Mississippi Valley type The central plains of North Americarunning from the Appalachian Mountains on the east to the Rocky Mountains on the west, are underlain by nearly flat sedimentary rocks that were laid down on a now-covered basement of igneous and metamorphic rocks. The cover of sedimentary rocks, which have been little changed since they were deposited, contains numerous strata of limestoneand within the limestones near the bottom of the pile is found a distinctive class of mineral deposit. Because the central plains coincide closely with the drainage basin of the Mississippi Riverthis class of deposit has come to be called the Mississippi Valley type MVT. MVT deposits are always in limestones and are generally located near the edges of sedimentary basins or around the edges of what were islands or high points in the seafloor when the limestone was deposited.
See Article History Mississippi River, the longest river of North Americadraining with its major tributaries an area of approximately 1. The Mississippi River lies entirely within the United States. Rising in Lake Itasca in Minnesotait flows almost due south across the continental interior, collecting the waters of its major tributaries, the Missouri River to the west and the Ohio River to the eastapproximately halfway along its journey to the Gulf of Mexico through a vast delta southeast of New Orleansa total distance of 2, miles 3, km from its source.
With its tributaries, the Mississippi drains all or part of 31 U. Cbkarim Although the Mississippi can be ranked as the fourth longest river in the world by adding the length of the Missouri- Jefferson Red Rock system to the Mississippi downstream of the Missouri-Mississippi confluence—for a combined length of 3, miles 5, km —the 2,mile length of the Mississippi proper is comfortably exceeded by 19 other rivers.
Grant —with that of the celebrated author Mark Twain. The Mississippi River basin and its drainage network.
On the basis of physical characteristics, the Mississippi River can be divided into four distinct reaches, or sections. In its headwaters, from the source to the head of navigation at St. PaulMinnesota, the Mississippi is a clear, fresh stream winding its unassuming way through low countryside dotted with lakes and marshes.
The upper Mississippi reach extends from St. Paul to the mouth of the Missouri River near St. Below the Missouri River junction, the middle Mississippi follows a mile km course to the mouth of the Ohio River. The turbulent, cloudy-to-muddy, and flotsam-laden Missouri, especially when in flood, adds impetus as well as enormous quantities of silt to the clearer Mississippi.
Beyond the confluence with the Ohio at CairoIllinois, the lower Mississippi attains its full grandeur. Where these two mighty rivers meet, the Ohio is actually the larger; thus, below the Ohio confluence the Mississippi swells to more than twice the size it is above.
Minneapolis, MinnesotaMinneapolis, Minnesota, U. Louis, MissouriGateway Arch and downtown St. Physical features Physiography The geology and physical geography of the Mississippi drainage area are essentially those of the Interior Lowlands and Great Plains of North America.
Fringes also touch upon the Rocky and Appalachian mountain systems and upon the rim of the Canadian Laurentian Shield to the north. Rising in western uplands, notably in the foothills of the Rockies, rivers such as the RedArkansasKansasPlatteand Missouri remove considerable silt loads from the rolling expanses of the Great Plains.
These tributaries meander and braid across a wide, gently sloping mantle of unconsolidated materials, laid down over rock beds of the Cretaceous Period i. The sandy sediments, moreover, offer little resistance to erosionso that many of these rivers are only braided in their courses.
Most of this group, including the KentuckyGreenCumberlandand Tennessee rivers, flows via well-defined valleys into the Ohio and thence into the Mississippi. The erosive capacity of these rivers varies in relation to the geologic structure of their basins. These consist of harder rocks in the higher elevations and a softer sill of limestone of the Late Carboniferous Period i.
The third contributory area of the Mississippi also differs from the other two.
The upper Mississippi gathers its strength in a region marked by glacial action. After the great ice sheets of the Wisconsin Glacial Stage had put down layers of debris across much of Minnesota, Wisconsin, northern Illinois, and northern Iowa, huge quantities of meltwater flowed south, washing channels through this debris.
Today the upper Mississippi and its tributaries, the WisconsinSt. CroixRockand Illinois rivers, all trace the lines of these former sluiceways.
Pouring southward, the glacial meltwaters were joined by the proto-Missouri and Ohio rivers. The combined waters then enlarged the great north-south trough along which the lower Mississippi now flows. Some 1, miles 1, km long, this trough is 25 to miles 40 to km wide and bounded by escarpments rising up to feet 60 metres above the valley floor.
Geologic studies have revealed that the floor of the glacial trough was later buried by a deep layer of material washed out from an ice sheet and dumped to a thickness of to feet 30 to 90 metres in the central section.
There, at the tip of the drainage funnel, millions of years of sedimentation have spilled out across the floor of the Gulf of Mexicoforming cones of sediment that total mi in radius and 30, square miles 77, square km in area. The surface expression of the many sub-deltas is the Mississippi delta, with an area exceeding 11, square miles 28, square km.
Stretching its distributaries into the gulfthe Mississippi once delivered some million tons of sediment there each year, most of it as silt.Note: If you are planning a visit to any of the ferries in the Middle Mississippi Valley and believe the ferries might not be operating due to flood conditions or ice please call the numbers below for current information.
Note: If fees and times are an issue please call ahead to confirm details. Index to Middle Mississippi River Valley Ferries. Good old-fashioned fun can be found at the many regional and county fairs that are held in the Middle Mississippi River Valley!
Mississippi River, the longest river of North America, draining with its major tributaries an area of approximately million square miles ( million square km), or about one-eighth of the entire continent.
The Mississippi River lies entirely within the United States. Rising in Lake Itasca in. The Mississippi River is the chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system.
The stream is entirely within the United States (although its drainage basin reaches into Canada), its source is Lake Itasca in northern Minnesota and it flows generally south for 2, miles (3, km) to the Mississippi River Delta in.
The term Middle Mississippian is also used to describe the core of the classic Mississippian culture area. This area covers the central Mississippi River Valley, the lower Ohio River Valley, and most of the Mid-South area, including western and central Kentucky, western Tennessee, and northern Alabama and .
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