Transcript Distribution of Cold Environments PPT

Distribution of Cold
Extreme Environments
Latitude and the overhead
sun
The Tricellular Model and
Precipiation Patterns
Mountain Environments

Fold and Thrust Mountain
Those like the Alps and the
Himalayas form at Collision plateBelts
Boundaries as a direct result of
the collision between two
continental plates. The Alps are
forming due to the collision of the
African Plate with the Eurasian
plate and the Himalayas are
forming due to the collision
between the Indo- Australian
Plate with the Eurasian. In both
cases the density of the plates
counteract each other and so the
crust is forced to fold, crease
and lift upwards like an
accordion. If the process of
collision continues vast
mountains ranges can form.
Strike/Slip
Mountain Belts
As two plates move
alongside each other either in
opposite directions or at
different speeds relative to
each other great friction and
pressure develops. At points
along the boundary where
there is a significant change
in direction, collision
processes are at work and so
strike-slip mountain belts like
the Rocky mountains form.
Fault-Block Mountains
Form at Constructive Plate Boundaries
or Rift Valleys where two plates are
moving apart. They also form in very
localised regions along complex fault
zones. For example the Sierra Nevada
Range is formed through Fault- Block
processes. In this example plates
move apart through tensional stress in
the fault zone. Sections of the crust
sink to reveal great raised scarps on
the landscape. The relief shows a
fluctuating pattern of elevation and
depression known as Range and
Basin landscapes.
Altitude and Temperature
As you climb a mountain, you can expect the air temperature to
decrease by 6.5ºC for every 1000 metres you gain. This is called
the environmental lapse rate. For example if air temperature is
30ºC at sea level as shown to the left you can expect temperature
to have fallen to 10.5ºC at the altitude of 3000 metres. This
phenomena takes place firstly, due to the source of heating being
at surface level and secondly because of differences in pressure.
 Air at higher altitude is cooler because the pressure is
lower. Gases expand at lower pressures. As a gas
expands, the molecules (and atoms) within it move
more slowly. Since air temperature is just a measure of
how fast the molecules in air are moving, the rate of
motion of molecules and the temperature are both
lower at higher elevations.
 Secondly, the troposphere is warmest at sea level and cools
upward because the Earth’s atmosphere is heated from
below. The atmosphere is mostly heated by the surface of
the earth below and not directly by the Sun from above,
even though the upper atmosphere is closer to the Sun.
Therefore the higher you rise in altitude the less surface
area there is to heat the air around it. The resulting
environment is one of greater extremity proportional to
altitude. This means colder and more extreme atmospheric
conditions combined with steep and weathered surfaces.
 High mountains are possibly the most extreme of all
environments, with unpredictable weather including
heavy snowfall, extreme low temperatures and high
wind speeds. This results in high rates of physical
weathering, which creates the most stunning
landscapes imaginable, with steep faced cliffs and
razor-sharp aretes. This makes them the most remote
and inhospitable of places for all mankind.