Cambios en la Tierra

JUANJOSÉ ANDRÉS MOLÍAS
DYNAMIC PLANET
• The changing surface of the Earth and its
causes (Landscape changes, slow changes,
brusque change, average changes)
• Metorisation and land formation (Processes
which fragments rocks, the formation of
soils)
• The effect of the wind on landscapes (where
and how the wind acts on the landscapes,
Aeolic, transport and sedimentation)
1-LANDSCAPE CHANGES
The landscape that surrounds us has not always looked like it does today. Leaving aside the changes
made by human beings (constructions, dams, bridges…), the land relief changes as result of natural
processes. In some places the mountains have appeared, in others, the mountains have became hills.
There are even mountain areas which were in the past, plains beneath the sea, this is why, in this places
we can can find fosils of marine life.
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The changes in land relief may occur rapidly or very slowly.
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2-SLOW AND BRUSQUE CHANGES
Slow changes to the Earth’s are caused by the activity of our planet and occur over a long period of time,
sometimes millions of years. Is practically impossible to see them unless we are able to measure some of the
changes with very sensitive instruments.
Brusque changes to the Earth’s surface are also caused by the internal avtivityof the planet but they happen
very quickly and sometimes with catastrophic consequences. Two examples are:
-An earthquake is a brusque movement of the Earth¡s crust. Altough it only lasts for a few seconds it can have
sufficient force to destroy whole cities and to transform the landscape.
-A volcanic eruption is the brusque expulsion of materials from a volcano. Volcanoes can cause catastrophes and
modify the landscape by depositing the material they expel.
4-AVERAGE CHANGES
There are other changes whcih occur at an average speed, progressively and they take place over centuries,
thousands or millions of years. These kind of changes are due to the action of the atmosphere and the hydrosphere
on the planet. There are three factors which are common to all these action: ersion, transport and sedimentation.
-Erosion is the tearing off of fragments of rocks produced by the the action of different agents: water, wind, ice…
Predominates in the high course of a river.
-Transport is the desplacement of these fragments from one place to another. It is normally due to the action of the
same agent which brought about the erosion. Predominates on the middle course of a river.
-Sedimentation is the depositing of the materials that have been carried by the different agents. This occur when
the force of the transporting agent decreases. Predominates on the low course of a river
Altough it seems very strange this
rock havent been paint this colours
are naturals.
Erosion in a rock which can be
caused y the wind or by the
rain.
One of the most famous erosion in
Cuenca (ciudad encantada)
IGNEOUS
SEDIMENTARY
METAMORPHIC
IGNEOUS ROCKS:
SEDIMENTARY ROCKS:
METAMORPHIC ROCKS:
AEOLIC EROSION:
Is that which is produced by the impact of the wind on rocky materials. Wind, alone, has a
very small power of erosion, however if it carries sand. Its capicity for erosion is
considerably increased.
AEOLIC TRANSPORT:
Is not very intensive. The wind can only carry small particles of rock, sand and gravel. In
deserts we can see stony fields or regs which are briught about by the transporting action
of the wind.
AEOLIC SEDIMENTATION:
Takes place when the wind drops or when it hits irregularity in the landscape. The sun
carried by the wind from other areas accumulates to form dunes
WITH THE COLABORATION OF:
Juanjosé Andrés Molías
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