Geography Reference
In-Depth Information
There were detailed descriptions of the different types of physical
landscapes found on the Earth's surface, but there were also many
theories and models. The idea of a 'cycle of erosion', suggesting
that landscapes progressed through stages of youth, maturity, and
old age, was one of the earlier models. At a smaller scale, there
were theories for the formation of tors in granite areas and for the
plethora of strange landforms found in deserts. Climatology offers
another good example where careful recording of key indicators,
such as temperature and precipitation, allowed the division of
the world into climatic zones that could eventually be understood
in terms of the general circulation of the atmosphere, synoptic
climatology, and weather systems.
Both traditional and new roles for fi eldwork in physical geography
can be demonstrated by the example of reconstructing Quaternary
environmental change at a site on the northern coast of Mallorca
in the western Mediterranean. Erosion of the coastal cliffs at
Cala d'es Cans has exposed a section through a fan of deposits
accumulated at the mouth of the Torrente d'es Coco, which drains
a relatively small catchment in mountainous terrain (Figure 21).
This example is indicative of the type of fi eld recording that is
necessary to reconstruct the sequence of events through which
the landscape has passed. The fi eld study was supplemented by
several types of laboratory analyses on samples of sediments and
shells; the former including Optically Stimulated Luminescence
(OSL) dating, which established the timescale.
The various layers in the section refl ect changing processes and
fl uctuations in climate. Around 140,000 years ago the area was
in an interglacial, or interval between signifi cant glaciations,
experiencing environmental conditions that were a little warmer
than in the present interglacial (the Holocene). At that time, the
fi rst sediment to be deposited was an aeolian (wind-deposited)
sand, which later became cemented to form an aeolianite in which
sand-dune bedding can be seen. Above this in the section is a
sequence of layers produced under generally cooler but fl uctuating
