Download Glaciers

Guided Notes
Surface Processes
Erosion & Deposition By:
Glaciers
© K. Coder 2015
26) How does moving ice erode and
deposit sediments?
• Glaciers (Movement of Ice): a naturally
formed mass of ice and snow that moves
downhill on land under the influence of
gravity
© K. Coder 2015
28) How do glaciers move?
• Glaciers will advance (move forward) when
there is more snow accumulating than melting.
• Glacier will retreat (move backward) when there
is more melting than snow accumulating.
© K. Coder 2015
29) What evidence do we have of
glacial erosion?
a) Striations: parallel scratches on bedrock
• Formed when rocks that are transported on the bottom
of the glacier leaves scratches and grooves in the
bedrock over which they pass.
• Indicate the direction the glacier moved.
29) What evidence do we have of
glacial erosion?
b) U-shaped Valley: when a glacier moves down a
mountain valley, the glacier and its load of sediment
pluck, scrape, and scour the sides of the valley changing
its profile to a broader U-shape.
30) What landscape features are evidence
that glaciers deposited sediments?
a) Till: unsorted, unlayered glacial
sediments that are deposited directly by a
glacier.
30) What landscape features are evidence
that glaciers deposited sediments?
b) Moraine: a hill of till deposited directly
from an edge or bottom of a glacier
An exposed area
of the Harbor Hill
Moraine (Long
Island, NY)
© K. Coder 2015
30) What landscape features are evidence
that glaciers deposited sediments?
c) Outwash plain: horizontal sorted layers
of glacial material in front of the glacier,
formed by the meltwater of the glacier
Moraine
Outwash plain
30) What landscape features are evidence
that glaciers deposited sediments?
d) Drumlin: glacial hills of unsorted, unlayered sediment
that are shaped like the back of a spoon by the ice
• Indicates the direction of glacial movement (toward the
gentle slope).
Glacier movement
30) What landscape features are evidence
that glaciers deposited sediments?
e) Kettle lake: when blocks of ice are left behind, form a
depression, and melt.
• If they the meltwater hits the water table, a lake will
form.
• Example in NY: Lake Ronkonkoma (Long Island)
© K. Coder 2015
30) What landscape features are evidence
that glaciers deposited sediments?
f) Erratic: rocks that have been transported to an area
(type of rock not normally found in that area)
• Example in NY: Many glacial erratic found in Central Park
Central Park, NYC Glacial Erratic
30) What landscape features are evidence
that glaciers deposited sediments?
g) Glacial Lakes
1. New York State Finger Lakes:
•
Lakes that fill in long, deep, U-shaped valleys.
•
Indicate direction of glacier movement (in a north-south position).
© K. Coder 2015
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
1. The elongated hills labeled R are most useful in determining the
(1) age of the glacier
(2) direction the glacier has moved
(3) thickness of the glacier
(4) rate at which the glacier is melting
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
2. Which feature will most likely form when the partially buried ice block melts?
(1) drumlin
(3) kettle lake
(2) moraine
(4) finger lake
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
3. The ridge of sediments from X to Y can best be described as
(1) sorted and deposited by ice
(3) unsorted and deposited by ice
(2) sorted and deposited by meltwater (4) unsorted and deposited by meltwater
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
4. Describe one difference between the arrangement of sediment in the moraines and
the arrangement of sediment in the outwash plain.
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
5. Describe one piece of evidence likely to be found on the exposed bedrock surfaces
that could indicate the direction this glacier moved.
✓ Review – Glaciers
The diagram below shows the edge of a continental glacier that is
receding. R indicates elongated hills. The ridge of sediments from X to Y
represents a landscape feature.
6. The diagram below shows a partial cross section of a valley. On this diagram, draw
a line beginning at X and ending at Y to show the shape of this valley after it was
eroded by glacial ice that flowed down the valley.
© K. Coder 2015