 1959. The Constitution is silent on the question of states have the power to secede from the Union. Shortly after the Civil War, the U. S. Supreme Court, in Texas v. White, as a result, while the governments of the various states share many similar features, they often vary greatly with regard to form and substance
11.
Alaska
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Alaska is a U. S. state located in the northwest extremity of North America. To the north are the Chukchi and Beaufort seas–the southern parts of the Arctic Ocean, the Pacific Ocean lies to the south and southwest. Alaska is the largest state in the United States by area, the 3rd least populous, approximately half of Alaskas residents live within the Anchorage metropolitan area. Alaskas economy is dominated by the fishing, natural gas, military bases and tourism are also a significant part of the economy. The United States purchased Alaska from the Russian Empire on March 30,1867, the area went through several administrative changes before becoming organized as a territory on May 11,1912. It was admitted as the 49th state of the U. S. on January 3,1959, the name Alaska was introduced in the Russian colonial period when it was used to refer to the peninsula. It was derived from an Aleut, or Unangam idiom, which refers to the mainland of Alaska. Literally, it means object to which the action of the sea is directed, Alaska is the northernmost and westernmost state in the United States and has the most easterly longitude in the United States because the Aleutian Islands extend into the Eastern Hemisphere. Alaska is the only non-contiguous U. S. state on continental North America and it is technically part of the continental U. S. but is sometimes not included in colloquial use, Alaska is not part of the contiguous U. S. often called the Lower 48. The capital city, Juneau, is situated on the mainland of the North American continent but is not connected by road to the rest of the North American highway system. Alaskas territorial waters touch Russias territorial waters in the Bering Strait, as the Russian Big Diomede Island, Alaska has a longer coastline than all the other U. S. states combined. Alaska is the largest state in the United States by total area at 663,268 square miles, over twice the size of Texas, Alaska is larger than all but 18 sovereign countries. Counting territorial waters, Alaska is larger than the area of the next three largest states, Texas, California, and Montana. It is also larger than the area of the 22 smallest U. S. states. Also referred to as the Panhandle or Inside Passage, this is the region of Alaska closest to the rest of the United States, as such, this was where most of the initial non-indigenous settlement occurred in the years following the Alaska Purchase. The region is dominated by the Alexander Archipelago as well as the Tongass National Forest and it contains the state capital Juneau, the former capital Sitka, and Ketchikan, at one time Alaskas largest city. The Alaska Marine Highway provides a vital transportation link throughout the area. The Interior is the largest region of Alaska, much of it is uninhabited wilderness, Fairbanks is the only large city in the region
12.
Mexico
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Mexico, officially the United Mexican States, is a federal republic in the southern half of North America. It is bordered to the north by the United States, to the south and west by the Pacific Ocean, to the southeast by Guatemala, Belize, and the Caribbean Sea, and to the east by the Gulf of Mexico. Covering almost two million square kilometers, Mexico is the sixth largest country in the Americas by total area, Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana, pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its base in Mexico-Tenochtitlan, Three centuries later, this territory became Mexico following recognition in 1821 after the colonys Mexican War of Independence. The tumultuous post-independence period was characterized by instability and many political changes. The Mexican–American War led to the cession of the extensive northern borderlands, one-third of its territory. The Pastry War, the Franco-Mexican War, a civil war, the dictatorship was overthrown in the Mexican Revolution of 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the countrys current political system. Mexico has the fifteenth largest nominal GDP and the eleventh largest by purchasing power parity, the Mexican economy is strongly linked to those of its North American Free Trade Agreement partners, especially the United States. Mexico was the first Latin American member of the Organisation for Economic Co-operation and Development and it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts. By 2050, Mexico could become the fifth or seventh largest economy. The country is considered both a power and middle power, and is often identified as an emerging global power. Due to its culture and history, Mexico ranks first in the Americas. Mexico is a country, ranking fourth in the world by biodiversity. In 2015 it was the 9th most visited country in the world, Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus and the Pacific Alliance. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely, the Valley of Mexico, and its people, the Mexica and this became the future State of Mexico as a division of New Spain prior to independence. It is generally considered to be a toponym for the valley became the primary ethnonym for the Aztec Triple Alliance as a result. After New Spain won independence from Spain, representatives decided to name the new country after its capital and this was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan
13.
Pacific Coast Ranges
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The Pacific Coast Ranges, are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. The same term is used informally in Canada to refer to the Coast Mountains and adjoining inland ranges such as the Hazelton Mountains, the coastline is often dropping steeply into the sea with photogenic views. Along the British Columbia and Alaska coast, the mountains intermix with the sea in a maze of fjords. Off the Southern California coast the Channel Islands archipelago of the Santa Monica Mountains extends for 160 miles, on the West coast of North America, the coast ranges and the coastal plain form the margin. Most of the land is made of terranes that have accreted onto the margin. In the north, the belt is an accreted terrane. This belt extends from the Wrangellia Terrane in Alaska to the Chilliwack group of Canada, a rupture in Rodinia 750 million years ago formed a passive margin in the eastern Pacific Northwest. The breakup of Pangea 200 million years ago began the movement of the North American plate. As the continent drifted West, terranes were accreted onto the west coast, the timing of the accretion of the insular belt is uncertain, although the closure did not occur until at least 115 million years ago. Other Mesozoic terranes that accreted onto the continent include the Klamath Mountains, the Sierra Nevada,80 to 90 million years ago the subducting Farallon plate split and formed the Kula Plate to the North. This formed an area in what is now Northern California, where the plates converged forming a Mélange, North of this was the Columbia Embayment, where the continental margin was east of the surrounding areas. Many of the major batholiths date from the late Cretaceous, as the Laramide Orogeny ended around 48 million years ago, the accretion of the Siletzia terrane began in the Pacific Northwest. This began the activity in the Cascadia subduction zone, forming the modern Cascade Range. Events here may relate to the ignimbrite flare-up of the southern Basin, as extension in the Basin and Range Province slowed by a change in North American Plate movement circa 7 to 8 Million years ago, rifting began on the Gulf of California. Although many of the ranges do share a common history, the Pacific Coast Ranges province is not defined by geology. However, both are considered part of the Pacific Coast Ranges due to their proximity and similar economic, the Pacific Coast Ranges are home to the largest temperate-latitude icefields in the world. Formally unnamed icefields are not listed List of Pacific Coast Ranges topics Coast Range California Coast Ranges Coast Ranges United States physiographic regions
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Sierra Nevada (U.S.)
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The Sierra Nevada is a mountain range in the Western United States, between the Central Valley of California and the Basin and Range Province. The vast majority of the lies in the state of California. The Sierra runs 400 miles north-to-south, and is approximately 70 miles across east-to-west, the Sierra is home to three national parks, twenty wilderness areas, and two national monuments. These areas include Yosemite, Sequoia, and Kings Canyon National Parks, the character of the range is shaped by its geology and ecology. More than one hundred years ago during the Nevadan orogeny. The range started to uplift four M. A. ago, the uplift caused a wide range of elevations and climates in the Sierra Nevada, which are reflected by the presence of five life zones. Uplift continues due to faulting caused by forces, creating spectacular fault block escarpments along the eastern edge of the southern Sierra. The Sierra Nevada has a significant history, the California Gold Rush occurred in the western foothills from 1848 through 1855. Due to inaccessibility, the range was not fully explored until 1912, the Sierra Nevada lies in Central and Eastern California, with a very small but historically important spur extending into Nevada. West-to-east, the Sierra Nevadas elevation increases gradually from 1,000 feet in the Central Valley to an height of about 10,500 feet at its crest only 50–75 miles to the east. The east slope forms the steep Sierra Escarpment, unlike its surroundings, the range receives a substantial amount of snowfall and precipitation due to orographic lift. The Sierra Nevada stretches from the Susan River and Fredonyer Pass in the north to Tehachapi Pass in the south and it is bounded on the west by Californias Central Valley and on the east by the Basin and Range Province. The geographical boundary between the Sierra and the Cascades is virtually indistinguishable, with the Fredonyer Pass designation being traditional, physiographically, the Sierra is a section of the Cascade-Sierra Mountains province, which in turn is part of the larger Pacific Mountain System physiographic division. The range is drained on its western slope by the Central Valley watershed, the northern third of the western Sierra is part of the Sacramento River watershed, and the middle third is drained by the San Joaquin River. The eastern slope watershed of the Sierra is much narrower, its rivers flow out into the endorheic Great Basin of eastern California and western Nevada. Although none of the eastern rivers reach the sea, many of the streams from Mono Lake southwards are diverted into the Los Angeles Aqueduct which provides water to Southern California, the height of the mountains in the Sierra Nevada increases gradually from north to south. Between Fredonyer Pass and Lake Tahoe, the range from 5,000 feet to more than 9,000 feet. The crest near Lake Tahoe is roughly 9,000 feet high, farther south, the highest peak in Yosemite National Park is Mount Lyell
15.
Rocky Mountains
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The Rocky Mountains, commonly known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 3,000 miles from the northernmost part of British Columbia, in western Canada, to New Mexico, in the Southwestern United States. Within the North American Cordillera, the Rockies are somewhat distinct from the Pacific Coast Ranges, the Rocky Mountains were initially formed from 80 million to 55 million years ago during the Laramide orogeny, in which a number of plates began to slide underneath the North American plate. The angle of subduction was shallow, resulting in a belt of mountains running down western North America. Since then, further tectonic activity and erosion by glaciers have sculpted the Rockies into dramatic peaks, at the end of the last ice age, humans started to inhabit the mountain range. The first mention of their present name by a European was in the journal of Jacques Legardeur de Saint-Pierre in 1752, the Rocky Mountains are commonly defined as stretching from the Liard River in British Columbia south to the Rio Grande in New Mexico. The United States definition of the Rockies includes the Cabinet and Salish Mountains of Idaho and their counterparts north of the Kootenai River, the Columbia Mountains, are considered a separate system in Canada, lying to the west of the huge Rocky Mountain Trench. This runs the length of British Columbia from its beginnings in the middle Flathead River valley in western Montana to the bank of the Liard River. The Rockies vary in width from 70 to 300 miles, also west of the Rocky Mountain Trench, farther north and facing the Muskwa Range across the trench, are the Stikine Ranges and Omineca Mountains of the Interior Mountains system of British Columbia. A small area east of Prince George, British Columbia on the side of the Trench. In Canada geographers define three main groups of ranges, the Continental Ranges, Hart Ranges and Muskwa Ranges, the Muskwa and Hart Ranges together comprise what is known as the Northern Rockies. The western edge of the Rockies includes ranges such as the Wasatch near Salt Lake City, the Great Basin and Columbia River Plateau separate these sub-ranges from distinct ranges further to the west, most prominent among which are the Sierra Nevada, Cascade Range and Coast Mountains. The Rocky Mountain System within the United States is a United States physiographic region, the Rocky Mountains are notable for containing the highest peaks in central North America. The ranges highest peak is Mount Elbert located in Colorado at 14,440 feet above sea level, Mount Robson in British Columbia, at 12,972 feet, is the highest peak in the Canadian Rockies. The Continental Divide of the Americas is located in the Rocky Mountains, triple Divide Peak in Glacier National Park is so named because water that falls on the mountain reaches not only the Atlantic and Pacific, but Hudson Bay as well. Farther north in Alberta, the Athabasca and other rivers feed the basin of the Mackenzie River, see Rivers of the Rocky Mountains for a list of rivers. Human population is not very dense in the Rocky Mountains, with an average of four people per square kilometer, however, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The 40-year statewide increases in range from 35% in Montana to about 150% in Utah
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Orogeny
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An Orogeny is an event that leads to a large structural deformation of the Earths lithosphere due to the interaction between tectonic plates. Orogens or orogenic belts develop when a plate is crumpled and is pushed upwards to form mountain ranges. Orogeny is the mechanism by which mountains are built on continents. The word orogeny comes from Ancient Greek, though it was used before him, the term was employed by the American geologist G. K. Gilbert in 1890 to describe the process of mountain building as distinguished from epeirogeny. Formation of an orogen is accomplished in part by the processes of subduction or convergence of two or more continents. Orogeny usually produces long arcuate structures, known as orogenic belts, generally, orogenic belts consist of long parallel strips of rock exhibiting similar characteristics along the length of the belt. Orogenic belts are associated with zones, which consume crust, produce volcanoes. Geologists attribute the arcuate structure to the rigidity of the descending plate and these island arcs may be added to a continent during an orogenic event. The processes of orogeny can take tens of millions of years, frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. Orogenic processes may push deeply buried rocks to the surface, sea-bottom and near-shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, very high mountains can result, an orogenic event may be studied, as a tectonic structural event, as a geographical event, and as a chronological event. The foreland basin forms ahead of the orogen due mainly to loading and resulting flexure of the lithosphere by the mountain belt. The basin migrates with the front and early deposited foreland basin sediments become progressively involved in folding and thrusting. Sediments deposited in the basin are mainly derived from the erosion of the actively uplifting rocks of the mountain range. The fill of many such shows an change in time from deepwater marine through shallow water to continental sediments. Although orogeny involves plate tectonics, the tectonic forces result in a variety of associated phenomena, including magmatism, metamorphism, crustal melting, what exactly happens in a specific orogen depends upon the strength and rheology of the continental lithosphere, and how these properties change during orogenesis. In addition to orogeny, the orogen is subject to other processes, for example, the Caledonian Orogeny refers to the Silurian and Devonian events that resulted from the collision of Laurentia with Eastern Avalonia and other former fragments of Gondwana. The Caledonian Orogen resulted from events and various others that are part of its peculiar orogenic cycle
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Plate tectonics
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The theoretical model builds on the concept of continental drift developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s, the lithosphere, which is the rigid outermost shell of a planet, is broken up into tectonic plates. The Earths lithosphere is composed of seven or eight major plates, where the plates meet, their relative motion determines the type of boundary, convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The relative movement of the plates typically ranges from zero to 100 mm annually, tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle, the material lost is balanced by the formation of new crust along divergent margins by seafloor spreading. In this way, the surface of the lithosphere remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle, earlier theories, since disproven, proposed gradual shrinking or gradual expansion of the globe. Tectonic plates are able to move because the Earths lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the ridge and drag, with downward suction. Another explanation lies in the different forces generated by forces of the Sun. The relative importance of each of these factors and their relationship to other is unclear. The outer layers of the Earth are divided into the lithosphere and asthenosphere and this is based on differences in mechanical properties and in the method for the transfer of heat. Mechanically, the lithosphere is cooler and more rigid, while the asthenosphere is hotter, in terms of heat transfer, the lithosphere loses heat by conduction, whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, Plate motions range up to a typical 10–40 mm/year, to about 160 mm/year. The driving mechanism behind this movement is described below, tectonic lithosphere plates consist of lithospheric mantle overlain by either or both of two types of crustal material, oceanic crust and continental crust. Average oceanic lithosphere is typically 100 km thick, its thickness is a function of its age, as passes, it conductively cools
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Lithosphere
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A lithosphere is the rigid, outermost shell of a terrestrial-type planet or natural satellite that is defined by its rigid mechanical properties. On Earth, it is composed of the crust and the portion of the mantle that behaves elastically on time scales of thousands of years or greater. The outermost shell of a planet, the crust, is defined on the basis of its chemistry. Earths lithosphere includes the crust and the uppermost mantle, which constitute the hard, the lithosphere is subdivided into tectonic plates. The uppermost part of the lithosphere that chemically reacts to the atmosphere, hydrosphere and biosphere through the forming process is called the pedosphere. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, the study of past and current formations of landscapes is called geomorphology. The concept of the lithosphere as Earth’s strong outer layer was described by A. E. H, love in his 1911 monograph Some problems of Geodynamics and further developed by Joseph Barrell, who wrote a series of papers about the concept and introduced the term lithosphere. The concept was based on the presence of significant gravity anomalies over continental crust and these ideas were expanded by Reginald Aldworth Daly in 1940 with his seminal work Strength and Structure of the Earth and have been broadly accepted by geologists and geophysicists. The temperature at which olivine begins to deform viscously is often used to set this isotherm because olivine is generally the weakest mineral in the upper mantle, the mantle part of the lithosphere consists largely of peridotite. The crust is distinguished from the mantle by the change in chemical composition that takes place at the Moho discontinuity. Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle and is denser than continental lithosphere, oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge. This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick, the thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time. H ∼2 κ t Here, h is the thickness of the mantle lithosphere, κ is the thermal diffusivity for silicate rocks. The age is equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge. Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years and this is because the chemically differentiated oceanic crust is lighter than asthenosphere, but thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones, geoscientists can directly study the nature of the subcontinental mantle by examining mantle xenoliths brought up in kimberlite, lamproite, and other volcanic pipes. The histories of these xenoliths have been investigated by many methods, such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite the mantle flow that accompanies plate tectonics. Cryosphere Geosphere Kola Superdeep Borehole Plate tectonics Solid Earth Chernicoff, Stanley, Whitney, earths Crust, Lithosphere and Asthenosphere Crust and Lithosphere
19.
Laramide orogeny
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The Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous,70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, the Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The phenomenon is named for the Laramie Mountains of eastern Wyoming, the Laramide orogeny is sometimes confused with the Sevier orogeny, which partially overlapped it in time and space. The orogeny is commonly attributed to events off the west coast of North America, most hypotheses propose that oceanic crust was undergoing flat-slab subduction, i. e. One cause for shallow subduction may have been a rate of plate convergence. Another proposed cause was subduction of thickened oceanic crust, magmatism associated with subduction occurred not near the plate edges, but far to the east, called the Coast Range Arc. Geologists call such a lack of volcanic activity near a subduction zone a magmatic null and this particular null may have occurred because the subducted slab was in contact with relatively cool continental lithosphere, not hotter asthenosphere. One result of angle of subduction and the drag that it caused was a broad belt of mountains. Part of the proto-Rocky Mountains would be modified by extension to become the Basin. According to paleontologist Thomas M. Lehman, the Laramide orogeny triggered the most dramatic event that affected Late Cretaceous dinosaur communities in North America prior to their extinction, the Laramide orogeny produced intermontane structural basins and adjacent mountain blocks by means of deformation. This style of deformation is typical of continental plates adjacent to convergent margins of long duration that have not sustained continent/continent collisions and this tectonic setting produces a pattern of compressive uplifts and basins, with most of the deformation confined to block edges. Twelve kilometers of structural relief between basins and adjacent uplifts is not uncommon, the basins contain several thousand meters of Paleozoic and Mesozoic sedimentary rocks that predate the Laramide orogeny. As much as 5,000 meters of Cretaceous and Cenozoic sediments filled these orogenically-defined basins, deformed Paleocene and Eocene deposits record continuing orogenic activity. During the Laramide orogeny, basin floors and mountain summits were much closer to sea level than today, after the seas retreated from the Rocky Mountain region, floodplains, swamps, and vast lakes developed in the basins. Drainage systems imposed at that time persist today, since the Oligocene, episodic epeirogenic uplift gradually raised the entire region, including the Great Plains, to present elevations. Topographically, the basin floors resemble the surface of the western Great Plains, at most boundaries, Paleozoic through Paleogene units dip steeply into the basins off uplifted blocks cored by Precambrian rocks. The eroded steeply dipping units form hogbacks and flatirons, many of the boundaries are thrust or reverse faults. Although other boundaries appear to be monoclinal flexures, faulting is suspected at depth, most bounding faults show evidence of at least two episodes of Laramide movement, suggesting both thrust and strike-slip types of displacement
20.
Topography
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Topography is the study of the shape and features of the surface of the Earth and other observable astronomical objects including planets, moons, and asteroids. The topography of an area could refer to the shapes and features themselves. This field of geoscience and planetary science is concerned with detail in general, including not only relief but also natural and artificial features. This meaning is common in the United States, where topographic maps with elevation contours have made topography synonymous with relief. The older sense of topography as the study of place still has currency in Europe, topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms. This is also known as geomorphometry, in modern usage, this involves generation of elevation data in digital form. It is often considered to include the representation of the landform on a map by a variety of techniques, including contour lines, hypsometric tints. The term topography originated in ancient Greece and continued in ancient Rome, the word comes from the Greek τόπος and -γραφία. In classical literature this refers to writing about a place or places, in Britain and in Europe in general, the word topography is still sometimes used in its original sense. Detailed military surveys in Britain were called Ordnance Surveys, and this term was used into the 20th century as generic for topographic surveys, the earliest scientific surveys in France were called the Cassini maps after the family who produced them over four generations. The term topographic surveys appears to be American in origin, the earliest detailed surveys in the United States were made by the “Topographical Bureau of the Army, ” formed during the War of 1812, which became the Corps of Topographical Engineers in 1838. In the 20th century, the term started to be used to describe surface description in other fields where mapping in a broader sense is used. An objective of topography is to determine the position of any feature or more generally any point in terms of both a horizontal coordinate system such as latitude, longitude, and altitude, identifying features, and recognizing typical landform patterns are also part of the field. There are a variety of approaches to studying topography, which method to use depend on the scale and size of the area under study, its accessibility, and the quality of existing surveys. Work on one of the first topographic maps was begun in France by Giovanni Domenico Cassini, in areas where there has been an extensive direct survey and mapping program, the compiled data forms the basis of basic digital elevation datasets such as USGS DEM data. This data must often be cleaned to eliminate discrepancies between surveys, but it forms a valuable set of information for large-scale analysis. The original American topographic surveys involved not only recording of relief, remote sensing is a general term for geodata collection at a distance from the subject area. Besides their role in photogrammetry, aerial and satellite imagery can be used to identify and delineate terrain features, certainly they have become more and more a part of geovisualization, whether maps or GIS systems
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Eocene
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The Eocene Epoch, lasting from 56 to 33.9 million years ago, is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. As with other periods, the strata that define the start and end of the epoch are well identified. The name Eocene comes from the Ancient Greek ἠώς and καινός, the Eocene epoch is conventionally divided into early, middle, and late subdivisions. The corresponding rocks are referred to as lower, middle, the Ypresian stage constitutes the lower, the Priabonian stage the upper, and the Lutetian and Bartonian stages are united as the middle Eocene. The Eocene Epoch contained a variety of different climate conditions that includes the warmest climate in the Cenozoic Era. During this period of time, little to no ice was present on Earth with a difference in temperature from the equator to the poles. Following the maximum was a descent into an icehouse climate from the Eocene Optimum to the Eocene-Oligocene transition at 34 million years ago. During this decrease ice began to reappear at the poles, greenhouse gases, in particular carbon dioxide and methane, played a significant role during the Eocene in controlling the surface temperature. For the early Eocene there is discussion on how much carbon dioxide was in the atmosphere. This is due to numerous proxies representing different atmospheric carbon dioxide content, for contrast, today the carbon dioxide levels are at 400 ppm or 0. 04%. At about the beginning of the Eocene Epoch the amount of oxygen in the atmosphere more or less doubled. During the early Eocene, methane was another gas that had a drastic effect on the climate. In comparison to carbon dioxide, methane has much effect on temperature as methane is ~34 times more effective per molecule than carbon dioxide on a 100-year scale. Most of the methane released to the atmosphere during this period of time would have been from wetlands, swamps, the atmospheric methane concentration today is 0. 000179% or 1.79 ppmv. Due to the climate and sea level rise associated with the early Eocene, more wetlands, more forests. Comparing the early Eocene production of methane to current levels of atmospheric methane, biogenic production of methane produces carbon dioxide and water vapor along with the methane, as well as yielding infrared radiation
22.
Oligocene
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The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start. The name Oligocene comes from the Ancient Greek ὀλίγος and καινός, the Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period, the Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included an expansion of grasslands. By contrast, the Oligocene–Miocene boundary is not set at an easily identified worldwide event, Oligocene faunal stages from youngest to oldest are, The Paleogene Period general temperature decline is interrupted by an Oligocene 7-million-year stepwise climate change. A deeper 8.2 °C,400, 000-year temperature depression leads the 2 °C, the stepwise climate change began 32.5 Ma and lasted through to 25.5 Ma, as depicted in the PaleoTemps chart. The Oligocene climate change was a increase in ice volume. The 7-million-year depression abruptly terminated within 1–2 million years of the La Garita Caldera eruption at 28–26 Ma, a deep 400, 000-year glaciated Oligocene Miocene boundary event is recorded at McMurdo Sound and King George Island. During this epoch, the continued to drift toward their present positions. Antarctica became more isolated and finally developed an ice cap, a brief marine incursion marks the early Oligocene in Europe. Marine fossils from the Oligocene are rare in North America, there appears to have been a land bridge in the early Oligocene between North America and Europe, since the faunas of the two regions are very similar. Sometime during the Oligocene, South America was finally detached from Antarctica and it also allowed the Antarctic Circumpolar Current to flow, rapidly cooling the Antarctic continent. Angiosperms continued their expansion throughout the world as tropical and sub-tropical forests were replaced by deciduous forests. Open plains and deserts became more common and grasses expanded from their habitat in the Eocene moving out into open tracts. However, even at the end of the period, grass was not quite enough for modern savannas. In North America, subtropical species dominated with cashews and lychee trees present, and temperate trees such as roses, beeches, the legumes spread, while sedges, bulrushes, and ferns continued their ascent. Even more open landscapes allowed animals to grow to larger sizes than they had earlier in the Paleocene epoch 30 million years earlier, marine faunas became fairly modern, as did terrestrial vertebrate fauna on the northern continents
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Southeast Alaska
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The majority of Southeast Alaskas area is part of the Tongass National Forest, the United States largest national forest. In many places, the border runs along the crest of the Boundary Ranges of the Coast Mountains. The region is noted for its scenery and mild rainy climate, Southeast Alaska is the northern terminus of the Inside Passage, a protected waterway of convoluted passages between islands and fjords, beginning in Puget Sound in Washington state. This was an important travel corridor for Tlingit and Haida Native peoples, in modern times it is an important route for Alaska Marine Highway ferries as well as cruise ships. Southeast Alaska has an area of 35,138 square miles comprising seven entire boroughs. Although it has only 6.14 percent of Alaskas land area, it is larger than the state of Maine, the Southeast Alaskan coast is roughly as long as the west coast of Canada. The 2010 census population of Southeast was 71,616 inhabitants, the largest islands are, from North to South, Chichagof Island, Admiralty Island, Baranof Island, Kupreanof Island, Revillagigedo Island and Prince of Wales Island. Major bodies of water of Southeast Alaska include Glacier Bay, Lynn Canal, Icy Strait, Chatham Strait, Stephens Passage, Frederick Sound, Sumner Strait, and Clarence Strait. On August 20,1902, President Theodore Roosevelt established the Alexander Archipelago Forest Reserve, Glacier Bay National Park and Preserve Klondike Gold Rush National Historical Park Sitka National Historical Park Wrangell-St. The most common species are sitka spruce and western hemlock. Major cities are Juneau, Ketchikan, and Sitka, other towns are Petersburg, Wrangell, Metlakatla, Haines, Hoonah, Angoon, Kake, Craig, Klawock, Thorne Bay, Yakutat, Skagway, and Gustavus. This region is home to the easternmost town in Alaska. This area is the homeland of the Tlingit, and home of a historic settling of Haida as well as a modern settlement of Tsimshian. The region is connected to Seattle and the American Pacific Northwest economically and culturally. In modern times, southeastern Alaskans can often be identified by their choices, notably Xtratuf boots. Major industries in Southeast Alaska include commercial fishing and tourism and its members include Alcan Forest Products and Viking Lumber, which had been founded in Maine. Debates over whether to expand logging in the federally owned Tongass are not uncommon, mining remains important in the northern area with the Juneau mining district and Admiralty mining district hosting active mines as of 2015. Gold was discovered in 1880 and played an important part in the history of the region
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Alexander Archipelago
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The Alexander Archipelago is a 300 miles long archipelago, or group of islands, of North America off the southeastern coast of Alaska. It contains about 1,100 islands, which are the tops of the coastal mountains that rise steeply from the Pacific Ocean. Deep channels and fjords separate the islands and cut them off from the mainland, the northern part of the Inside Passage is sheltered by the islands as it winds its way among them. The islands have irregular, steep coasts and dense evergreen and temperate rain forests, the vast majority of the islands are part of the Tongass National Forest. All the islands are rugged, densely forested, and have an abundance of wildlife, the Tlingit and Kaigani Haida people are native to the area. The Tsimshian people found on Annette Island are not originally from the area, ketchikan on Revillagigedo Island and Sitka on Baranof Island are the largest towns on the islands. The most populous neighborhoods of the largest town in the region, Juneau, are on the mainland, though portions of the city lie on Douglas Island. Tourism, fishing, and logging are the industries of the islands. In 1774 Juan José Pérez Hernández sighted the south coast of Dall Island, in 1792 Jacinto Caamaño sighted Revillagigedo Island and the Gravina Islands, discovering Clarence Strait. An 1844 Russian chart shows Kupreanof separated from Mitkof Island and Etolin, Wrangell, Woronkofski, the archipelago was a locus of the Maritime Fur Trade during the early 19th century. Control of the islands passed from Russia to the United States with the Alaska Purchase in 1867, according to Donald Orths Dictionary of Alaska Place Names, the Alexander Archipelago received its name from the U. S. Coast and Geodetic Survey in 1867. The island chain is named for Tsar Alexander II of Russia, on an 1860 map of Russian America, the island group is called the King George III Archipelago. Alexander Archipelago Wolf Catherine Island British Columbia Coast Boundary Ranges Bell Island Kadin Island Alexander Archipelago
25.
Coast Mountains
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The mountain ranges name derives from its proximity to the sea coast, and is often referred to as the Coast Range. The range includes volcanic and non-volcanic mountains and the ice fields of the Pacific and Boundary Ranges. The Coast Mountains are approximately 1,600 kilometres long and average 300 kilometres in width, covered in dense temperate rainforest on its western exposures, the range rises to heavily glaciated peaks, including the largest temperate-latitude ice fields in the world. On its eastern flanks, the tapers to the dry Interior Plateau. The Coast Mountains are part of the Pacific Ring of Fire—the ring of volcanoes, the Coast Mountains consists of three subdivisions known as the Pacific Ranges, the Kitimat Ranges, and the Boundary Ranges. The Pacific Ranges are the southernmost subdivision of the Coast Mountains, included in this subdivision is four of the five major coastal icecaps in the southern Coast Mountains. These are the largest temperate-latitude icecaps in the world and fuel a number of major rivers, other than logging and a large ski resort at the resort town of Whistler, most of the land in the range is completely undeveloped. Mount Waddington, the highest mountain of the Coast Mountains, lies in the Waddington Range of the Pacific Ranges, just north of the Pacific Ranges lies the central subdivision known as the Kitimat Ranges. This subdivision extends from the Bella Coola River and Burke Channel in the south to the Nass River in the north, the third and northernmost subdivision of the Coast Mountains is the Boundary Ranges, extending from the Nass River in the south to the Kelsall River in the north. This precipitation is among the heaviest in North America, the eastern slopes are relatively dry and less steep and protect the British Columbia Interior from the Pacific weather systems, resulting in dry warm summers and dry cold winters. Beyond the eastern slopes is a 154,635 km2 plateau occupying the southern, included within the Interior Plateau is a coalescing series of layered flood basalt lava flows. These sequences of fluid volcanic rock cover about 25,000 km2 of the Interior Plateau and have a volume of about 1,800 km3, the Coast Mountains consists of deformed igneous and metamorphosed structurally complex pre-Tertiary rocks. These originated in locations around the globe, the area is built of several different terranes of different ages with a broad range of tectonic origins. Further north the northwesterly structural trend of the Coast Mountains lies partly in a continental rift responsible for the creation of several volcanoes. These volcanoes form part of the Northern Cordilleran Volcanic Province, the most volcanically active area in Canada, the first event began 130 million years ago when a group of active volcanic islands approached a pre-existing continental margin and coastline of North America. This subduction zone eventually jammed and shut down completely 115 million years ago, ending the Omineca Arc, compression resulting from this collision crushed, fractured and folded rocks along the old continental margin. The Insular Belt then welded onto the continental margin by magma that eventually cooled to create a large mass of igneous rock. This large mass of rock is the largest granite outcropping in North America
26.
Columbia Mountains
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The Columbia Mountains are a group of mountain ranges along the upper Columbia River in southeastern British Columbia, and also in Montana, Idaho and Washington. The mountain range covers 135,952 km², the range is bounded by the Rocky Mountain Trench on the east, and the Kootenay River on the south, their western boundary is the edge of the Interior Plateau. Mount Sir Sandford is the highest mountain in the range, reaching 3,519 metres, where the Columbia Mountains meet the Interior Plateau there are intermediary areas known as highlands - the Quesnel Highland, the Shuswap Highland, and the Okanagan Highland. These are listed here but are considered to be part of the Interior Plateau. Physiographically, they are a province of the larger Rocky Mountain System physiographic division. The following mountains are the 10 highest mountains contained within the Columbian Mountains, Columbia Mountains on Canadian Mountain Encyclopedia
27.
Canadian Rockies
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The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains. They are the part of the Canadian Cordillera, which is a system of multiple ranges of mountains which runs from the Canadian Prairies to the Pacific Coast. The southern end borders Idaho and Montana of the USA, in geographic terms the boundary is at the Canada/US border, but in geological terms it might be considered to be at Marias Pass in northern Montana. The northern end is at the Liard River in northern British Columbia, the Canadian Rockies have numerous high peaks and ranges, such as Mount Robson and Mount Columbia. The Canadian Rockies are composed of shale and limestone, much of the range is protected by national and provincial parks, several of which collectively comprise a World Heritage Site. The Canadian Rockies are the easternmost part of the Canadian Cordillera and they form part of the American Cordillera, an essentially continuous sequence of mountain ranges that runs all the way from Alaska to the very tip of South America. The Cordillera in turn are the part of the Pacific Ring of Fire that runs all the way around the Pacific Ocean. The Canadian Rockies are bounded on the east by the Canadian Prairies, on the west by the Rocky Mountain Trench, contrary to popular misconception, the Rockies do not extend north into Yukon or Alaska, or west into central British Columbia. North of the Liard River, the Mackenzie Mountains, which are a mountain range. The mountain ranges to the west of the Rocky Mountain Trench in southern British Columbia are called the Columbia Mountains, and are not considered to be part of the Rockies by Canadian geologists. Mount Robson is the highest peak in the Canadian Rockies, but not the highest in British Columbia, since there are higher mountains in the Coast Mountains. Its base is only 985 m above sea level, meaning it has a vertical relief of 2,969 m or nearly 10,000 feet. In addition, it rises the 3 km to its summit in a distance of only 4 km from its base at Kinney Lake, climbing Mount Robson is a challenge suitable for experienced and well-prepared mountaineers, and usually requires a week on the mountain. Mount Columbia is the second-highest peak in the Canadian Rockies, and is the highest mountain in Alberta, there is a non-technical route to the top involving only kicking steps in the snow, but the approach is across the Columbia Icefield and requires glacier travel and crevasse rescue knowledge. It is normally done in two days, with a night at camp, but some strong skiers have done it from the highway in a day. On the other hand, many others have been stuck in their tents for days waiting for the weather to clear. From the same camp as for Mount Columbia, it is possible to ascend a number of other high peaks in the area, including North Twin, South Twin, Kitchener, Stutfield. Snow Dome is not a peak by Rockies standards
28.
San Francisco
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San Francisco, officially the City and County of San Francisco, is the cultural, commercial, and financial center of Northern California. It is the birthplace of the United Nations, the California Gold Rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time. San Francisco became a consolidated city-county in 1856, after three-quarters of the city was destroyed by the 1906 earthquake and fire, San Francisco was quickly rebuilt, hosting the Panama-Pacific International Exposition nine years later. In World War II, San Francisco was a port of embarkation for service members shipping out to the Pacific Theater. Politically, the city votes strongly along liberal Democratic Party lines, San Francisco is also the headquarters of five major banking institutions and various other companies such as Levi Strauss & Co. Dolby, Airbnb, Weebly, Pacific Gas and Electric Company, Yelp, Pinterest, Twitter, Uber, Lyft, Mozilla, Wikimedia Foundation, as of 2016, San Francisco is ranked high on world liveability rankings. The earliest archaeological evidence of habitation of the territory of the city of San Francisco dates to 3000 BC. Upon independence from Spain in 1821, the became part of Mexico. Under Mexican rule, the system gradually ended, and its lands became privatized. In 1835, Englishman William Richardson erected the first independent homestead, together with Alcalde Francisco de Haro, he laid out a street plan for the expanded settlement, and the town, named Yerba Buena, began to attract American settlers. Commodore John D. Sloat claimed California for the United States on July 7,1846, during the Mexican–American War, montgomery arrived to claim Yerba Buena two days later. Yerba Buena was renamed San Francisco on January 30 of the next year, despite its attractive location as a port and naval base, San Francisco was still a small settlement with inhospitable geography. The California Gold Rush brought a flood of treasure seekers, with their sourdough bread in tow, prospectors accumulated in San Francisco over rival Benicia, raising the population from 1,000 in 1848 to 25,000 by December 1849. The promise of fabulous riches was so strong that crews on arriving vessels deserted and rushed off to the gold fields, leaving behind a forest of masts in San Francisco harbor. Some of these approximately 500 abandoned ships were used at times as storeships, saloons and hotels, many were left to rot, by 1851 the harbor was extended out into the bay by wharves while buildings were erected on piles among the ships. By 1870 Yerba Buena Cove had been filled to create new land, buried ships are occasionally exposed when foundations are dug for new buildings. California was quickly granted statehood in 1850 and the U. S. military built Fort Point at the Golden Gate, silver discoveries, including the Comstock Lode in Nevada in 1859, further drove rapid population growth. With hordes of fortune seekers streaming through the city, lawlessness was common, and the Barbary Coast section of town gained notoriety as a haven for criminals, prostitution, entrepreneurs sought to capitalize on the wealth generated by the Gold Rush
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California
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California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
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Denver
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Denver, officially the City and County of Denver, is the capital and most populous municipality of the U. S. state of Colorado. Denver is in the South Platte River Valley on the edge of the High Plains just east of the Front Range of the Rocky Mountains. The Denver downtown district is immediately east of the confluence of Cherry Creek with the South Platte River, Denver is nicknamed the Mile-High City because its official elevation is exactly one mile above sea level, making it the highest major city in the United States. The 105th meridian west of Greenwich, the reference for the Mountain Time Zone. Denver is ranked as a Beta- world city by the Globalization and World Cities Research Network. With a 2015 estimated population of 682,545, Denver ranks as the 19th-most populous U. S. city, and with a 2. 8% increase in 2015, the city is also the fastest-growing major city in the United States. The 10-county Denver-Aurora-Lakewood, CO Metropolitan Statistical Area had an estimated 2015 population of 2,814,330 and ranked as the 19th most populous U. S. metropolitan statistical area. The 12-city Denver-Aurora, CO Combined Statistical Area had an estimated 2015 population of 3,418,876, which ranks as the 16th most populous U. S. metropolitan area. Denver is the most populous city of the 18-county Front Range Urban Corridor, Denver is the most populous city within a 500-mile radius and the second-most populous city in the Mountain West after Phoenix, Arizona. In 2016, Denver was named the best place to live in the USA by U. S. News & World Report and this was the first historical settlement in what was later to become the city of Denver. The site faded quickly, however, and by the summer of 1859 it was abandoned in favor of Auraria, Larimer named the townsite Denver City to curry favor with Kansas Territorial Governor James W. Denver. Larimer hoped the name would help make it the county seat of Arapaho County but, unbeknownst to him. The location was accessible to existing trails and was across the South Platte River from the site of seasonal encampments of the Cheyenne, the site of these first towns is now the site of Confluence Park near downtown Denver. Larimer, along with associates in the St. Charles City Land Company, sold parcels in the town to merchants and miners, Denver City was a frontier town, with an economy based on servicing local miners with gambling, saloons, livestock and goods trading. In the early years, land parcels were often traded for grubstakes or gambled away by miners in Auraria, in May 1859, Denver City residents donated 53 lots to the Leavenworth & Pikes Peak Express in order to secure the regions first overland wagon route. Offering daily service for passengers, mail, freight, and gold, in 1863, Western Union furthered Denvers dominance of the region by choosing the city for its regional terminus. The Colorado Territory was created on February 28,1861, Arapahoe County was formed on November 1,1861, Denver City served as the Arapahoe County Seat from 1861 until consolidation in 1902. In 1867, Denver City became the territorial capital, with its newfound importance, Denver City shortened its name to Denver
31.
Colorado
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Colorado is a state in the United States encompassing most of the Southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is part of the Western United States, the Southwestern United States, Colorado is the 8th most extensive and the 21st most populous of the 50 United States. The United States Census Bureau estimates that the population of Colorado was 5,540,545 on July 1,2016, the state was named for the Colorado River, which Spanish travelers named the Río Colorado for the ruddy silt the river carried from the mountains. The Territory of Colorado was organized on February 28,1861, Colorado is nicknamed the Centennial State because it became a state in the same year as the centennial of the United States Declaration of Independence. Colorado is noted for its landscape of mountains, forests, high plains, mesas, canyons, plateaus, rivers. Denver is the capital and the most populous city of Colorado, residents of the state are properly known as Coloradans, although the term Coloradoan has been used archaically and lives on in the title of Fort Collins newspaper, the Coloradoan. Colorado, Wyoming and Utah are the states which have boundaries defined solely by lines of latitude and longitude. The summit of Mount Elbert at 14,440 feet elevation in Lake County is the highest point in Colorado, Colorado is the only U. S. state that lies entirely above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County, Colorado and this point, which holds the distinction of being the highest low elevation point of any state, is higher than the high elevation points of 18 states and the District of Columbia. A little less than one half of the area of Colorado is flat, East of the Rocky Mountains are the Colorado Eastern Plains of the High Plains, the section of the Great Plains within Nebraska at elevations ranging from roughly 3,350 to 7,500 feet. The Colorado plains were mostly prairies, but they have many patches of forests, buttes. Eastern Colorado is presently covered in farmland and rangeland, along with small farming villages. Precipitation is fair, averaging from 15 to 25 inches annually, corn, wheat, hay, soybeans, and oats are all typical crops, and most of the villages and towns in this region boast both a water tower and a grain elevator. Irrigation water is available from the South Platte, the Arkansas River, and a few other streams, however, heavy use of ground water from wells for irrigation has caused underground water reserves to decline. As well as agriculture, eastern Colorado hosts considerable livestock, such as cattle ranches. Roughly 70% of Colorados population resides along the edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne, Wyoming, and Pueblo, Colorado. This region is protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado. The Front Range includes Denver, Boulder, Fort Collins, Loveland, Colorado Springs, Pueblo, Greeley and other townships, on the other side of the Rockies, the significant population centers in Western Colorado are the cities of Grand Junction, Durango, and Montrose
32.
Central Valley (California)
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Californias Central Valley is a large, flat valley that dominates the geographical center of the U. S. state of California. It is 40 to 60 miles wide and stretches approximately 450 miles from north-northwest to south-southeast, inland from and it covers approximately 18,000 square miles, about 11% of Californias total land area. More than 7 million acres of the valley are irrigated via a system of reservoirs. The valley also has many cities, including the state capital Sacramento, as well as Redding, Stockton, Modesto, Fresno. The Central Valley watershed comprises 60,000 square miles, or over a third of California, the delta empties into the San Francisco Bay, and then ultimately flows into the Pacific. The Central Valley is commonly known to simply as the Valley. Older names include the Great Valley, a name often seen in scientific references, and Golden Empire. The Central Valley is outlined by the Cascade, Sierra Nevada, and Tehachapi mountain ranges on the east, the broad valley floor is carpeted by vast agricultural regions, and dotted with numerous population centers. While there are many large and small between these cities, these four cities act as hubs for regional commerce and transportation. About 6.5 million people live in the Central Valley today, there are 12 Metropolitan Statistical Areas and 1 Micropolitan Statistical Area in the Central Valley. Below, they are listed by MSA and μSA population, the largest city is Fresno, followed by the state capital, Sacramento. The valley is thought to have originated below sea level as an offshore area depressed by subduction of the Farallon Plate into a trench further offshore, the San Joaquin Fault is a notable seismic feature of the Central Valley. The valley was later enclosed by the uplift of the Coast Ranges, faulting moved the Coast Ranges, and a new outlet developed near what is now San Francisco Bay. The one notable exception to the valley floor is Sutter Buttes. Another significant geologic feature of the Central Valley lies hidden beneath the delta, the Stockton Arch is an upwarping of the crust beneath the valley sediments which extends southwest to northeast across the valley. However, much of the Central Valley environment has been removed or altered by human activity including the introduction of exotic plants, the oak woodlands and chaparral that fringe the valley have been categorized as the California interior chaparral and woodlands ecoregion. The wetlands have been the target of operations to restore areas nearly destroyed by agriculture. The dominant grass of the valley was Nassella pulchra mixed with other species, grassland flowers include California poppy, lupins, and purple owls clover which can still be seen, especially in Antelope Valley in the Tehachapi hills
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Basin and Range Province
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The Basin and Range Province is a vast physiographic region that covers much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by changes in elevation. The physiography of the province is the result of tectonic extension that began around 17 Mya in Early Miocene time, the numerous ranges within the Province in the United States are collectively referred to as the Great Basin Ranges, although many are not actually in the Great Basin. Major ranges include the Snake Range, the Panamint Range, the White Mountains, the Sandia Mountains, pico de Orizaba is unambiguously part of the Trans-Mexican Volcanic Belt which has little in common with the Basin and Range Province. The highest point fully within the Province is White Mountain Peak in California, the Provinces climate is arid, with numerous ecoregions. Most North American deserts are located in the Province, the Basin and Range Province includes much of western North America. The Basin and Range Province extends north to the Columbia Plateau and south as far as the Trans-Mexican Volcanic Belt in Mexico, though the boundaries of the Basin. In Mexico, the Basin and Range Province is dominated by, common geographic features include numerous endorheic basins, ephemeral lakes, plateaus, and valleys alternating with mountains. The area is arid and sparsely populated, although there are several major metropolitan areas, including Mexico City. It is generally accepted that basin and range topography is the result of extension and thinning of the lithosphere, extensional environments like the Basin and Range are characterized by listric normal faulting, or faults that level out with depth. Opposing normal faults link at depth producing a horst and graben geometry, the average crustal thickness of the Basin and Range Province is approximately 30 –35 km and is comparable to extended continental crust around the world. The crust in conjunction with the mantle comprises the lithosphere. The base of the lithosphere beneath the Basin and Range is estimated to be about 60 –70 km, opinions vary regarding the total extension of the region, however, the median estimate is about 100% total lateral extension. Evidence exists to suggest that extension began in the southern Basin and Range. The tectonic mechanisms responsible for extension in the Basin and Range province are controversial. Most of the pertinent tectonic plate movement associated with the Basin and Range Province occurred in Neogene time, by Early Miocene time, much of the Farallon Plate had been consumed, and the seafloor spreading ridge that separated the Farallon Plate from the Pacific Plate approached North America. The movement at this boundary divided the East Pacific Rise and spawned the San Andreas transform fault, today, the Pacific Plate moves north-westward relative to North America, a configuration which has given rise to increased shearing along the continental margin. The tectonic activity responsible for the extension in the Basin and Range is a complex, the most accepted hypothesis suggests that crustal shearing associated with the San Andreas Fault caused spontaneous extensional faulting similar to that seen in the Great Basin
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Colorado Plateau
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The province covers an area of 337,000 km2 within western Colorado, northwestern New Mexico, southern and eastern Utah, and northern Arizona. About 90% of the area is drained by the Colorado River and its tributaries, the Green, San Juan. Most of the remainder of the plateau is drained by the Rio Grande, the Colorado Plateau is largely made up of high desert, with scattered areas of forests. In the southwest corner of the Colorado Plateau lies the Grand Canyon of the Colorado River, much of the Plateaus landscape is related, in both appearance and geologic history, to the Grand Canyon. The nickname Red Rock Country suggests the brightly colored rock left bare to the view by dryness, domes, hoodoos, fins, reefs, river narrows, natural bridges, and slot canyons are only some of the additional features typical of the Plateau. The Colorado Plateau has the greatest concentration of U. S. National Park Service units in the country outside of the Washington, DC metropolitan area. Among its ten National Parks are Grand Canyon, Glen Canyon, Zion, Bryce Canyon, Capitol Reef, Canyonlands, Arches, Mesa Verde, and Petrified Forest. The province is bounded by the Rocky Mountains in Colorado, and by the Uinta Mountains and Wasatch Mountains branches of the Rockies in northern and it is also bounded by the Rio Grande Rift, Mogollon Rim and the Basin and Range Province. Isolated ranges of the Southern Rocky Mountains such as the San Juan Mountains in Colorado, north-south trending normal faults that include the Hurricane, Sevier, Grand Wash, and Paunsaugunt separate the sections component plateaus. This fault pattern is caused by the forces pulling apart the adjacent Basin and Range province to the west. Occupying the southeast corner of the Colorado Plateau is the Datil Section, thick sequences of mid-Tertiary to late-Cenozoic-aged lava covers this section. Development of the province has in part been influenced by structural features in its oldest rocks. Part of the Wasatch Line and its various faults form the edge of the province. Faults that run parallel to the Wasatch Fault that lies along the Wasatch Range form the boundaries between the plateaus in the High Plateaus Section, the Uinta Basin, Uncompahgre Uplift, and the Paradox Basin were also created by movement along structural weaknesses in the regions oldest rock. Some sources also include the Tushar Mountain Plateau as part of the Colorado Plateau, the mostly flat-lying sedimentary rock units that make up these plateaus are found in component plateaus that are between 1500 m to over 3350 m above sea level. A supersequence of these rocks is exposed in the various cliffs, within these rocks are abundant mineral resources that include uranium, coal, petroleum, and natural gas. Study of the unusually clear geologic history has greatly advanced that science. A rain shadow from the Sierra Nevada far to the west, higher areas receive more precipitation and are covered in forests of pine, fir, and spruce
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Columbia Plateau
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The Columbia Plateau is a geologic and geographic region that lies across parts of the U. S. states of Washington, Oregon, and Idaho. It is a flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River. In one of various usages, the term Columbia Basin refers to more or less the area as the Columbia Plateau. Over a period of perhaps 10 to 15 million years, lava flow after lava flow poured out, as the molten rock came to the surface, the Earths crust gradually sank into the space left by the rising lava. Many of these formations are subdivided into formal and informal members, the subsidence of the crust produced the large plateau—a large, slightly depressed lava plain sometimes also known as the Columbia Basin. The ancient Columbia River was forced into its present course by the advancing lava. The lava, as it flowed over the area, first filled the stream valleys, entities found in these lake beds include fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals. Columbia River Basin Ethnic History Archive
36.
Cascade Range
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The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades, the small part of the range in British Columbia is referred to as the Canadian Cascades or, locally, as the Cascade Mountains. The highest peak in the range is Mount Rainier in Washington at 14,411 feet, the Cascades are part of the Pacific Oceans Ring of Fire, the ring of volcanoes and associated mountains around the Pacific Ocean. All of the eruptions in the contiguous United States over the last 200 years have been from Cascade volcanoes, the two most recent were Lassen Peak from 1914 to 1921 and a major eruption of Mount St. Helens in 1980. Minor eruptions of Mount St. Helens have also occurred since, the Cascade Range is a part of the American Cordillera, a nearly continuous chain of mountain ranges that form the western backbone of North America, Central America, and South America. The Cascades extend northward from Lassen Peak in northern California to the confluence of the Nicola, the Fraser River separates the Cascades from the Coast Mountains. The highest volcanoes of the Cascades, known as the High Cascades, dominate their surroundings and they often have a visual height of one mile or more. The highest peaks, such as the 14, 411-foot Mount Rainier, Mount Baker in Washington recorded a world-record single-season snowfall in the winter of 1998–99 with 1,140 inches. Prior to that year, Mount Rainier held the record for snow accumulation at Paradise in 1978. It is not uncommon for some places in the Cascades to have over 500 inches of snow accumulation, such as at Lake Helen. Most of the High Cascades are therefore white with snow and ice year-round, annual rainfall is as low as 9 inches on the eastern foothills due to a rain shadow effect. Beyond the eastern foothills is a plateau that was largely created 17 to 14 million years ago by the many flows of the Columbia River Basalt Group. Together, these sequences of fluid volcanic rock form the 200, 000-square-mile Columbia Plateau in eastern Washington, Oregon, the Columbia River Gorge is the only major break of the range in the United States. When the Cascades began to rise 7 million years ago in the Pliocene, as the range grew, erosion from the Columbia River was able to keep pace, creating the gorge and major pass seen today. The gorge also exposes uplifted and warped layers of basalt from the plateau, in early 1792, British navigator George Vancouver explored Puget Sound and gave English names to the high mountains he saw. Mount Baker was named for Vancouvers third lieutenant, Joseph Baker, although the first European to see it was Manuel Quimper, Mount Rainier was named after Admiral Peter Rainier. Later in 1792, Vancouver had his lieutenant William Robert Broughton explore the lower Columbia River and he named Mount Hood after Lord Samuel Hood, an admiral of the Royal Navy. Mount St. Helens was sighted by Vancouver in May 1792 and it was named for Alleyne FitzHerbert, 1st Baron St Helens, a British diplomat
37.
Sierra Madre Occidental
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The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through Northwestern and Western Mexico, and along the Gulf of California. The Spanish name sierra madre means mother mountains and occidental means western in English, the range extends from northern Sonora state near the Mexico-U. S. Border at Arizona, southeastwards to the Trans-Mexican Volcanic Belt and Sierra Madre del Sur ranges, the high plateau that is formed by the range is cut by deep river valleys. This plateau is formed from volcanic rock overlying a basement of metamorphic rock and this uplift has caused changes in weather patterns, increased rainfall occurring in the mountains has provided areas where ecosystems can form in wetter areas than surrounding land. This water-source forms watersheds that provide the arid surroundings with water makes it possible to irrigate. The wet ecosystems are islands of biodiversity, differing significantly from what would otherwise be a desert landscape, oak forests are the predominant plant life and extend into the low land deserts. The major industries in the area now are agriculture and forestry, which have become contentious because of land degradation, the range trends from the north to southeast. Canyons cut by the rivers of the wet western slopes exist in addition to those of the northeast slopes, the mountains range from 300 km from the Gulf of California in the north, but begin to approach within 50 km of the Pacific in the south. These mountains are considered to be part of the much larger American cordillera. The Sierra Tarahumara or Tarahumara range is the name for the region of the Sierra Madre beginning at the Durango border and this name comes from the Tarahumara natives. This is a landscape of steep mountains formed by a high plateau that has been cut through with canyons including Copper Canyon, larger and, in places. This plateau has an elevation of 2,250 m with most of the more eroded canyons on the western slope. The highest elevations occur in the Tarahumara range, the exact elevations of the highest peaks are not known within accurate enough ranges to determine the relative elevation of peaks. The highest point is probably Cerro Mohinora, located at 25°57′N 107°03′W, estimates for the height of the mountain start around 3,040 m and go up to 3,300 m. However, Cerro Barajas, at 26°24′N 106°5′W, may be as high as 3,300 m although other sources give 3,170 m as the elevation, Cerro Gordo, at 23°12′N 104°57′W, may have an elevation between 3,350 m and 3,340 m. The southern end of the mountains may be referred to as the Sierra Huichola, in this area the Sierra Madre begin to give way to the basin and range province. Subranges of this include the Sierra de Alica and the Sierra Pajaritos both in Nayarit. The mountains act as a source of water, in an arid environment from the increased precipitation from the mountain range
38.
Sierra Madre Oriental
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The Sierra Madre Oriental is a mountain range in northeastern Mexico. The northernmost are the Sierra del Burro and the Sierra del Carmen which reach the border with the United States at the Rio Grande, north of the Rio Grande, the range continues northwestward into Texas and beyond as the Davis and Guadalupe Ranges. Mexicos Gulf Coastal Plain lies to the east of the range, the Mexican Plateau, which averages 1,100 metres in elevation, lies between the Sierra Madre Oriental and the Sierra Madre Occidental further west. The climate of the Sierra Madre Oriental is drier than the rainforest areas further south. The highest point is Cerro San Rafael, at 3,700 metres above sea level, is the highest point of the Sierra Madre Oriental and the state of Coahuila and the second in Mexico in isolation. This long range of mountains is noted for its abundant biodiversity and large number of endemic species of plants and wildlife. The Sierra Madre Oriental pine-oak forests are found at elevations in the range. Much of the wildlife can also be found in the Sierra Madre Occidental, which runs parallel to these mountains along western Mexico. Pine-oak forests are dominated by species of pine, such as Pinus nelsonii, P. cembroides, P. pseudostrobus, and P. arizonica. Matorral is characterized by woody shrubs, small trees, cacti, montane chaparral is found above 1,700 m and is home to species in the genera Quercus, Arbutus, Yucca, Cercocarpus and Bauhinia. Piedmont scrub occurs below 2,000 m and is composed of plants 3 to 5 m in height such as Helietta parvifolia, birds of the forest include the Mexican chickadee, Montezuma quail, Stricklands woodpecker, zone-tailed hawk and several species of jay. Pine-oak forests in Coahuila are part of the route of monarch butterflies. Original habitats have been reduced by clearance for livestock grazing and logging over hundreds of years. Protected areas include the Cumbres de Monterrey National Park in Mexico, the El Cielo Biosphere in Tamaulipas preserves the northernmost tropical Veracruz moist forests in Mexico and extensive temperate cloud forests. Mountain peaks of Mexico Sierra Madre Oriental pine-oak forests
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Mexican Plateau
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The Central Mexican Plateau, also known as the Mexican Altiplano, is a large arid-to-semiarid plateau that occupies much of northern and central Mexico. A low east-west mountain range in the state of Zacatecas divides the plateau into northern and southern sections and these two sections, called the Northern Plateau and Central Plateau, are now generally regarded by geographers as sections of one plateau. The Mexican Plateau is mostly covered by deserts and xeric shrublands, with forests covering the surrounding mountain ranges. The Mexican Altiplano is one of six distinct sections of the Basin and Range Province. In phytogeography, the Sonoran Desert is within the Sonoran Floristic Province of the Madrean Region in southwestern North America, various narrow, isolated ridges cross the Mesa del Norte and numerous depressions also dot the region, the largest of which is the Bolsón de Mapimí. The Río Bravo del Norte and its tributary, the Río Conchos, drain portions of the plateau. Both drain to the Gulf of Mexico, much of the northern plateau comprises internal drainage basins that do not drain to the sea. The Mesa Central or southern plateau is higher than its northern counterpart, the southern plateau contains numerous valleys originally formed by ancient lakes. It extends across the states of Aguascalientes, Jalisco, Zacatecas, Guanajuato, Querétaro, Michoacán, México, several of Mexicos most prominent cities, including Mexico City and Guadalajara, are located in the valleys of the southern plateau. Much of the plateau is drained by the Río Grande de Santiago and its tributaries, including the Río Lerma. Tributaries of the Río Pánuco drain the eastern portion of the southern plateau, the Central Mexican matorral covers much of the southern plateau, with the subtropical Bajío dry forests occupying the lower portions of the Lerma–Río Grande de Santiago basin. Higher altitudes are covered by Mixed Forests, then Temperate Coniferous Forests and this article incorporates public domain material from the Library of Congress Country Studies website http, //lcweb2. loc. gov/frd/cs/. Ricketts, Taylor H. Eric Dinerstein, David M. Olson, Colby J. Loucks, terrestrial Ecoregions of North America, a Conservation Assessment. Image Science and Analysis Laboratory, NASA-Johnson Space Center, earth from Space - Image Information
40.
Peninsular Ranges
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Elevations range from 500 to 10,834 feet. Sierra San Francisco, Sierra de la Giganta, and Sierra de la Laguna in Baja California, Palomar Mountain, home to Palomar Observatory, is in the Peninsular Ranges in San Diego County, as is Viejas Mountain. The Peninsular ranges run predominantly north-south, unlike the Transverse Ranges to their north, rocks in the ranges are dominated by Mesozoic granitic rocks, derived from the same massive batholith which forms the core of the Sierra Nevada Mountains in California. They are part of a province known as the Salinian Block which broke off the North American Plate as the San Andreas Fault. Between this set of ranges and the Transverse Ranges is the complex Malibu Coast—Santa Monica—Hollywood fault, most of the Peninsular Ranges are in the Nearctic ecozone. Several terrestrial ecoregions cover portions of the Peninsular Ranges, on western-coast side of the southern portion of the ranges the Baja California desert ecoregion covers in the southern portion of the Peninsular Ranges in Baja California and Baja California Sur. On eastern side of northern ranges, the Sonoran Desert ecoregion covers southeastern California and northeastern Baja California as far south as the town of Loreto, Baja California Sur. On the eastern side of the Laguna Mountains in San Diego County the Anza-Borrego Desert State Park is known for its profusion of Colorado Desert wildflowers. On eastern-Gulf of California side of the portion of the ranges the Gulf of California xeric scrub ecoregion covers the range in Baja California Sur. The higher portions of the Peninsular Ranges, especially the slopes, are home to coniferous. Cleveland National Forest covers much of the higher Southern California Peninsular Ranges, the vegetation includes oak woodlands and forests of Jeffrey Pine and Coulter Pine. The Sierra Juarez and San Pedro Martir pine-oak forests cover upper slopes of Sierra Juarez and these isolated forests, predominantly Tamarack Pine, Sugar Pine, Parry Pinyon, White Fir, California Incense Cedar, and junipers. Oak species include Coast Live Oak, Engelmann Oak, Canyon Live Oak and these higher portions of the Peninsular Ranges harbor many rare and endemic species. Southern Baja California Sur is part of the Neotropic ecozone and its flora and fauna share many affinities with southern Mexico and Central America. It includes three distinct ecoregions, the Sierra de la Laguna dry forests, Sierra de la Laguna pine-oak forests, Peninsular Ranges index Transverse Ranges List of mountain ranges
41.
Sierra Madre del Sur
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The Sierra Madre del Sur is a mountain range in southern Mexico, extending 1,000 kilometres from southern Michoacán east through Guerrero, to the Isthmus of Tehuantepec in eastern Oaxaca. The mountains highest point is 3,703 metres, located at 17°33′N 100°18′W in central Guerrero, the range is noted for its very high biodiversity and large number of endemic species. The Sierra Madre del Sur pine-oak forests ecoregion occupies the higher reaches of the range and these forests are part of a chain of Mesoamerican pine-oak forests that stretch from the Southwestern United States to Costa Rica along the American Cordillera. Lower elevations of the range are covered by tropical dry forests, the Jalisco dry forests occupy the western end of the ranges Pacific slope. The Southern Pacific dry forests occupy most of the Pacific slope of the range, from Michoacan in the west through Guerrero, the basin of the Balsas River, north of the Sierra, is home to the Balsas dry forests. Sierra Madre del Sur pine-oak forests, Sierra Madre del Sur pine-oak forests. Archived from the original on 2010-03-08
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British Columbia
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British Columbia is the westernmost province of Canada, with a population of more than four million people located between the Pacific Ocean and the Rocky Mountains. British Columbia is also a component of the Pacific Northwest and the Cascadia bioregion, along with the U. S. states of Idaho, Oregon, Washington and Alaska. The first British settlement in the area was Fort Victoria, established in 1843, subsequently, on the mainland, the Colony of British Columbia was founded by Richard Clement Moody and the Royal Engineers, Columbia Detachment, in response to the Fraser Canyon Gold Rush. Port Moody is named after him, in 1866, Vancouver Island became part of the colony of British Columbia, and Victoria became the united colonys capital. In 1871, British Columbia became the province of Canada. Its Latin motto is Splendor sine occasu, the capital of British Columbia remains Victoria, the fifteenth-largest metropolitan region in Canada, named for the Queen who created the original European colonies. The largest city is Vancouver, the third-largest metropolitan area in Canada, the largest in Western Canada, in October 2013, British Columbia had an estimated population of 4,606,371. British Columbia evolved from British possessions that were established in what is now British Columbia by 1871, First Nations, the original inhabitants of the land, have a history of at least 10,000 years in the area. Today there are few treaties and the question of Aboriginal Title, notably, the Tsilhqotin Nation has established Aboriginal title to a portion of their territory, as a result of the recent Supreme Court of Canada decision. BCs economy is diverse, with service producing industries accounting for the largest portion of the provinces GDP and it is the endpoint of transcontinental railways, and the site of major Pacific ports that enable international trade. Though less than 5% of its vast 944,735 km2 land is arable and its climate encourages outdoor recreation and tourism, though its economic mainstay has long been resource extraction, principally logging, farming, and mining. Vancouver, the provinces largest city and metropolitan area, also serves as the headquarters of many western-based natural resource companies and it also benefits from a strong housing market and a per capita income well above the national average. The Northern Interior region has a climate with very cold winters. The climate of Vancouver is by far the mildest winter climate of the major Canadian cities, the provinces name was chosen by Queen Victoria, when the Colony of British Columbia, i. e. the Mainland, became a British colony in 1858. The current southern border of British Columbia was established by the 1846 Oregon Treaty, British Columbias land area is 944,735 square kilometres. British Columbias rugged coastline stretches for more than 27,000 kilometres and it is the only province in Canada that borders the Pacific Ocean. British Columbias capital is Victoria, located at the tip of Vancouver Island. Only a narrow strip of the Island, from Campbell River to Victoria, is significantly populated, much of the western part of Vancouver Island and the rest of the coast is covered by thick, tall and sometimes impenetrable temperate rainforest
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Fjord
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Geologically, a fjord or fiord is a long, narrow inlet with steep sides or cliffs, created by glacial erosion. Norways coastline is estimated at 29,000 kilometres with 1,190 fjords, a fjord is formed when a glacier cuts a U-shaped valley by ice segregation and abrasion of the surrounding bedrock. Glacial melting is accompanied by the rebounding of Earths crust as the ice load, in some cases this rebound is faster than sea level rise. Most fjords are deeper than the adjacent sea, Sognefjord, Norway, fjords generally have a sill or shoal at their mouth caused by the previous glaciers reduced erosion rate and terminal moraine. In many cases this causes extreme currents and large saltwater rapids. Saltstraumen in Norway is often described as the worlds strongest tidal current and these characteristics distinguish fjords from rias, which are drowned valleys flooded by the rising sea. Drammensfjorden is cut almost in two by the Svelvik ridge, a moraine that during the ice cover was under sea level. During the winter there is usually little inflow of freshwater. Surface water and deeper water are mixed during winter because of the cooling of the surface. In the deep there is still fresh water from the summer with less density than the saltier water along the coast. Offshore wind, common in the areas during winter, sets up a current on the surface from the inner to the outer parts. This current on the surface in turn pulls dense salt water from the coast across the fjord threshold, during the summer season there is usually a large inflow of river water in the inner areas. This freshwater gets mixed with saltwater creating a layer of water with a slightly higher surface than the ocean which in turn sets up a current from the river mouths towards the ocean. This current is more salty towards the coast and right under the surface current there is a reverse current of saltier water from the coast. In the deeper parts of the fjord the cold water remaining from winter is still, fjords with a shallow threshold this deep water is not replaced every year and low oxygen concentration makes the deep water unsuitable for fish and animals. In the most extreme cases there is a constant barrier of freshwater on the surface, gaupnefjorden branch of Sognefjorden is strongly affected by freshwater as glacial river flow in. Velfjorden has little inflow of freshwater, as late as 2000, some coral reefs were discovered along the bottoms of the Norwegian fjords. These reefs were found in fjords from the north of Norway to the south, the marine life on the reefs is believed to be one of the most important reasons why the Norwegian coastline is such a generous fishing ground
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Channel Islands (California)
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The Channel Islands of California are a chain of eight islands located in the Pacific Ocean off the coast of southern California along the Santa Barbara Channel in the United States of America. Five of the islands are part of Channel Islands National Park, the islands were first colonized by the Chumash and Tongva Native Americans 13,000 years ago, who were then displaced by European settlers who used the islands for fishing and agriculture. The U. S. military uses the islands as training grounds, weapons test sites, the Channel Islands and the surrounding waters house a diverse ecosystem with many endemic species and subspecies. Eight islands are split among the jurisdictions of three separate California counties, Santa Barbara County, Ventura County, and Los Angeles County, the islands are divided into two groups, the northern Channel Islands and the southern Channel Islands. The four northern Islands used to be a single known as Santa Rosae. The archipelago extends for 160 miles between San Miguel Island in the north and San Clemente Island in the south, together, the islands’ land area totals 221,331 acres, or about 346 square miles. Five of the islands were made into the Channel Islands National Park in 1980, the Channel Islands National Marine Sanctuary encompasses the waters six nautical miles off Anacapa, Santa Cruz, San Miguel, Santa Rosa, and Santa Barbara islands. Santa Catalina Island is the one of the eight islands with a significant permanent civilian settlement—the resort city of Avalon, California. Natural seepage of oil occurs at places in the Santa Barbara Channel. Tar balls or pieces of tar in small numbers are found in the kelp, Native Americans used naturally occurring tar, bitumen, for a variety of purposes which include roofing, waterproofing, paving and some ceremonial purposes. The Channel Islands at low elevations are virtually frost-free and constitute one of the few areas in the 48 contiguous US states. It snows only rarely, on mountain peaks. Separated from the California mainland throughout recent geological history, the Channel Islands provide the earliest evidence for seafaring in the Americas. It is also the site of the discovery of the earliest paleontological evidence of humans in North America, the northern Channel Islands are now known to have been settled by maritime Paleo Indian peoples at least 13,000 years ago. Archaeological sites on the island provide a unique and invaluable record of human interaction with Channel Island marine, historically, the northern islands were occupied by the island Chumash, while the southern islands were occupied by the Tongva. Author Scott ODell wrote about the peoples living on the island in his novel Island of the Blue Dolphins. Aleut hunters visited the islands to hunt otters in the early 1800s, the Aleuts purportedly clashed with the native Chumash, killing many over trading disputes. Aleut interactions with the natives were also detailed in ODells book, the Chumash and Tongva were removed from the islands in the early 19th century, taken to Spanish missions and pueblos on the adjacent mainland
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Archipelago
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An archipelago, sometimes called an island group or island chain, is a chain, cluster or collection of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi-, in Italian, possibly following a tradition of antiquity, the Archipelago was the proper name for the Aegean Sea and, later, usage shifted to refer to the Aegean Islands. It is now used to refer to any group or, sometimes. Archipelagos may be isolated in large amounts of water or neighbouring a large land mass. For example, Scotland has more than 700 islands surrounding its mainland which form an archipelago, archipelagos are often volcanic, forming along island arcs generated by subduction zones or hotspots, but may also be the result of erosion, deposition, and land elevation. Depending on their origin, islands forming archipelagos can be referred to as oceanic islands, continental fragments. Oceanic islands are mainly of volcanic origin, continental fragments correspond to land masses that have separated from a continental mass due to tectonic displacement. Indonesia, Japan, Taiwan, the Philippines, New Zealand, Maldives, the Bahamas, Greece, Hawaii, the largest archipelagic state in the world by area and population is Indonesia. Island arc List of landforms List of archipelagos by number of islands List of archipelagos List of islands Chisholm, Hugh, ed. Archipelago
Media related to North American Cordillera at Wikimedia Commons
