Climate change in arid and tropical humid regions
681
Northern
Dune~,.,
\,
~. ~
600 mm
I
I
Namib
Dunes
\ \\ ~~\~.-~ Southwestern
Kalahari dunes
\
\
-30oS
Atlantic
Ocean
400
Figure 25.37. Isohyets and relict and dormant dune systems in the Kalahari region. Northern Dunes:
<20,000-30,000 years ago; Southwestern Kalahari Dunes:18,000 years and southern dunes started in
the early Holocene (after Lancaster, 1981).
On the other hand, there are regions in which present and past directions are very different.
In the desert of the Kalahari the dunes are principally inactive and in the main are covered
by acacia forest, shrubs and grass. Three dune systems can be recognized on it, generated
by winds with different paleodirections (Figure 25.37) (Lancaster, 1981).
681
Northern
Dune~,.,
\,
~. ~
600 mm
I
I
Namib
Dunes
\ \\ ~~\~.-~ Southwestern
Kalahari dunes
\
\
-30oS
Atlantic
Ocean
400
Figure 25.37. Isohyets and relict and dormant dune systems in the Kalahari region. Northern Dunes:
<20,000-30,000 years ago; Southwestern Kalahari Dunes:18,000 years and southern dunes started in
the early Holocene (after Lancaster, 1981).
On the other hand, there are regions in which present and past directions are very different.
In the desert of the Kalahari the dunes are principally inactive and in the main are covered
by acacia forest, shrubs and grass. Three dune systems can be recognized on it, generated
by winds with different paleodirections (Figure 25.37) (Lancaster, 1981).