MN Physical Geography
Feb 07, 2016
MN Physical Geography
Min
nesota
fro
m
Sp
ace
Minnesota’s Natural Boundarie
s
Northwest Angle
Minnesota’s Topography
Min
nesota
Relief
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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
Gla
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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
Min
nesota
Relief
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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”
Min
nesota
Relief
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Buffalo Ridge
Buffalo Ridge
Buffalo Ridge
Min
nesota
Relief
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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
Min
nesota
Relief
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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
MN
’s G
lacia
l Lakes
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
Red
Riv
er V
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Arrowhead
Driftless
Buffalo Ridge
MN
’s P
hysic
al
Reg
ion
sMoraine
and Lakes
MN
Top
og
rap
hy
Minnesota’s Climate
Min
neap
olis
Clim
ate
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
Gro
win
g
Season
Consecutive Days Averaging 43oF or More
Only southern MN has a long enough growing season for corn
Minnesota’s Natural
Vegetation
MN
Natu
ral
Veg
eta
tion
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
Perc
en
t of
MN
in
C
om
merc
ial Fore
sts
70% of MN’s commercial forest industry located in NE MN
Natu
ral S
oil
Fert
ilit
y
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
MN
Natu
ral
Veg
eta
tion
Arrowhead
Dairy Belt
Corn Belt
Red
Riv
er V
alle
y
MN’s Natural Regions
Arrowhead
Dairy Belt
Corn Belt
Red
Riv
er
Valley
MN
Top
og
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hy
Natu
ral S
oil
Fert
ilit
y
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
Red
Riv
er
Valley
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
Red
Riv
er
Valley
Percent of Land in
Farms
Red
Riv
er
Valle
y
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
Red
Riv
er
Valley
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
MN
’s A
gri
cu
ltu
ral
Reg
ion
s
Corn Belt
Dairy Belt
Arrowhead
Red
Riv
er V
alle
y