Glacial LandscapesGlacial Landscapes

Glacier = large Glacier = large movingmoving mass of ice. mass of ice. Glaciers erode, transport and deposit massive Glaciers erode, transport and deposit massive

amount of sediment called amount of sediment called till.till. Important to NYS. (last ice age was 10,000 y.a.)Important to NYS. (last ice age was 10,000 y.a.) 2 Types of glaciers:2 Types of glaciers:

Valley glaciersValley glaciers

Continental glaciersContinental glaciers

Valley GlaciersValley Glaciers

Smaller scale glaciers that form at high Smaller scale glaciers that form at high elevations.elevations.

Flow starts when accumulated snow and ice Flow starts when accumulated snow and ice becomes too massive and flows.becomes too massive and flows.

Speed of flow is dependent on slope of Speed of flow is dependent on slope of valley floor.valley floor.

Sides and bottom of valley glacier move Sides and bottom of valley glacier move slower than the middle. Why?slower than the middle. Why?

Continental GlaciersContinental Glaciers

Glaciers that cover broad, continent sized Glaciers that cover broad, continent sized areas.areas.

These glaciers move because they are very These glaciers move because they are very thick in the center and flow out from that thick in the center and flow out from that thick center point. Why?thick center point. Why?

The Laurentide Ice Sheet covered NYS The Laurentide Ice Sheet covered NYS about 10,000 y.a. about 10,000 y.a.

Glacier MovementGlacier Movement

Advance – glacier moves forward.Advance – glacier moves forward. Retreat – glacier appears to move Retreat – glacier appears to move

backward.backward.

In reality during a In reality during a glacial retreatglacial retreat, the glacier is , the glacier is still moving forward under gravity, but it is still moving forward under gravity, but it is melting faster that its forward motion.melting faster that its forward motion.

Glacial DepositionGlacial DepositionMost glaciers push, carry and drag great Most glaciers push, carry and drag great

quantities of sediment. Sediments carried quantities of sediment. Sediments carried by glaciers or the melt-water of glaciers is by glaciers or the melt-water of glaciers is called called glacial driftglacial drift. There are 2 main types . There are 2 main types of drift:of drift:

1.       Once a glacier retreats the unsorted 1.       Once a glacier retreats the unsorted material deposited directly by material deposited directly by

the glacier the glacier is called is called tilltill. .

2.2. Sorted material deposited by the Sorted material deposited by the melt-melt- water is called water is called outwashoutwash..

Glacial DepositionGlacial Deposition

Glacial DepositionGlacial Deposition

MoraineMoraine – small ridge of till left over by glaciers. – small ridge of till left over by glaciers.

End moraineEnd moraine – small ridge of till located at the front of a glacier. – small ridge of till located at the front of a glacier.  Terminal moraineTerminal moraine – small ridge of till left at the furthest extent – small ridge of till left at the furthest extent

of the glacial advance.of the glacial advance.  Recessional moraineRecessional moraine – a series of ridges left behind as the glacier – a series of ridges left behind as the glacier

retreats. (formed during pauses) retreats. (formed during pauses)             

Glacial DepositionGlacial Deposition

Lateral moraineLateral moraine – small ridge of till left at the sides of – small ridge of till left at the sides of a glacier.a glacier.

  Medial moraineMedial moraine – small ridges of till formed at the – small ridges of till formed at the

meeting point of two valley glaciers (center).meeting point of two valley glaciers (center).  Ground moraineGround moraine – low mound of till left behind under – low mound of till left behind under

a glacier.a glacier.  DrumlinDrumlin – oblong shaped hill formed during a glacial – oblong shaped hill formed during a glacial

retreat. retreat.

End Moraine and Lateral MoraineEnd Moraine and Lateral Moraine

Lateral moraine and Medial moraineLateral moraine and Medial moraine

Retreating glacier and ice-marginal lakeRetreating glacier and ice-marginal lake

DrumlinDrumlin

Glacial DepositionGlacial Deposition

Outwash plainOutwash plain – plain of till in front of glacier, fed – plain of till in front of glacier, fed by melt-water.by melt-water.

  

Kettle Kettle – depressions left in the outwash plain by – depressions left in the outwash plain by large blocks of ice that break off the glacier.large blocks of ice that break off the glacier.

  

EskerEsker – winding ridge of till that has filled in an old – winding ridge of till that has filled in an old melt-water tunnel. (formed under a glacier)melt-water tunnel. (formed under a glacier)

Outwash and braided melt water Outwash and braided melt water channelschannels

KettlesKettles

EskerEsker

Glacial Landscapes on MountainsGlacial Landscapes on Mountains

CirqueCirque – deep depression carved out of – deep depression carved out of existing mountains by valley glaciers.existing mountains by valley glaciers.

HornHorn – steepened peak left behind after a – steepened peak left behind after a glacier erodes a mountain on 3 sides.glacier erodes a mountain on 3 sides.

AreteArete – A ridge of mountain left behind after – A ridge of mountain left behind after glacial erosion, usually forming where two glacial erosion, usually forming where two cirques on opposite sides of a valley meet.cirques on opposite sides of a valley meet.

Cirque and hornCirque and horn

AretesAretes

Glacial LandscapesGlacial Landscapes

Other Important Points to Know:

1. Glaciers carve “U-Shaped” valleys as they erode.

2. Glacier can leave behind parallel scratches in solid bedrock called “striations”.

3. U-Shaped valleys that meet or join into other lower valleys can form, hanging valleys that rise higher than the lower valley.