Arid Environment
Arid Tropical
Arid
Semi-arid :
250-500mm/yr
: less than
250mm/yr
wet period
T
fluctuates
⑳ and t
↑
e
⑧ -
drought
·
sporadic
rainfall
mPeter spikes
·
N
·
inconsistent
> unreliable
·
heavy rainfall
· intense rainfall
↑
-
7 7 T year
4
months monday
can cause
flash floods
Rainfall intensity
:
the amount of rainfall in a
given time period
Climate :
the
average weather conditions over a
long 130 yr) period
Weather Day day temperature
:
to
Different
-
Processes Arid Environments
Weathering in
MeSA :
Butte :
·
A
flat-topped
·
hill with Steep tall ,
isolated hill/mountain with Stee
sides formed by layers of to Ck vertical sides and a flat by
, top
shaped
that a re m o re resistant to erosion erosion
than the
surrounding rocks
·
final before resistant
stage the rock is
finally eroded
1 .
Sedimentary layers are formed over
millions of 1 formed
years Sedimentary rock layers are
.
over
millions of years
.
2 The cap rock (harder rock is more
resistant than the
underlying layers .
2 Erosional processes s i m i lar to those of
in the formation of
-e stee ide
mesas take place butte
.
3 There i ite espass wa te r erosion :
mainly rainfall and flash flo
floods rainfall
and that carries away sediment
water
Buttesare Susiethes
erosion .
2 mesas also bute e
and Water erosion ,
gradually erodes the softer
layers
4 Mesas features therefore
are static
.
not ,
eventually the mesa will erode away and
form a Butte .
, Zeugens Yardang
: :
long nar row hill
shaped by
ridges formed
·
shaped
,
· like mushrooms
due to erosion that removes the safter
strong winds blowing sand and
Strata layers it
rocks
against .
in ·
it
hard
thinner layers
i coriavenna i t
cause the hill +0
- collapse yardang
formed
"
hard rock
>layers of Strata
=
horizontal
Wind erosion wind erosich ice
1 .
Zeugens are primarily shalbed by wind erosion 1 .
Yardangs are primarily shalbed by wind erosion
2.consistent windsblow Samaand Streearticles a se inter a raise 2:
consistentwinds owne hasStartineas interes
a
hollows nonows
in the Softer layers of rock
Barchan Dunes :
Wadis
river
in
due shaped that
: · channels vary size
·
by Shrub r
can reach over m
S which hold the main
part of the dune in place
·
steep sided and flat bottomed
· formed by flashfloods
·
windward slope and a Steep fo
·
Wadi's channels a re sometimes utilized
leeward 33°
slope up to
agricultural purposes
·
crescent shaped 1 .
Formed by ocassional heavy rainfall
events in arid regions
1 Sand arid
deposits accumulate
.
in .
2 The rainwater does not soak into th
regions over a long period of time due * ground instead flows
W
, the rainwater ov
weathering and evosion of rocks and the sur face
sediment .
.
3 Powerful rainfall acts as an erosional agen
.
2
Prevailing winds blow across the
sandy ter rain ,
transporting sand
grains water erosich dry river channel 4 men ama arrei aton""" In
along the ground creatin
g a small , low
ridge typically oriented
cur rent
Perpendicular to the wind .
4 .
As the water continues to flow it creates channels
3 As keeps them
. wind
blowing it picks up sand grains and carries up
5 caused by
heavy rainfall
.
the to the
The erosion is continous but each event
slope dune's crest .
contributing to the
development of the Wadi's channels
The
4 and size of dunes can shift over time due to variations
a
.
e
strength and direction
Plateau > Mesa -
Butte
-water
Plateau-
W ⑰ ⑯
. See
↑
. >
A
S
Winds in Deserts
-in
⑳
⑳
.
⑦
-
watererodesarice re
·
very strong lover 20 km/h)
· turbulent (not stable)
largely from
·
come a constant direc tion
blow for period of
long time
· a
Wind Erosion
Deflation :
the process in which wind blows away loose , fine-grained Sediment particles such as sand from the Earth's sur face , leaving behind heavier mater
Abrasion
c rocks , pebble
erosion carried by wind
sandpaper surfaces and
:
They weaker rocks
ou t
particles . ac t like ,
smoothing exploiting
Role of water in the creation of landscapes in arid environments
Desert
·
rain has of run-off
a very
high amount
flash floods channels
down
through or
-
rush , gullies canyons
·
Exotic agage amountaro fragments with great crosiveawsource in another , wetter environment it
river Nile main source :
white Nile
>e
g ,
. .
·
Ephermal rivers are those that flow seasonally or after stor ms
Weathering Processes
without
weathering there would be NO CHANGE
Physical Weathering
freeze-thaw s only during winters at
night where it
gets cold enough /rare) Crystal/Salt Weathering
pressure rele ase
"Chemical frost-action"
·
Insolation
weathering 1 .
Salty water finds it's way into small cracks in the rock
heating af
· and
cooling rocks - onich skin
weathering
interioratisser remainers ras"" are
ea
expand (with heat)
contractener
,
outerlayerswarm in dark rocks
layers
good absorbers and emitter it
Arid Tropical
Arid
Semi-arid :
250-500mm/yr
: less than
250mm/yr
wet period
T
fluctuates
⑳ and t
↑
e
⑧ -
drought
·
sporadic
rainfall
mPeter spikes
·
N
·
inconsistent
> unreliable
·
heavy rainfall
· intense rainfall
↑
-
7 7 T year
4
months monday
can cause
flash floods
Rainfall intensity
:
the amount of rainfall in a
given time period
Climate :
the
average weather conditions over a
long 130 yr) period
Weather Day day temperature
:
to
Different
-
Processes Arid Environments
Weathering in
MeSA :
Butte :
·
A
flat-topped
·
hill with Steep tall ,
isolated hill/mountain with Stee
sides formed by layers of to Ck vertical sides and a flat by
, top
shaped
that a re m o re resistant to erosion erosion
than the
surrounding rocks
·
final before resistant
stage the rock is
finally eroded
1 .
Sedimentary layers are formed over
millions of 1 formed
years Sedimentary rock layers are
.
over
millions of years
.
2 The cap rock (harder rock is more
resistant than the
underlying layers .
2 Erosional processes s i m i lar to those of
in the formation of
-e stee ide
mesas take place butte
.
3 There i ite espass wa te r erosion :
mainly rainfall and flash flo
floods rainfall
and that carries away sediment
water
Buttesare Susiethes
erosion .
2 mesas also bute e
and Water erosion ,
gradually erodes the softer
layers
4 Mesas features therefore
are static
.
not ,
eventually the mesa will erode away and
form a Butte .
, Zeugens Yardang
: :
long nar row hill
shaped by
ridges formed
·
shaped
,
· like mushrooms
due to erosion that removes the safter
strong winds blowing sand and
Strata layers it
rocks
against .
in ·
it
hard
thinner layers
i coriavenna i t
cause the hill +0
- collapse yardang
formed
"
hard rock
>layers of Strata
=
horizontal
Wind erosion wind erosich ice
1 .
Zeugens are primarily shalbed by wind erosion 1 .
Yardangs are primarily shalbed by wind erosion
2.consistent windsblow Samaand Streearticles a se inter a raise 2:
consistentwinds owne hasStartineas interes
a
hollows nonows
in the Softer layers of rock
Barchan Dunes :
Wadis
river
in
due shaped that
: · channels vary size
·
by Shrub r
can reach over m
S which hold the main
part of the dune in place
·
steep sided and flat bottomed
· formed by flashfloods
·
windward slope and a Steep fo
·
Wadi's channels a re sometimes utilized
leeward 33°
slope up to
agricultural purposes
·
crescent shaped 1 .
Formed by ocassional heavy rainfall
events in arid regions
1 Sand arid
deposits accumulate
.
in .
2 The rainwater does not soak into th
regions over a long period of time due * ground instead flows
W
, the rainwater ov
weathering and evosion of rocks and the sur face
sediment .
.
3 Powerful rainfall acts as an erosional agen
.
2
Prevailing winds blow across the
sandy ter rain ,
transporting sand
grains water erosich dry river channel 4 men ama arrei aton""" In
along the ground creatin
g a small , low
ridge typically oriented
cur rent
Perpendicular to the wind .
4 .
As the water continues to flow it creates channels
3 As keeps them
. wind
blowing it picks up sand grains and carries up
5 caused by
heavy rainfall
.
the to the
The erosion is continous but each event
slope dune's crest .
contributing to the
development of the Wadi's channels
The
4 and size of dunes can shift over time due to variations
a
.
e
strength and direction
Plateau > Mesa -
Butte
-water
Plateau-
W ⑰ ⑯
. See
↑
. >
A
S
Winds in Deserts
-in
⑳
⑳
.
⑦
-
watererodesarice re
·
very strong lover 20 km/h)
· turbulent (not stable)
largely from
·
come a constant direc tion
blow for period of
long time
· a
Wind Erosion
Deflation :
the process in which wind blows away loose , fine-grained Sediment particles such as sand from the Earth's sur face , leaving behind heavier mater
Abrasion
c rocks , pebble
erosion carried by wind
sandpaper surfaces and
:
They weaker rocks
ou t
particles . ac t like ,
smoothing exploiting
Role of water in the creation of landscapes in arid environments
Desert
·
rain has of run-off
a very
high amount
flash floods channels
down
through or
-
rush , gullies canyons
·
Exotic agage amountaro fragments with great crosiveawsource in another , wetter environment it
river Nile main source :
white Nile
>e
g ,
. .
·
Ephermal rivers are those that flow seasonally or after stor ms
Weathering Processes
without
weathering there would be NO CHANGE
Physical Weathering
freeze-thaw s only during winters at
night where it
gets cold enough /rare) Crystal/Salt Weathering
pressure rele ase
"Chemical frost-action"
·
Insolation
weathering 1 .
Salty water finds it's way into small cracks in the rock
heating af
· and
cooling rocks - onich skin
weathering
interioratisser remainers ras"" are
ea
expand (with heat)
contractener
,
outerlayerswarm in dark rocks
layers
good absorbers and emitter it
