Misplaced Pages

#742257

118-681: The islands were formed over 2,000 years ago as the rim of the St. Bernard Lobe of the Mississippi River delta. The islands were named when the explorer Pierre Le Moyne d'Iberville was sailing in search of the mouth of the Mississippi River along the Gulf Coast. He christened the islands on the eve of Fête de la Chandeleur —also known as Candlemas, a Christian feast day—on February 1, 1700. The Breton National Wildlife Refuge

236-585: A European was in the journal of Jacques Legardeur de Saint-Pierre in 1752, where they were called " montagnes de Roche ". Another name given to the place by the Cree is ᐊᓭᓂᐓᒉ Aseniwuche . The Rocky Mountains are the easternmost portion of the expansive North American Cordillera . They are often defined as stretching from the Liard River in British Columbia south to the headwaters of

354-461: A decade after this paper was published, the islands remain largely unchanged. Boston dot com article 2006 is a dead link, internet archive data: https://web.archive.org/web/20070704010017/http://www.boston.com/news/science/articles/2006/08/02/chandeleur_islands_said_not_rebuilding/ 29°50′09″N 88°50′04″W  /  29.83583°N 88.83444°W  / 29.83583; -88.83444 Mississippi River The Mississippi River

472-542: A large mound of sand spanning the width of the river 55 feet below the surface, allowing fresh water and large cargo ships to pass over. Fresh river water flowing from the Mississippi into the Gulf of Mexico does not mix into the salt water immediately. The images from NASA 's MODIS show a large plume of fresh water, which appears as a dark ribbon against the lighter-blue surrounding waters. These images demonstrate that

590-666: A length of 3,710 miles (5,971 km), making it the fourth longest river in the world after the Nile , Amazon , and Yangtze . When measured by the largest stream source (by water volume), the Ohio River , by extension the Allegheny River , would be the source, and the Mississippi would begin in Pennsylvania . At its source at Lake Itasca , the Mississippi River is about 3 feet (0.91 m) deep. The average depth of

708-523: A mixture of white pine, fir, and spruce that appear as shrub-like krummholz . Finally, rivers and canyons can create a unique forest zone in more arid parts of the mountain range. The Rocky Mountains are an important habitat for a great deal of well-known wildlife, such as wolves , elk , moose , mule and white-tailed deer , pronghorn , mountain goats , bighorn sheep , badgers , black bears , grizzly bears , coyotes , lynxes , cougars , and wolverines . North America's largest herds of elk are in

826-478: A natural process known as avulsion or delta switching, the lower Mississippi River has shifted its final course to the mouth of the Gulf of Mexico every thousand years or so. This occurs because the deposits of silt and sediment begin to clog its channel, raising the river's level and causing it to eventually find a steeper, more direct route to the Gulf of Mexico. The abandoned distributaries diminish in volume and form what are known as bayous . This process has, over

944-893: A similar relationship to tourism promotions by the Great Northern Railway . While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. U.S. President Benjamin Harrison established several forest reserves in the Rocky Mountains in 1891–1892. In 1905, U.S. President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park . Economic development began to center on mining, forestry , agriculture, and recreation , as well as on

1062-794: Is 208,200 cu ft/s (5,900 m /s). Thus, by volume, the main branch of the Mississippi River system at Cairo can be considered to be the Ohio River (and the Allegheny River further upstream), rather than the Middle Mississippi. In addition to the Ohio River , the major tributaries of the Lower Mississippi River are the White River , flowing in at the White River National Wildlife Refuge in east-central Arkansas;

1180-575: Is a meandering river in a broad, flat area, only rarely flowing alongside a bluff (as at Vicksburg, Mississippi ). The Mississippi River is known as the Middle Mississippi from the Upper Mississippi River's confluence with the Missouri River at St. Louis, Missouri , for 190 miles (310 km) to its confluence with the Ohio River at Cairo, Illinois . The Middle Mississippi is relatively free-flowing. From St. Louis to

1298-498: Is called the Lower Mississippi River from its confluence with the Ohio River to its mouth at the Gulf of Mexico, a distance of about 1,000 miles (1,600 km). At the confluence of the Ohio and the Middle Mississippi, the long-term mean discharge of the Ohio at Cairo, Illinois is 281,500 cubic feet per second (7,970 cubic meters per second), while the long-term mean discharge of the Mississippi at Thebes, Illinois (just upriver from Cairo)

SECTION 10

#1732772517743

1416-912: Is controlled and managed as a series of pools created by 26 locks and dams. The Upper Mississippi River is joined by the Minnesota River at Fort Snelling in the Twin Cities ; the St. Croix River near Prescott, Wisconsin ; the Cannon River near Red Wing, Minnesota ; the Zumbro River at Wabasha, Minnesota ; the Black , La Crosse , and Root rivers in La Crosse, Wisconsin ; the Wisconsin River at Prairie du Chien, Wisconsin ;

1534-794: Is in the Rocky Mountains and designates the line at which waters flow either to the Atlantic or Pacific Oceans. Triple Divide Peak (2,440 m or 8,020 ft) in Glacier National Park is so named because water falling 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 , which has its outlet on

1652-472: Is largely a multi-thread stream with many bars and islands. From its confluence with the St. Croix River downstream to Dubuque, Iowa , the river is entrenched, with high bedrock bluffs lying on either side. The height of these bluffs decreases to the south of Dubuque, though they are still significant through Savanna, Illinois . This topography contrasts strongly with the Lower Mississippi, which

1770-706: Is natural gas that arises from coal, either through bacterial action or through exposure to high temperature. Coalbed methane supplies 7 percent of the natural gas used in the U.S. The largest coalbed methane sources in the Rocky Mountains are in the San Juan Basin in New Mexico and Colorado and the Powder River Basin in Wyoming. These two basins are estimated to contain 38 trillion cubic feet of gas. Coalbed methane can be recovered by dewatering

1888-588: Is the primary river of the largest drainage basin in the United States . From its traditional source of Lake Itasca in northern Minnesota , it flows generally south for 2,340 miles (3,766 km) to the Mississippi River Delta in the Gulf of Mexico . With its many tributaries , the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between

2006-539: Is the only true waterfall on the entire Mississippi River. The water elevation continues to drop steeply as it passes through the gorge carved by the waterfall. After the completion of the St. Anthony Falls Lock and Dam in 1963, the river's head of navigation moved upstream, to the Coon Rapids Dam . However, the Locks were closed in 2015 to control the spread of invasive Asian carp , making Minneapolis once again

2124-668: The 49th parallel north as the international boundary west from Lake of the Woods to the "Stony Mountains"; the UK and the US agreed to what has since been described as "joint occupancy" of lands further west to the Pacific Ocean. Resolution of the territorial and treaty issues, the Oregon dispute , was deferred until a later time. In 1819, Spain ceded their rights north of the 42nd Parallel to

2242-479: The Alberta–British Columbia foothills forests . The status of most species in the Rocky Mountains is unknown, due to incomplete information. European-American settlement of the mountains has adversely impacted native species. Examples of some species that have declined include western toads , greenback cutthroat trout , white sturgeon , white-tailed ptarmigan , trumpeter swan , and bighorn sheep. In

2360-618: The American Civil War , the Mississippi's capture by Union forces marked a turning point towards victory , due to the river's strategic importance to the Confederate war effort. Because of the substantial growth of cities and the larger ships and barges that replaced steamboats, the first decades of the 20th century saw the construction of massive engineering works such as levees , locks and dams , often built in combination. A major focus of this work has been to prevent

2478-547: The Apache , Arapaho , Bannock , Blackfoot , Cheyenne , Coeur d'Alene , Kalispel , Crow Nation , Flathead , Shoshone , Sioux , Ute , Kutenai (Ktunaxa in Canada), Sekani , Dunne-za , and others. Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains. Like the modern tribes that followed them, Paleo-Indians probably migrated to

SECTION 20

#1732772517743

2596-880: The Arkansas River , joining the Mississippi at Arkansas Post ; the Big Black River in Mississippi; and the Yazoo River , meeting the Mississippi at Vicksburg, Mississippi . Deliberate water diversion at the Old River Control Structure in Louisiana allows the Atchafalaya River in Louisiana to be a major distributary of the Mississippi River, with 30% of the combined flow of the Mississippi and Red Rivers flowing to

2714-810: The Beaufort Sea of the Arctic Ocean. Human population is not very dense in the Rockies, with an average of four people per square kilometer and few cities with over 50,000 people. However, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The forty-year statewide increases in population range from 35% in Montana to about 150% in Utah and Colorado. The populations of several mountain towns and communities have doubled in

2832-709: The Bull Lake Glaciation , which began about 150,000 years ago, and the Pinedale Glaciation , which perhaps remained at full glaciation until 15,000–20,000 years ago. All of these geological processes exposed a complex set of rocks at the surface. For example, volcanic rock from the Paleogene and Neogene periods (66 million – 2.6 million years ago) occurs in the San Juan Mountains and in other areas. Millennia of severe erosion in

2950-608: The Canadian Pacific Railway eventually followed the Kicking Horse and Rogers Passes to the Pacific Ocean. Canadian railway officials also convinced Parliament to set aside vast areas of the Canadian Rockies as Jasper , Banff , Yoho , and Waterton Lakes National Parks , laying the foundation for a tourism industry which thrives to this day. Glacier National Park (MT) was established with

3068-902: The Canadian Rockies . The eastern edge of the Rockies rises dramatically above the Interior Plains of central North America, including the Sangre de Cristo Mountains of New Mexico and Colorado , the Front Range of Colorado, the Wind River Range and Big Horn Mountains of Wyoming , the Absaroka - Beartooth ranges and Rocky Mountain Front of Montana and the Clark Range of Alberta . Central ranges of

3186-507: The Climax mine, near Leadville, Colorado , was the largest producer of molybdenum in the world. Molybdenum is used in heat-resistant steel in such things as cars and planes. The Climax mine employed over 3,000 workers. The Coeur d'Alene mine of northern Idaho produces silver, lead, and zinc. Canada's largest coal mines are near Fernie, British Columbia and Sparwood , British Columbia; additional coal mines exist near Hinton, Alberta , and in

3304-769: The Columbia District for Britain. The party crossed the Rockies into the Columbia Valley , a region of the Rocky Mountain Trench near present-day Radium Hot Springs , British Columbia, then traveled south. Despite such efforts, in 1846, Britain ceded all claim to Columbia District lands south of the 49th parallel to the United States; as resolution to the Oregon boundary dispute by the Oregon Treaty . Thousands passed through

3422-527: The Gulf of Mexico , part of the Atlantic Ocean. The total catchment of the Mississippi River covers nearly 40% of the landmass of the continental United States. The highest point within the watershed is also the highest point of the Rocky Mountains , Mount Elbert at 14,440 feet (4,400 m). In the United States, the Mississippi River drains the majority of the area between the crest of

3540-455: The Gulf of Mexico . The islands were constantly eroded and changed by wave action , and most dramatically after the storm surges following hurricanes . The islands have been generally shrinking and migrating landward since the late 19th century. A survey in the 1980s estimated that they would be in existence for about three more centuries. Before 1996, the seaward front of the islands lost about 20–30 feet of land each year, mostly replaced at

3658-513: The Lewis and Clark Expedition , natural resources such as minerals and fur drove the initial economic exploitation of the mountains, although the range itself never experienced a dense population. Most of the highest summits of the Rocky Mountains are in Colorado , with that state having an average elevation in excess of 2,000 metres (6,600 ft). Public parks and forest lands protect much of

Chandeleur Islands - Misplaced Pages Continue

3776-676: The Liard River and east of the Rocky Mountain Trench , and do not extend into Yukon , Northwest Territories or central British Columbia . They are divided into three main groups: the Muskwa Ranges , Hart Ranges (collectively called the Northern Rockies ) and Continental Ranges . Other more northerly mountain ranges of the eastern Canadian Cordillera continue beyond the Liard River valley, including

3894-410: The Minnesota River , James River , and Milk River valleys. When the ice sheet completely retreated, many of these "temporary" rivers found paths to Hudson Bay or the Arctic Ocean, leaving the Mississippi Basin with many features "over-sized" for the existing rivers to have carved in the same time period. Ice sheets during the Illinoian Stage , about 300,000 to 132,000 years before present, blocked

4012-452: The North American plate . The angle of subduction was shallow, resulting in a broad belt of mountains running down western North America. Since then, further tectonic activity and erosion by glaciers have sculpted the Rockies into dramatic peaks and valleys. At the end of the last ice age , humans began inhabiting the mountain range. After explorations of the range by Europeans, such as Sir Alexander Mackenzie , and Anglo-Americans, such as

4130-457: The Ohio and Missouri , formed pathways for the western expansion of the United States. The river also became the subject of American literature , particularly in the writings of Mark Twain . Formed from thick layers of the river's silt deposits, the Mississippi embayment is one of the most fertile regions of the United States; steamboats were widely used in the 19th and early 20th centuries to ship agricultural and industrial goods. During

4248-447: The Paleozoic , western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite . In the southern Rockies, near present-day Colorado, these ancestral rocks were disturbed by mountain building approximately 300 Ma , during the Pennsylvanian . This mountain-building produced the Ancestral Rocky Mountains. They consisted largely of Precambrian metamorphic rock forced upward through layers of

4366-405: The Pecos River , a tributary of the Rio Grande , in New Mexico. The Rockies vary in width from 110 to 480 kilometres (70 to 300 miles). The Rocky Mountains contain the highest peaks in central North America. The range's highest peak is Mount Elbert in Colorado at 4,401 metres (14,440 feet) above sea level. Mount Robson in British Columbia, at 3,954 m (12,972 ft), is the highest peak in

4484-410: The Rio Grande rift and north of the Sandia–Manzano Mountain Range . Being the easternmost portion of the North American Cordillera , the Rockies are distinct from the tectonically younger Cascade Range and Sierra Nevada , which both lie farther to its west. The Rockies formed 55 million to 80 million years ago during the Laramide orogeny , in which a number of plates began sliding underneath

4602-415: The Rock River at the Quad Cities ; the Iowa River near Wapello, Iowa ; the Skunk River south of Burlington, Iowa ; and the Des Moines River at Keokuk, Iowa . Other major tributaries of the Upper Mississippi include the Crow River in Minnesota, the Chippewa River in Wisconsin, the Maquoketa River and the Wapsipinicon River in Iowa, and the Illinois River in Illinois. The Upper Mississippi

4720-435: The Rocky and Appalachian mountains. The river either borders or passes through the states of Minnesota , Wisconsin , Iowa , Illinois , Missouri , Kentucky , Tennessee , Arkansas , Mississippi , and Louisiana . The main stem is entirely within the United States; the total drainage basin is 1,151,000 sq mi (2,980,000 km ), of which only about one percent is in Canada. The Mississippi ranks as

4838-403: The Rocky Mountains and the crest of the Appalachian Mountains , except for various regions drained to Hudson Bay by the Red River of the North ; to the Atlantic Ocean by the Great Lakes and the Saint Lawrence River ; and to the Gulf of Mexico by the Rio Grande , the Alabama and Tombigbee rivers, the Chattahoochee and Appalachicola rivers, and various smaller coastal waterways along

Chandeleur Islands - Misplaced Pages Continue

4956-510: The Sawtooths in central Idaho. The Great Basin and Columbia River Plateau separate these subranges from distinct ranges further to the west. In Canada, the western edge of the Rockies is formed by the huge Rocky Mountain Trench , which runs the length of British Columbia from its beginning as the Kechika Valley on the south bank of the Liard River , to the middle Lake Koocanusa valley in northwestern Montana. The Canadian Rockies are defined by Canadian geographers as everything south of

5074-404: The Selwyn , Mackenzie and Richardson Mountains in Yukon as well as the British Mountains / Brooks Range in Alaska , but those are not officially recognized as part of the Rockies by the Geological Survey of Canada , although the Geological Society of America definition does consider them parts of the Rocky Mountains system as the "Arctic Rockies". The Continental Divide of the Americas

5192-430: The Wyoming Basin transformed intermountain basins into a relatively flat terrain. The Tetons and other north-central ranges contain folded and faulted rocks of Paleozoic and Mesozoic age draped above cores of Proterozoic and Archean igneous and metamorphic rocks ranging in age from 1.2 billion (e.g., Tetons) to more than 3.3 billion years ( Beartooth Mountains ). There are a wide range of environmental factors in

5310-429: The headwaters region and serve multiple purposes, including power generation and recreation. The remaining 29 dams, beginning in downtown Minneapolis, all contain locks and were constructed to improve commercial navigation of the upper river. Taken as a whole, these 43 dams significantly shape the geography and influence the ecology of the upper river. Beginning just below Saint Paul, Minnesota , and continuing throughout

5428-422: The most recent Ice Age . The southernmost extent of this enormous glaciation extended well into the present-day United States and Mississippi basin. When the ice sheet began to recede, hundreds of feet of rich sediment were deposited, creating the flat and fertile landscape of the Mississippi Valley. During the melt, giant glacial rivers found drainage paths into the Mississippi watershed, creating such features as

5546-535: The "Rockies", becoming the first Europeans to report on this uncharted mountain range. Sir Alexander Mackenzie (1764 – March 11, 1820) became the first European to cross the Rocky Mountains in 1793. He found the upper reaches of the Fraser River and reached the Pacific coast of what is now Canada on July 20 of that year, completing the first recorded transcontinental crossing of North America north of Mexico. He arrived at Bella Coola, British Columbia , where he first reached saltwater at South Bentinck Arm, an inlet of

5664-467: The Ancestral Rocky Mountains. Such sedimentary remnants were often tilted at steep angles along the flanks of the modern range; they are now visible in many places throughout the Rockies, and are shown along the Dakota Hogback , an early Cretaceous sandstone formation running along the eastern flank of the modern Rockies. Just after the Laramide orogeny, the Rockies were like Tibet : a high plateau, probably 6,000 metres (20,000 ft) above sea level. In

5782-427: The California and Alaska gold rushes combined and was important in the financing of the Union Army during the American Civil War . The transcontinental railroad was completed in 1869, and Yellowstone National Park was established as the world's first national park in 1872. Meanwhile, a transcontinental railroad in Canada was originally promised in 1871. Though political complications pushed its completion to 1885,

5900-404: The Chandeleur Island Light. Powerful storms can produce changes that would otherwise have taken many years. A study released in 2006 by geologists from the University of New Orleans shows that the usual sand and sediment patterns that rebuilt the islands after big storms have not been restored since Katrina reworked the area. There is also evidence of unprecedented landslides on the seafloor on

6018-402: The Earth's mantle (specifically, the Bermuda hotspot ) that was undergoing a period of intense activity. The upwelling of magma from the hotspot forced the further uplift to a height of perhaps 2–3 km of part of the Appalachian-Ouachita range, forming an arch that blocked southbound water flows. The uplifted land quickly eroded and, as North America moved away from the hot spot and as

SECTION 50

#1732772517743

6136-400: The French rendering of the Anishinaabe ( Ojibwe or Algonquin ) name for the river, Misi-ziibi (Great River). In the 18th century, the river was set by the Treaty of Paris as, for the most part, the western border of the new United States. With the Louisiana Purchase and the country's westward expansion, it became a convenient boundary line between the western and eastern halves of

6254-588: The Gulf of Mexico by this route, rather than continuing down the Mississippi's current channel past Baton Rouge and New Orleans on a longer route to the Gulf. Although the Red River was once an additional tributary, its water now flows separately into the Gulf of Mexico through the Atchafalaya River. The Mississippi River has the world's fourth-largest drainage basin ("watershed" or "catchment"). The basin covers more than 1,245,000 square miles (3,220,000 km ), including all or parts of 32 U.S. states and two Canadian provinces. The drainage basin empties into

6372-409: The Gulf. The Mississippi River empties into the Gulf of Mexico about 100 miles (160 km) downstream from New Orleans. Measurements of the length of the Mississippi from Lake Itasca to the Gulf of Mexico vary somewhat, but the United States Geological Survey 's number is 2,340 miles (3,766 km). The retention time from Lake Itasca to the Gulf is typically about 90 days; while speed varies along

6490-404: The Illinoian Stage. Timeline of outflow course changes In March 1876, the Mississippi suddenly changed course near the settlement of Reverie, Tennessee , leaving a small part of Tipton County, Tennessee , attached to Arkansas and separated from the rest of Tennessee by the new river channel. Since this event was an avulsion , rather than the effect of incremental erosion and deposition,

6608-408: The Midwestern and eastern U.S. These earthquakes created Reelfoot Lake in Tennessee from the altered landscape near the river. When measured from its traditional source at Lake Itasca , the Mississippi has a length of 2,340 miles (3,766 km). When measured from its longest stream source (most distant source from the sea), Brower's Spring in Montana , the source of the Missouri River , it has

6726-416: The Mississippi River between Saint Paul and Saint Louis is between 9 and 12 feet (2.7–3.7 m) deep, the deepest part being Lake Pepin , which averages 20–32 feet (6–10 m) deep and has a maximum depth of 60 feet (18 m). Between where the Missouri River joins the Mississippi at Saint Louis, Missouri, and Cairo, Illinois, the depth averages 30 feet (9 m). Below Cairo, where the Ohio River joins,

6844-411: The Mississippi River has experienced numerous large and small changes to its main course, as well as additions, deletions, and other changes among its numerous tributaries, and the lower Mississippi River has used different pathways as its main channel to the Gulf of Mexico across the delta region. As Pangaea began to break up about 95 million years ago, North America passed over a volcanic " hotspot " in

6962-415: The Mississippi River near New Madrid, Missouri , between Memphis and St. Louis, is related to an aulacogen (failed rift) that formed at the same time as the Gulf of Mexico. This area is still quite active seismically. Four great earthquakes in 1811 and 1812 , estimated at 8 on the Richter magnitude scale , had tremendous local effects in the then sparsely settled area, and were felt in many other places in

7080-430: The Mississippi River. Rocky Mountains The Rocky Mountains , also known as the Rockies , are a major mountain range and the largest mountain system in North America . The Rocky Mountains stretch 3,000 miles (4,800 kilometers) in straight-line distance from the northernmost part of Western Canada , to New Mexico in the Southwestern United States . Depending on differing definitions between Canada and

7198-404: The Mississippi near Rock Island, Illinois, diverting it to its present channel farther to the west, the current western border of Illinois. The Hennepin Canal roughly follows the ancient channel of the Mississippi downstream from Rock Island to Hennepin, Illinois . South of Hennepin, to Alton, Illinois , the current Illinois River follows the ancient channel used by the Mississippi River before

SECTION 60

#1732772517743

7316-529: The Missouri River; the Middle Mississippi, which is downriver from the Missouri to the Ohio River; and the Lower Mississippi , which flows from the Ohio to the Gulf of Mexico. The Upper Mississippi runs from its headwaters to its confluence with the Missouri River at St. Louis, Missouri. It is divided into two sections: The source of the Upper Mississippi branch is traditionally accepted as Lake Itasca , 1,475 feet (450 m) above sea level in Itasca State Park in Clearwater County, Minnesota . The name Itasca

7434-430: The Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture. In 1739, French fur traders Pierre and Paul Mallet, while journeying through the Great Plains, discovered a range of mountains at the headwaters of the Platte River , which local American Indian tribes called

7552-529: The Northern Rockies surrounding Tumbler Ridge, British Columbia . Abandoned mines with their wakes of mine tailings and toxic wastes dot the Rocky Mountain landscape. In one major example, eighty years of zinc mining profoundly polluted the river and bank near Eagle River in north-central Colorado. High concentrations of the metal carried by spring runoff harmed algae , moss , and trout populations. An economic analysis of mining effects at this site revealed declining property values, degraded water quality, and

7670-443: The Ohio River confluence, the Middle Mississippi falls 220 feet (67 m) over 180 miles (290 km) for an average rate of 1.2 feet per mile (23 cm/km). At its confluence with the Ohio River, the Middle Mississippi is 315 feet (96 m) above sea level. Apart from the Missouri and Meramec rivers of Missouri and the Kaskaskia River of Illinois, no major tributaries enter the Middle Mississippi River. The Mississippi River

7788-492: The Pacific Ocean. The Lewis and Clark Expedition (1804–1806) was the first scientific reconnaissance of the Rocky Mountains. Specimens were collected for contemporary botanists, zoologists, and geologists. The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels. Mountain men , primarily French, Spanish, and British, roamed

7906-454: The Plains and the Alpine tundra . The Great Plains lie to the east of the Rockies and is characterized by prairie grasses (below roughly 550 m or 1,800 ft). Alpine tundra occurs in regions above the tree-line for the Rocky Mountains, which varies from 3,700 m (12,000 ft) in New Mexico to 760 m (2,500 ft) at the northern end of the Rockies (near the Yukon). The U.S. Geological Survey defines ten forested zones in

8024-423: The Rockies include the La Sal Range along the Utah -Colorado border, the Abajo Mountains and Henry Mountains of Southeastern Utah, the Uinta Range of Utah and Wyoming, and the Teton Range of Wyoming and Idaho. The western edge of the Rockies includes ranges such as the Wasatch near Salt Lake City , the San Juan Mountains of New Mexico and Colorado, the Bitterroots along the Idaho-Montana border, and

8142-464: The Rockies. Zones in more southern, warmer, or drier areas are defined by the presence of pinyon pines / junipers , ponderosa pines , or oaks mixed with pines . In more northern, colder, or wetter areas, zones are defined by Douglas firs , Cascadian species (such as western hemlock ), lodgepole pines / quaking aspens , or firs mixed with spruce . Near tree-line, zones can consist of white pines (such as whitebark pine or bristlecone pine ); or

8260-410: The Rocky Mountains from 1720 to 1800 seeking mineral deposits and furs. The fur-trading North West Company established Rocky Mountain House as a trading post in what is now the Rocky Mountain Foothills of present-day Alberta in 1799, and their business rivals the Hudson's Bay Company established Acton House nearby. These posts served as bases for most European activity in the Canadian Rockies in

8378-485: The Rocky Mountains is one of more rapid change. The Spanish explorer Francisco Vázquez de Coronado —with a group of soldiers and missionaries marched into the Rocky Mountain region from the south in 1540. In 1610, the Spanish founded the city of Santa Fe , the oldest continuous seat of government in the United States, at the foot of the Rockies in present-day New Mexico. The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed

8496-622: The Rocky Mountains on the Oregon Trail beginning in the 1840s. The Mormons began settling near the Great Salt Lake in 1847. From 1859 to 1864, gold was discovered in Colorado, Idaho, Montana, and British Columbia, sparking several gold rushes bringing thousands of prospectors and miners to explore every mountain and canyon and to create the Rocky Mountains' first major industry. The Idaho gold rush alone produced more gold than

8614-562: The Rocky Mountains. The Rockies range in latitude between the Liard River in British Columbia (at 59° N) and the Rio Grande in New Mexico (at 35° N). Prairie occurs at or below 550 metres (1,800 ft), while the highest peak in the range is Mount Elbert at 4,400 metres (14,440 ft). Precipitation ranges from 250 millimetres (10 in) per year in the southern valleys to 1,500 millimetres (60 in) per year locally in

8732-404: The U.S. portion of the mountain range, apex predators such as grizzly bears and wolf packs had been extirpated from their original ranges, but have partially recovered due to conservation measures and reintroduction . Other recovering species include the bald eagle and the peregrine falcon . Since the last great ice age, the Rocky Mountains were home first to indigenous peoples including

8850-763: The U.S., its northern terminus is located either in northern British Columbia 's Terminal Range south of the Liard River and east of the Trench , or in the northeastern foothills of the Brooks Range / British Mountains that face the Beaufort Sea coasts between the Canning River and the Firth River across the Alaska - Yukon border. Its southernmost point is near the Albuquerque area adjacent to

8968-743: The United Kingdom and the United States over the next few decades failed to settle upon a compromise boundary and the Oregon Dispute became important in geopolitical diplomacy between the British Empire and the new American Republic. In 1841, James Sinclair , Chief Factor of the Hudson's Bay Company, guided some 200 settlers from the Red River Colony west to bolster settlement around Fort Vancouver in an attempt to retain

9086-560: The United States, though these rights did not include possession and also included obligations to Britain and Russia concerning their claims in the same region. After 1802, fur traders and explorers ushered in the first widespread American presence in the Rockies south of the 49th parallel. The more famous of these include William Henry Ashley , Jim Bridger , Kit Carson , John Colter , Thomas Fitzpatrick , Andrew Henry , and Jedediah Smith . On July 24, 1832, Benjamin Bonneville led

9204-546: The Upper Mississippi River is the Upper St. Anthony Falls Lock and Dam in Minneapolis. Above the dam, the river's elevation is 799 feet (244 m). Below the dam, the river's elevation is 750 feet (230 m). This 49-foot (15 m) drop is the largest of all the Mississippi River locks and dams. The origin of the dramatic drop is a waterfall preserved adjacent to the lock under an apron of concrete. Saint Anthony Falls

9322-739: The Upper Mississippi is a simple steel culvert, through which the river (locally named "Nicolet Creek") flows north from Lake Nicolet under "Wilderness Road" to the West Arm of Lake Itasca, within Itasca State Park . The earliest bridge across the Mississippi River was built in 1855. It spanned the river in Minneapolis where the current Hennepin Avenue Bridge is located. No highway or railroad tunnels cross under

9440-555: The areas drained by them. Denser salt water from the Gulf of Mexico forms a salt wedge along the river bottom near the mouth of the river, while fresh water flows near the surface. In drought years, with less fresh water to push it out, salt water can travel many miles upstream—64 miles (103 km) in 2022—contaminating drinking water supplies and requiring the use of desalination . The United States Army Corps of Engineers constructed "saltwater sills" or "underwater levees" to contain this in 1988, 1999, 2012, and 2022. This consists of

9558-428: The coal bed, and separating the gas from the water; or injecting water to fracture the coal to release the gas (so-called hydraulic fracturing ). Agriculture and forestry are major industries. Agriculture includes dryland and irrigated farming and livestock grazing. Livestock are frequently moved between high-elevation summer pastures and low-elevation winter pastures, a practice known as transhumance . Every year

9676-604: The country. This is reflected in the Gateway Arch in St. Louis, which was designed to symbolize the opening of the West, and the focus on the " Trans-Mississippi " region in the Trans-Mississippi Exposition . Regional landmarks are often classified in relation to the river, such as "the highest peak east of the Mississippi " or "the oldest city west of the Mississippi". The FCC also uses it as

9794-427: The course of the river, this gives an overall average of around 26 mi (42 km) per day, or 1 mi (1.6 km) per hour. The stream gradient of the entire river is 0.01%, a drop of 450 m over 3,766 km. The Mississippi River discharges at an annual average rate of between 200 and 700 thousand cubic feet per second (6,000 and 20,000 m /s). The Mississippi is the fourteenth largest river in

9912-466: The delta of the Chippewa River of Wisconsin as it enters the Upper Mississippi, is more than 2 miles (3.2 km) wide. By the time the Upper Mississippi reaches Saint Paul , Minnesota, below Lock and Dam No. 1, it has dropped more than half its original elevation and is 687 feet (209 m) above sea level. From St. Paul to St. Louis, Missouri, the river elevation falls much more slowly and

10030-592: The depth averages 50–100 feet (15–30 m) deep. The deepest part of the river is in New Orleans, where it reaches 200 feet (61 m) deep. The Mississippi River runs through or along 10 states, from Minnesota to Louisiana , and is used to define portions of these states' borders, with Wisconsin , Illinois , Kentucky , Tennessee , and Mississippi along the east side of the river, and Iowa , Missouri , and Arkansas along its west side. Substantial parts of both Minnesota and Louisiana are on either side of

10148-472: The dividing line for broadcast call-signs , which begin with W to the east and K to the west, overlapping in media markets along the river. Due to its size and importance, it has been nicknamed The Mighty Mississippi River or simply The Mighty Mississippi . The Mississippi River can be divided into three sections: the Upper Mississippi , the river from its headwaters to the confluence with

10266-722: The early 19th century. Among the most notable are the expeditions of David Thompson , who followed the Columbia River to the Pacific Ocean. On his 1811 expedition, he camped at the junction of the Columbia River and the Snake River and erected a pole and notice claiming the area for the United Kingdom and stating the intention of the North West Company to build a fort at the site. By the Anglo-American Convention of 1818 , which established

10384-544: The edge of the North American Plate boundary, far to the west of the Rocky Mountain region. It was not until 80 Ma that these effects began reaching the Rockies. The current Rocky Mountains arose in the Laramide orogeny from between 80 and 55 Ma. For the Canadian Rockies, the mountain building is analogous to pushing a rug on a hardwood floor: the rug bunches up and forms wrinkles (mountains). In Canada,

10502-577: The first wagon train across the Rocky Mountains by using South Pass in the present State of Wyoming. Similarly, in the wake of Mackenzie's 1793 expedition, fur trading posts were established west of the Northern Rockies in a region of the northern Interior Plateau of British Columbia which came to be known as New Caledonia , beginning with Fort McLeod (today's community of McLeod Lake) and Fort Fraser , but ultimately focused on Stuart Lake Post (today's Fort St. James ). Negotiations between

10620-481: The forty years 1972–2012. Jackson, Wyoming , increased 260%, from 1,244 to 4,472 residents, in those forty years. 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

10738-503: The hotspot's activity declined, the crust beneath the embayment region cooled, contracted and subsided to a depth of 2.6 km, and around 80 million years ago the Reelfoot Rift formed a trough that was flooded by the Gulf of Mexico . As sea levels dropped, the Mississippi and other rivers extended their courses into the embayment , which gradually became filled with sediment with the Mississippi River at its center. Through

10856-599: The last sixty million years, erosion stripped away the high rocks, revealing the ancestral rocks beneath, and forming the current landscape of the Rockies. Periods of glaciation occurred from the Pleistocene Epoch (1.8 million – 70,000 years ago) to the Holocene Epoch (fewer than 11,000 years ago). These ice ages left their mark on the Rockies, forming extensive glacial landforms, such as U-shaped valleys and cirques . Recent glacial episodes included

10974-402: The last two decades, this number was only 160 million short tons (145 million metric tons) per year. The reduction in sediment transported down the Mississippi River is the result of engineering modification of the Mississippi, Missouri, and Ohio rivers and their tributaries by dams, meander cutoffs , river-training structures, and bank revetments and soil erosion control programs in

11092-520: The limestone laid down in the shallow sea. The mountains eroded throughout the late Paleozoic and early Mesozoic , leaving extensive deposits of sedimentary rock . Terranes began colliding with the western edge of North America in the Mississippian (approximately 350 million years ago), causing the Antler orogeny . For 270 million years, the focus of the effects of plate collisions were near

11210-535: The loss of recreational opportunities. The analysis also revealed that cleanup of the river could yield $ 2.3 million in additional revenue from recreation. In 1983, the former owner of the zinc mine was sued by the Colorado Attorney General for the $ 4.8 million cleanup costs; five years later, ecological recovery was considerable. The Rocky Mountains contain several sedimentary basins that are rich in coalbed methane . Coalbed methane

11328-558: The lower 10 miles (16 km) of the Kaskaskia River, forming a new Mississippi channel and cutting off the town from the rest of the state. Later flooding destroyed most of the remaining town, including the original State House. Today, the remaining 2,300 acres (930 ha) island and community of 14 residents is known as an enclave of Illinois and is accessible only from the Missouri side. The New Madrid Seismic Zone , along

11446-415: The lower Mississippi from shifting into the channel of the Atchafalaya River and bypassing New Orleans . Since the 20th century, the Mississippi River has also experienced major pollution and environmental problems — most notably elevated nutrient and chemical levels from agricultural runoff, the primary contributor to the Gulf of Mexico dead zone . The word Mississippi itself comes from Misi zipi ,

11564-425: The mountain range, and they are popular tourist destinations, especially for hiking, camping, mountaineering, fishing, hunting, mountain biking, snowmobiling, skiing, and snowboarding. The name of the mountains is a calque of an Algonquian name, specifically Plains Cree ᐊᓯᓃᐘᒋᐩ asinîwaciy (originally transcribed as-sin-wati ), literally "rocky mountain / alp". The first mention of their present name by

11682-440: The native way of life as first explorers, then settlers, ventured into the basin in increasing numbers. The river served sometimes as a barrier, forming borders for New Spain , New France , and the early United States, and throughout as a vital transportation artery and communications link. In the 19th century, during the height of the ideology of manifest destiny , the Mississippi and several tributaries, most notably its largest,

11800-449: The new river channel, contiguous with the adjacent state. Also, due to a meander in the river, a small part of western Kentucky is contiguous with Tennessee but isolated from the rest of its state. Many of the communities along the Mississippi River are listed below; most have either historic significance or cultural lore connecting them to the river. They are sequenced from the source of the river to its end. The road crossing highest on

11918-450: The normal 300 to 500 kilometres (200 to 300 mi). Scientists hypothesize that the shallow angle of the subducting plate increased the friction and other interactions with the thick continental mass above it. Tremendous thrusts piled sheets of crust on top of each other, building the broad, high Rocky Mountain range. The current southern Rockies were forced upwards through the layers of Pennsylvanian and Permian sedimentary remnants of

12036-654: The northern peaks. Average January temperatures can range from −7 °C (20 °F) in Prince George, British Columbia, to 6 °C (43 °F) in Trinidad, Colorado . Therefore, there is no single monolithic ecosystem for the entire Rocky Mountain Range. Instead, ecologists divide the Rockies into a number of biotic zones . Each zone is defined by whether it can support trees and the presence of one or more indicator species . Two zones that do not support trees are

12154-620: The past 5,000 years, caused the coastline of south Louisiana to advance toward the Gulf from 15 to 50 miles (24 to 80 km). The currently active delta lobe is called the Birdfoot Delta, after its shape, or the Balize Delta , after La Balize, Louisiana , the first French settlement at the mouth of the Mississippi. The current form of the Mississippi River basin was largely shaped by the Laurentide Ice Sheet of

12272-547: The plains in fall and winter for bison and to the mountains in spring and summer for fish, deer, elk, roots, and berries. In Colorado, along with the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400–5,800 years. A growing body of scientific evidence indicates that indigenous people had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning. Recent human history of

12390-549: The plume did not mix with the surrounding sea water immediately. Instead, it stayed intact as it flowed through the Gulf of Mexico, into the Straits of Florida , and entered the Gulf Stream . The Mississippi River water rounded the tip of Florida and traveled up the southeast coast to the latitude of Georgia before finally mixing in so thoroughly with the ocean that it could no longer be detected by MODIS. Over geologic time,

12508-444: The rear. From 1996 to 2004, the loss rate grew to about 300 feet (91 m) per year. In 1998, Hurricane Georges destroyed the islands and left the lighthouse in the middle of the ocean, and the barrier islands only just recovered when Hurricane Katrina struck on August 29, 2005. However, the combined effect of Hurricane Dennis and Hurricane Katrina in 2005 reduced the island to shoals or sub-surface formations, and toppled

12626-479: The river, although the Mississippi defines part of the boundary of each of these states. In all of these cases, the middle of the riverbed at the time the borders were established was used as the line to define the borders between adjacent states. In various areas, the river has since shifted, but the state borders have not changed, still following the former bed of the Mississippi River as of their establishment, leaving several small isolated areas of one state across

12744-695: The scenic areas of the Rocky Mountains draw millions of tourists. The main language of the Rocky Mountains is English. But there are also linguistic pockets of Spanish and indigenous languages. People from all over the world visit the sites to hike, camp, or engage in mountain sports . In the summer season, examples of tourist attractions are: In the United States: In Canada, the mountain range contains these national parks : Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other and are collectively known as Waterton-Glacier International Peace Park . In

12862-494: The service industries that support them. Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities. Economic resources of the Rocky Mountains are varied and abundant. Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum , silver, tungsten , and zinc . The Wyoming Basin and several smaller areas contain significant reserves of coal, natural gas, oil shale , and petroleum. For example,

12980-400: The side toward the Gulf of Mexico, potentially allowing stronger waves with greater erosional impact to reach the islands. In 2014, numerical models developed by other marine geologists indicated the islands could be mostly submerged within decades due to sea level rise , isolation from Mississippi River delta sediment, mud foundations, sediment transport issues, and damaging storms. However,

13098-400: The site of the head of navigation of the river. The Upper Mississippi has a number of natural and artificial lakes, with its widest point being Lake Winnibigoshish , near Grand Rapids, Minnesota , over 11 miles (18 km) across. Lake Onalaska , created by Lock and Dam No. 7 , near La Crosse, Wisconsin , is more than 4 miles (6.4 km) wide. Lake Pepin , a natural lake formed behind

13216-532: The state line still follows the old channel. The town of Kaskaskia, Illinois once stood on a peninsula at the confluence of the Mississippi and Kaskaskia (Okaw) Rivers . Founded as a French colonial community, it later became the capital of the Illinois Territory and was the first state capital of Illinois until 1819. Beginning in 1844, successive flooding caused the Mississippi River to slowly encroach east. A major flood in 1881 caused it to overtake

13334-655: The terranes and subduction are the foot pushing the rug, the ancestral rocks are the rug, and the Canadian Shield in the middle of the continent is the hardwood floor. Further south, an unusual subduction may have caused the growth of the Rocky Mountains in the United States, where the Farallon Plate dove at a shallow angle below the North American Plate . This low angle moved the focus of melting and mountain building much farther inland than

13452-573: The upper and lower river, the Mississippi is further controlled by thousands of wing dikes that moderate the river's flow in order to maintain an open navigation channel and prevent the river from eroding its banks. The head of navigation on the Mississippi is the St. Anthony Falls Lock. Before the Coon Rapids Dam in Coon Rapids, Minnesota , was built in 1913, steamboats could occasionally go upstream as far as Saint Cloud, Minnesota , depending on river conditions. The uppermost lock and dam on

13570-479: The world by volume. On average, the Mississippi has 8% the flow of the Amazon River , which moves nearly 7 million cubic feet per second (200,000 m /s) during wet seasons. Before 1900, the Mississippi River transported an estimated 440 million short tons (400 million metric tons) of sediment per year from the interior of the United States to coastal Louisiana and the Gulf of Mexico. During

13688-527: The world's tenth-largest river by discharge flow, and the largest in North America. Native Americans have lived along the Mississippi River and its tributaries for thousands of years. Many were hunter-gatherers , but some, such as the Mound Builders , formed prolific agricultural and urban civilizations, and some practiced aquaculture . The arrival of Europeans in the 16th century changed

13806-500: Was chosen to designate the "true head" of the Mississippi River as a combination of the last four letters of the Latin word for truth ( ver itas ) and the first two letters of the Latin word for head ( ca put ). However, the lake is in turn fed by a number of smaller streams. From its origin at Lake Itasca to St. Louis, Missouri , the waterway's flow is moderated by 43 dams. Fourteen of these dams are located above Minneapolis in

13924-602: Was established in 1904 and includes all of the Chandeleur Islands in the Gulf of Mexico. The refuge is the second-oldest in the National Wildlife Refuge System. Prior to destruction by a hurricane in 1915 there was a fishing settlement on the islands, and even earlier there had been farming on the islands. The Chandeleur Island Light , built in 1895, stood as a landmark and recognizable location for mariners at sea and pilots flying over

#742257