Salt Lakes and Salt Pans Particularly relevant to the AQA Geography A-level 'Hot Deserts and their Margins'

1. Makgadikgadi Pans
Botswana

3. Hundreds of new fish
species are thought to
have originated in this
massive lake

4. Eventually all the water dried
up,
Over thousands of years
the climate become hotter
and drier and the lake lost
its water source

5. As the water evaporated Lake Makgadikgadi
gradually begun to dry up, leaving only a thick layer
of salt, sand and animal remains

6. All that is left today is a
series of huge salt flats
covering 12,000 km2

7. Although the main lake has dried up there is still
enough water during the rainy season to provide
an important breeding ground for flamingos

8. The Makgadikgadi
Salt Pans are so
huge they can be
seen from space!
Can you see
them?

9. Can you name any
other features or
countries?
Makgadikgadi
Salt Pans

10. Can you name any
other features or
countries?
Kalahari Desert
Makgadikgadi
Salt Pans
Okavango Delta
Lake Kariba
Lake Malawi
Cape Fold Mountains

11. Let’s find out what
the Makgadikgadi is
like… (Otherwise you
won’t be able to do your
exam and you will DIE!)

12. Top Gear Botswana Special
Make sure you note
down any key facts or
characteristics that
are mentioned as you
will be tested after!

13. MA K ADI K ADI
Just add a G (for top
Gear) after each K
G G

14. Can you help me
remember any key
information from
the video?

15. What are the
characteristics of a
salt lake?
A salt lake is a lake that has a
very high salt content
It can vary greatly in size. Some are very large and permanently have water, e.g. the
Dead Sea between Jordan and Palestine/Israel, which is fed by the River Jordan.
Others are much smaller or shallower and only exist when it rains (ephemeral salt lakes).
In the dry season there is just a salt pan.
A salt pan is a large, flat, featureless plain with a hard crust of salt on the surface giving it
a white appearance. Underneath this hard crust is a thick layer or mud and sediment.

16. How do salt lakes form?
A salt lake may form when rainwater
collects in a deflation hollow
Or it could be the end point of river in an endoreic drainage basin (where the water
drains into a lake instead of the sea) such as the Dead Sea. Makgadikgadi also used to be
a permanent lake fed by a river.
If the rate of evaporation exceeds the rate at which water is added the lake will gradually
dry up and become a salt pan/salt flat.

17. How do salt lakes form?
As the water evaporates it leaves behinds salt minerals. These are precipitated from the
salts that were dissolved in the water.
At the same time the evaporation encourages capillary action – the upward movement
of water in the soil. This brings even more salt to the surface where it accumulates as a
hard crust of salt. This is usually white in colour and may crack into polygonal shapes.
More and more salt accumulates as ephemeral salt lakes form and dry up over and over.

18. Salt flats provide breeding grounds, natural resources of salt
minerals as well as flat land for speed records!
They can take thousands of years to form, which is why
environmentalists accused Jeremy Clarkson of permanently
scarring the Makgadikgadi salt pans and encouraging
environmentally insensitive behaviour.
Oops!

19. Salt Mining in
Salar de Uyuni, Bolivia

20. The Dead Sea

21. Hiro Koiso

22. Creative photography in
the Uyuni Salt Flats
showing the polygonal
cracks on the surface

23. Can you
answer this
question?
Describe the characteristics and explain the
formation of salt lakes
(7 marks)

24. 1. Start by describing
what they’re like
e.g. size, shape, colour,
location, if/when they
contain water
Describe the characteristics and explain the
formation of salt lakes (7 marks)
2. Then explain how
they are formed
Try to give a sequence
of steps and give a
sense of time using
words like ‘gradually’
Try to use key words
and give some specific
examples
Crust
Ephemeral
Capillary action
Evaporation
Deflation hollow
Endoreic
Salt pan
Polygonal
Precipitated
Perennial