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| Rock Decay |
Rock Decay:
Abha’s weather is changing from
being hot to cold but mostly cold , therefore weathering consequences can occur.
Many processes shape earth’s surface, one of the important processes is
weathering. It is the beginning of changing the earth’s surface, and it occurs
over, relatively, large periods of time. It is important to understand the
difference between weathering and erosion. Weathering is rock decay, while
erosion is the process of transporting weathered material. Weathering and
similar processes are studied in the field of geomorphology, which is a
combination between both Geography and Geology.
Weathering:
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| Chemical Decay |
There are two
different types of weathering. The first type is physical weathering, which can
happen in many forms. Physical weathering takes advantage of physical
weaknesses in a rock, and increases their numbers. For example, frost decay is
one of the important physical weathering processes. It happens more prevalently
in high altitudes and latitudes where many freeze-thaw cycles happen. It
happens when water seeps into joints, freezes, thermally expands, and melts
back. This happens over large periods of time, and after a sufficient number of
cycles, blocks of rocks will be pushed away. The second type is chemical decay
is the chemical alteration of rocks and minerals. One of the most important
chemical decay processes is dissolution. In this process, a mineral is completely
dissolved by water. This causes many constructional problems. Sink holes happen
when limestone dissolves by groundwater, which makes it important for people to
study the layers underneath where they want to build.
Mass Wasting:
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| Mass Wasting |
Since Abha is above
the sea level, it is surrounded by mountains. Mass wasting depends primarily on
gravity to transport decayed material down slopes. The material that is being
transported is called colluvium. It is important to understand mass wasting in
order to mitigate its hazards. Many people lose their houses due to mass
wasting. Mass wasting can happen in many forms. Rocks can fall, slide, topple,
or flow.
