Gifts of the Glaciers
Glacial Landforms
Gifts of the Glaciers

Moving ice of glacier was responsible for
water, landforms, and soil characteristics
and patterns of today
 Sculpturing
 Erosion
of bedrock materials
of bedrock
 Deposition
of glacial drift
Glacial Landforms

Glacial landforms dominate the Great
Lakes region
 Northeastern
 Northwest
 Most
Illinois
Indiana
of WI, MI, MN, and Ontario
Glacial Landforms

Effects of moving ice:
 Leveled
 Filled

off the existing hills
in valleys
 Blocked
the drainage of the rivers
 Gouged
out major basins (ex: GLB)
Processes involved: grinding, erosion,
leveling, and depositing.
Glaciers perform, in many ways, like an excavator. Although
they can push weak material, like gravel, like a bulldozer
blade, they are far more likely to lift material out of place, like
a backhoe, or scratch it in place, like a ripper. And, like a
bulldozer, glaciers are poor at eroding rock unless it is
already weakened.
Glacial Erosion

Rock Failure:
 The
first step in
glacial erosion is rock
failure.
 Water, ice causes
cracks in rocks
Glacial Erosion

Two main types of glacial erosion
 Plucking
(analagous to a backhoe).
 Abrasion

Plucked debris in basal ice grinds into the bedrock,
just like sandpaper across wood
Plucking
Abrasion
Glacial Erosion

Glacial / Fluvial Processes: At the bed of
warm-based glaciers, water is present in it’s fluid
state.
 This
water flows underneath the glacier and assists
erosion by removing erosional products, especially
silt.
 When water collects into subglacial channels, it can
be sufficiently powerful to erode by itself
Subglacial view of basal debris
Glacial Outwash Stream
Glacial Outwash Stream
Glacial Landforms

Material deposited by glaciers is called
drift
 Till
is deposited directly from glacier
 Outwash is deposited by meltwater

In summer, meltwater carried along “rock flour
sediments

In winter these were blown by wind

Left thick beds of loess downwind from major river
valleys
Glacial Drift
Till that has melted out from the dark
striped basal ice layer.
Glacial Till – North Shore L. Superior
Outwash plain and
braided streams
Outwash plain
Outwash sediments
Till exposure (dark tan) located above
outwash sediments (light tan)
Glacial Grooves on Kelleys Island, Ohio
Glacial Striations on
Canadian Shield Bedrock
Large Glacial Erratic
Large Glacial Erratic
Glacial Landforms

Rock, gravel, sand, and silt left behind by
melting glaciers formed mounds, ridges, and
thick windblown deposits.

Moraines mark re-advances of glacier and
when glacier stalled as it retreated
 Accumulated
by ice
drift is pushed into higher mounds
Glacial Landforms

End Moraines — During periods when the rate
of ice advance nearly equaled that of melting,
huge mounds of sand and gravel piled up in
curved ridges along the glacier's edge.
End Moraine
Ground Moraine
End Moraines
Valparaiso morainic
system
Marseilles morainic system
The end moraines from the
Wisconsin glaciation can be
seen in Northeastern Illinois.
Illinois Moraines
Glacial Landforms

Ground Moraines - Ground moraines are
formed as till is deposited directly beneath a
glacier; between the ice and the underlying
rock.

Ground moraines are located behind end
moraines.
Form gently rolling to flat countryside.

End Moraine
Ground Moraine
Ground Moraine
Ground Moraine
Ground Moraine with Kettles
Moraines


End moraines - western suburbs of Chicago
 Form at melting end of glacier as till piles up
 Belts of rolling or rugged hills with intervening
swales, swamps and lakes
Ground moraines - DeKalb county
 Form as ice front retreats and leaves a flatter
deposit
 Gently undulating lands
End Moraine
Ground Moraine
Moraines

Recessional moraines are formed when
the ice stands still and melts.
Recessional Moraines
Moraines

Push Moraine - A ridge or
pile of unstratified glacial
sediment that is formed in
front of the ice margin by
the terminus of an
advancing glacier,
bulldozing sediment in its
path.
Kettles



Kettles — Depressions formed when ice broke
into chunks that became buried in sediment.
When the ice block melted, it left a depression,
which sometimes filled with water to form kettle
lakes.
Kettle lakes are common in northern and central
Illinois.
Ice Block/Kettle Hole Lakes

Kettle Hole Lakes
 These
are usually deep lakes
Many still have water
 Steep sides
 Most Great Lakes region lakes are kettle hole
lakes
 Minnesota = Land of 10,000 Lakes
 Volo Bog formed in a kettle

Volo Bog
Iceland – Kettle forming with ice
block still in place.
Kettle within Morainal Ridges
Outwash Plains

Outwash Plains — At the glacial front, water
flowing from underneath the ice formed level
plains of fine sediment.
Outwash plain and
braided streams
Outwash plain
Drumlins

Drumlins are low, smoothly rounded hill of
compact glacial till, built under the margin of the
ice and shaped by its flow
 Sculpted
by active ice during a re-advance over an
old till plain
 Arranged
more or less parallel
 Separated
or swales
from each other by poorly drained troughs
Drumlins
The Antrim-Charlevoix drumlin field
is one of the largest in the midwest.
Drumlins at Kejimkujik Provincial Park,
Nova Scotia, CA
Drumlin Fields along coast of Michigan
Drumlins near Auburn, New York,
looking southeast. Owasco Lake is
in the upper right
Eskers



Eskers are long narrow hills that look like
abandoned railway embankments
Long, winding ridges of sand and gravel formed
in waterways under the glaciers.
Long narrow winding ridges of stratified gravel,
sand and silt
 Formed
under stagnant rather than moving ice
 Form low, sinuous hills that can stretch for miles and
often resemble snakes when seen from the air
Eskers
Esker
Esker
Esker cross-section. Eskers are often
mined for gravel
Kames


Kames - Smaller mounds of sand and gravel
formed where sediment filled cracks in the ice.
Stratified hills of cobble, gravel, sand, and silt
 Formed
when meltwater plunges into crevasses/
moulins on the ice surface or at the ice front and
deposits its load of sediment

Conical (more or less) sometimes ridgelike in
shape

Series of kames at Glacial Park in McHenry Co.
Kames
A moulin (glacier mill) on a modern glacier
Prairie Kame in Kane County
Camelback Kame at Glacial Park, McHenry Co. Illinois
Moulin Kame in the Kettle Moraine, 4
miles northeast of Dundee, WI.
Conner Hill, looking southwest
Glacial Soils

Regional soils are also the result of glacial
deposits
 Nonglaciated
areas
Driftless area of SW WI
 Limestone bedrock exposure areas of sw Cook
and western Will counties

 Ice
picks up rocks and other debris
 Ice grinds rock bedrock into fine silty deposits
called “rock flour” or loess (luss)
Loess Deposits

Loess Deposits — During the cold seasons, the
flow of glacial meltwater slowed. Fine silt that
had been deposited on the outwash plain and
along river channels leading from the glacier
was exposed and dried out. Winds blew the dust
to surrounding areas where it slowly grew into
thick silt deposits called loess. Vertical faces of
loess, sometimes over 30 meters (about 100 ft.)
high, can be seen along the Mississippi and
Illinois River valleys.
Loess bluff near Edwardsville, IL.
Illinois loess deposits
Glacial lake plains



Sediments of glacial and proglacial lakes, also river
sediments that flowed into lakes
May have sand dunes far from any modern water source
 Beach ridges
 Visible at Indiana and Illinois Dunes
Often have special soils
 Marl (calcium carbonate: mined for cement and fertilizer)
 Special crops farmed on these soils
 Navy beans
 Sugar beets
 Soy beans
Glacial Lake Plain Bounded by Moraine