LITHOSPHERE
In this unit we will look at…
•
•
•
Glaciated Landscapes
Limestone Landscapes
Coastal Landscapes
You will…
1.
2.
3.
4.
5.
Learn about the landforms associated with each landscape
Have to be able to describe and explain the formation of the
landforms
Have to be able to draw sketches of some landforms
Have to know the processes that shaped these landscapes
Learn how to identify landscape features on an O.S map
Glaciated Landscapes
Throughout the lithosphere unit you will use O.S
maps to identify features, using 4 and 6 figure
grid references.
Task 1;
Look at the O.S map of the Cairngorms on the
next slide and describe the evidence which
shows that this area was once affected by
glaciation.
Find features of glaciation on the map extract,
and use 4 and 6 figure grid references to show
where the features are on the map.
Corrie
Remember!
Contour lines are very close
together showing very steep
land.
Arete
The contour lines are
curved showing a bowlshape
Sometimes a tarn is evident
U-Shaped Valley
Where two corries form
back to back.
Contour lines are very
close together showing
very steep land. There is a
long strip of white in the
middle showing flat land.
The arete (ridge) is
shown as a black rugged
line
D
C
B
08
E
07
07
A
06
06
05
05
04
03
91
92
93
94
95
96
97
98
99
D
U-Shaped Valley
and Mis fit stream
C
B
Tarn
08
E
corries
07
07
A
06
06
corries
05
05
Tarn
04
fiord
03
91
92
Arete
93
94
95
96
97
98
99
3 Corries
3 Corries
2 Corries
U – Shaped Valley
Misfit Stream
Fiord
U-shaped valleys and
corries are features of
glacial erosion.
But what processes have
shaped these landforms,
and other landforms of
glacial erosion?
Plucking;
•
When rocks have become weakened by freeze-thaw, the moving glacier freezes onto
the valley sides and floor
•
As the glacier moves downslope by gravity, the rocks that the glacier has frozen onto
are torn away from the valley sides and floor
•
This produces rough, jagged rock surfaces
•
By tearing away huge rocks, the valley sides are left very steep and the base very flat.
Abrasion;
•
The jagged rocks and stones embedded at the base of the glacier or ice sheet,
scrapes along the valley sides and base.
•
This is like a sandpapering effect, where the valleys sides and base become smooth
•
Where the rocks embedded in the glacier scratch along the surface, striations may be
left on the rock surface. Striations are scratch marks on the rock surface.
Freeze-Thaw (Frost Action)
•Occurs when temperature rise and fall
•When it rains, snows etc, water enters the cracks in the rocks
•When temperatures fall below zero, possibly at night, the water freezes
and expands; frozen water can expand by 9%. This exerts huge pressure
on the rock.
•When temperatures rise again, during the day, the ice melts, releasing the
pressure on the rocks.
•This continuous freezing and thawing causes the rocks to become very
weak, cracks widen and pieces of rock break off.
•Rocks that have broken off, fall to the foot of the slope, shatter and
become scree or talus.
Before Glaciation
During Glaciation
After Glaciation
Homework
For tomorrow…
Answer the 1998 past paper question on
Glaciation (3b)
3b) is worth 4 marks so you are looking
for 8 points to make
Task 1:
Using the information that you have just heard and your
notes, answer the following question;
Select one feature of glacial erosion
and explain the processes involved in the
formation of this feature.
Annotated diagrams may be used.
3 marks