AGENTS OF GRADATION

1. Dear Sir/Madam
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2. AGENTS OF GRADATION

3. AGENTS OF GRADATION
• The earth surface is very uneven.
• There are various landforms found on the
earth surface.
• Would you name some of the landforms
which you see on the earth surface ?
• …………………

4. These features are the result
of
various endogenic and exogenic
forces

5. Exogenic forces include :
Weathering
• Rocks are weaken by
the process of
Weathering.
Erosion
• Such weak rocks are
easily eroded and
transported by the
agents of gradation.

6. Agents of gradation
try to level the ground which is
made uneven by endogenic forces.

7. There are five agents of gradation :
• Running water
• Ground water
• Moving snow
• Wind &
• Sea waves
Today we would be looking into the work of
Moving snow / ice.

8. Gl and
Landforms
by glacier
are found in areas of higher
latitudes or
higher altitudes

9. What is a glacier?
• A glacier is simply the existence of year-
round ice on the landscape.
• There are two broad types: continental and
alpine.
How do glaciers form?
• Glaciers form whenever snowfall exceeds
snowmelt year after year. The snow
accumulates incrementally, pressure increases,
and it is changed into névé and then ice by
this pressure.

10. Why is a glacier the only thing that is
ever comiEROSIONAL
FEATURESgoing at the same
time?

13. Franz Joseph Glacier and Outwash Plain, New Zealand

15. Erosion by Glaciers
• volume and speed determines
amount of erosion.
• erodes slightly more effectively
than water.
• plucking and abrasion (rock-
tipped blade).
• polishing and striations.
• Continental glaciers remove
all soil, plants, and small hills.
• Alpine glaciers change V-
shaped
valleys to U-shaped.

16. DdepoDsition by GDlaciers
• drift is any material deposited by
glaciers or their meltwater.
•Till is that unsorted material that is
deposited directly by ice.
• Moraines are linear features
deposited at bottom or along sides
of glaciers.
• Glacial erratics are enormous
boulders transported and deposited
by glaciers, often far from their
source region.

18. Deposition by Glaciers
• drift is any material deposited by
glaciers or their meltwater.
•Till is that unsorted material that is
deposited directly by ice.
• Moraines are linear features
deposited at bottom or along sides
of glaciers.
• Glacial erratics are enormous
boulders transported and deposited
by glaciers, often far from their
source region.

20. Moraines

23. Finger Lakes Region, New York

24. Erosion by Glaciers
• volume and speed determines
amount of erosion.
• erodes slightly more effectively
than water.
• plucking and abrasion (rock-
tipped blade).
• polishing and striations.
• Continental glaciers remove
all soil, plants, and small hills.
• Alpine glaciers change V-
shaped
valleys to U-shaped.

27. Continental Glaciers or Ice Sheets
• only two true ice sheets exist
today: Greenland and
Antarctica
• where they meet the sea
they can form ice sheets.
• vary in thickness from
hundreds of feet to two miles
deep
• scour away all soil and
vegetation and dramatically
reshape the landscape and
ecology of large regions.
• much change occurs in the
periglacial environment.
Ellesmere Island, Canada

28. Dear Sir/Madam
For more
Please visit my YouTube Channel to learn computer
https://www.youtube.com/yka39
For class IX & X Computer Class visit-:
www.it402.com