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When you look at a
landscape, it is good to wonder about its origin and
evolution. Why does it have that shape? Why is it so different
from another one? Which forces managed to model it? What was
it like in the past? How will it be in the future? Why does
the vegetation change?
The answers to these questions let us interpret the landscape,
i.e., to know it through the comprehension of the processes
which have taken place in it. And those processes are the
consequence of the relationships between natural and human
elements that belong to the landscape.
This let´s us value the delicate balance of nature and have a
more harmonious relationship with it.
In the origin of landscapes, two kind of forces can be seen,
some constructive and others destructive. Among the first
ones, we find the forces inside Earth -they lift continents,
mountains and bend or break the Earth´s crust. Those
elevations later receive the impact of external forces and
weather factors. The water (ice, rivers, rainfall) and the
wind, helped by the force of gravity and the type of soil,
transform the topography, the base for the development of
vegetation and fauna.
The man is a relevant agent of change, responsible for many
unbalances, sometimes with serious consequences for humanity.
For example, a huge cut down of a wood in a slope of unstable
ground.
The amazing geography of this region is, in the first place,
the result of the action of glaciers. The elevated land around
the huge valleys they excavated were proper sites for people
settlements.
Climate evolution made the glaciers move backwards and fill
the holes creating large lakes. Lake Lacar has a depth of
277m.
Before and after glaciations, volcanoes added a new element to
build landscape. The rocks - fused by pressure and temperature
- were chewed out leaving slag-heaps or, in other cases, a
stratum of ashes, which affected the topography, vegetation
and fluvial systems. Finally, hydraulic and wind erosion
softened and modified the mountains depending on the rocky
substratum -these gave the final features to the landscape as
we see it nowadays. The Andean slopes and valleys are humid
and rainy areas as the Patagonian mountains are quite low
-these let the Pacific humid winds pass through the valleys.
After unloading the humidity in the mountains, they move fast
and dry towards the east so the forest occupies only a narrow
band in the Andes. Beyond the mountain range, the steppe
extends in the Patagonian plateau. |
