Geography Reference
In-Depth Information
3
TECTONICS, WEATHERING,
EROSION AND SOILS
On a large scale the landscape and oceans change slowly through
time, mainly through tectonic processes, weathering and erosion.
These slow processes also bring sudden change and hazards associ-
ated with them. Movements in the Earth's plates result in sudden
earthquakes or volcanic eruptions. Landslides are local hazards but
are natural processes of change and therefore need to be under-
stood within this context. Humans also modify the environment
and can enhance hazardous risks of rapid movements of soils and
rocks.
This chapter is the first of two that study the
geomorphology
of the Earth (i.e. processes and patterns that shape the landscape)
and which examine slow, intermediate and fast processes of land-
scape change. In this chapter we start by covering tectonic proc-
esses which build and destroy landscapes on a large scale. The
chapter then focuses on weathering and erosion which may seem
small-scale but can produce an overall effect which is global. While
weathering, erosion and deposition can also build landscapes (e.g.
sand dunes at the coast or in deserts), the overall effect on the con-
tinents in total is that tectonic processes build landscapes and
weathering and erosion including the action of rivers, glaciers and
ice sheets (which are dealt with in Chapter 4), sculpt and can ulti-
mately destroy landscapes. The environment that we see today rep-
resents one point in the overall evolution of the landscape which
changes through time. The chapter has a specific section on soils,
which are vital to our lives. Soils are a product of weathering and
biological inputs and they slowly accumulate through time. Soils
are also subject to further weathering and erosion as part of the
