MN Physical Geography

MN Physical Geography

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Minnesota’s Natural Boundarie

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Northwest Angle

Minnesota’s Topography

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Eagle MountainHighest Point in MN (2,301’)

Minnesota’s Glaciers• 4 continental

glaciers advanced and retreated across MN

• The Pleistocene ice age was the most recent and covered most of MN

• Along the way glaciers picked up rocks and soil and transported it to the south

Minnesota’s Glaciers• The rocks and

soil left behind known as “glacial drift”

• The melting also left behind many shallow lakes

• Soils left behind are an “unsorted” mixture of soil, rocks and pebbles

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Canadian Shield

• Physical region of mostly bare bedrock and little topsoil

• Covers much of central Canada, northeastern MN and northern Wisconsin

Glacial Abrasion

“Ice-Scoured” Surface

Most of the Arrowhead region is “ice-scoured”

Boundary Waters Canoe

Area• Much bare bedrock• Soil pushed to the south

by glaciers• Little soil left behind is thin

and rocky

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Glacial Moraines

Glacial Lakes Moraine

Moraines are belts of hills that form at the edges of melting glaciers when boulders, stones and soil accumulates

Moraine and Lakes

MN Moraine

Belts• Glaciers moved

across “Moraine and Lakes” region of central MN several times leaving many moraines

• Region is hilly with many shallow lakes

• This region is covered by “Glacial drift” (soil, rocks, sand and pebbles) deposited on the land when glaciers melted

• Region is hilly with many shallow lakes

• Flattest areas are “outwash plains”

Moraine and Lakes Region

MN Moraines

Powder Ridge

Monticello’s “Little Mountain”

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Buffalo Ridge

Buffalo Ridge

Buffalo Ridge

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Driftless Area

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Driftless Area

• SE MN is described as “Driftless” because it was never touched by glaciers

Driftless Area

• Driftless area has no glacial drift

• Few lakes and many rivers and streams

• Millions of years of erosion visible

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Red River Valley

Minnesota’s 3 Continental Divides• A continental divide

is a high point of land separating the direction rivers flow

• Most of southern MN’s water drains into Mississippi and Gulf of Mexico

• Much of Arrowhead drains into Lake Superior eventually reaching Atlantic

• NW MN drains north to Lake Winnipeg and Hudson Bay

Laurentian Divide

Laurentian DivideFrom Lookout Mountain

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Lake Agassiz

Lake Duluth

Lake Minnesota

Brown’s Valley

Glacial Lake

Agassiz• When last glacier

melted the drainage path of the melt water was blocked

• Lake Agassiz formed until glacier melted

• Overflow created Minnesota River

• Sediments settled to the bottom filling in low spots and creating an extremely flat surface

Red River Valley• Red River Valley is an

extremely flat area that was once covered by Lake Agassiz

• Sediments fell to bottom creating thick and sticky soils known as “gumbo”

Red River of the North

• Why is the path of the Red River Valley so crooked?

• The land is so level the river struggles to find a consistent downhill slope

Red River of the NorthDowntown Moorhead/Fargo

Moorhead Floods Spring 2009

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Arrowhead

Driftless

Buffalo Ridge

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and Lakes

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Minnesota’s Climate

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Humid Continental

Wide ranges in temperatures

MN Temperatures

Hot Summers and Cold Winters

MN Precipitatio

n• Most of the

moisture that falls in MN comes from Gulf of Mexico

• Precipitation greatest in the SE and least in the NW

Jet Stream

March 29, 18814 Distinct Seasons

MN

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Season

Consecutive Days Averaging 43oF or More

Only southern MN has a long enough growing season for corn

Minnesota’s Natural

Vegetation

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Coniferous Forests

Deciduous Forests

Prairie

MN Natural Vegetation• Natural vegetation is an indicator of

a region’s precipitation, temperatures and soil

• NE MN mostly coniferous forest• Central MN mostly deciduous• S & W MN mostly prairie

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70% of MN’s commercial forest industry located in NE MN

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MN Soil Fertility

• Best soils are found in the southern and western MN

• Least fertile soils are found in northeast MN (thin, rocky and acidic podzol soils)

Minnesota’s Natural Regions

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Arrowhead

Dairy Belt

Corn Belt

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MN’s Natural Regions

Arrowhead

Dairy Belt

Corn Belt

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Percent of Land in

FarmsArrowhead

Arrowhead• Ice-scoured by

glaciers• Thin and rocky

soils• Cool temps and short

growing season• Coniferous forest• Podzol (acidic) soils• Little agriculture• Much land remains

in forests• Paper, mining and

tourism impotant economic activities

MN’s Natural Regions

Arrowhead

Dairy Belt

Corn Belt

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Dairy Belt

• Hilly topography• Glacial moraines• Many lakes and

marshes• Soil better than

Arrowhead but not as good as the Corn Belt

• Most farmers raise livestock, particularly dairy cattle

MN’s Agricultural Regions

Arrowhead

Dairy Belt

Corn Belt

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Percent of Land in

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Red River Valley

• Once the bottom of glacial Lake Agassiz

• Extremely flat• Spring floods common• Thick and sticky

“gumbo” soils• Soils are soil to dry in

the spring• Short growing

season

MN’s Natural Regions

Arrowhead

Dairy Belt

Corn Belt

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Percent of Land in

Farms

Corn Belt

Corn BeltBuffalo RidgeBuffalo Ridge

Rock CountyRock County

Corn Belt

• Relatively flat topography except “Buffalo Ridge” in southwest corner

• Thick, black soils

• Long growing season

• Adequate precipitation

• One of the best agricultural regions in the nation

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Corn Belt

Dairy Belt

Arrowhead

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