Chapter 1
Climatic geomorphology
1. Introduction to geomorphology
The term "geomorphology" comes from the ancient Greek words geo (Earth), morphos
(shape) and logos (thesis). This is, therefore, the science of the form of the land surface.
Several authors limit the scope of geomorphology to the study of subaerial landscapes,
whereas others also include submarine topography. Even the study of extraterrestrial
landforms has recently been included in the so-called planetary or extraterrestrial
geomorphology (Baker, 1993).
The topography of the Earth's surface is the result of the balance between endogenic
and exogenic forces. Endogenic forces trigger vertical movements that generate large
mountain belts and depressions, whereas exogenic forces work progressively to denude
the resulting relief. This permanent interplay of forces has been performed at different
scales on the Earth's surface during the whole of geological history. The external
processes occur in a classical sequence of weathering, erosion, transport and sedimentation. The result is the generation of different erosive and depositional landscapes, with
different specific features depending on the dominant process working in the different
morphogenetic environments. The energy that powers these processes comes from
different sources. Solar radiation received by the Earth heats the land surface and the
atmosphere, as it constitutes the main source of energy for meteorological processes.
Such processes control rock weathering, soil formation, relief development and also
the biological activity of plants and animals. In addition, gravitational energy supports
the processes of sediment transport and mass wasting. Finally, the internal energy of the
planet is the ultimate source of energy for virtually all tectonic processes and the
associated crustal movements that generate relief (Biidel, 1968, 1977).
Traditionally, the study of geomorphology has focused on the analysis of the sequence
and nature of geomorphic events involved in the present configuration of the Earth's
surface through geological time. This approach is denoted by some authors as historical
geomorphology (Chorley, 1978). Recently, the study of the working processes at smaller
scales, together with the analysis of the correlative landform variability, has resulted in the
so-called quantitative (Chorley, 1978) or processes geomorphology (Hart, 1986; Thorn,
1988a). As pointed out by Chorley et al. (1984) such historical studies are based on
retrodiction, whereas processes analysis is mainly focused on forecasting. Both trends are
the dominant ones in most current geomorphological studies. In some countries, processes
analysis has been stimulated in opposition to traditional studies of relief development over
long time spans. From the study of micro-landform development, however, we can obtain
valuable information for a better understanding of the long sequence of events that
has resulted in present-day landforms. We could compare this situation to that experienced
Climatic geomorphology
1. Introduction to geomorphology
The term "geomorphology" comes from the ancient Greek words geo (Earth), morphos
(shape) and logos (thesis). This is, therefore, the science of the form of the land surface.
Several authors limit the scope of geomorphology to the study of subaerial landscapes,
whereas others also include submarine topography. Even the study of extraterrestrial
landforms has recently been included in the so-called planetary or extraterrestrial
geomorphology (Baker, 1993).
The topography of the Earth's surface is the result of the balance between endogenic
and exogenic forces. Endogenic forces trigger vertical movements that generate large
mountain belts and depressions, whereas exogenic forces work progressively to denude
the resulting relief. This permanent interplay of forces has been performed at different
scales on the Earth's surface during the whole of geological history. The external
processes occur in a classical sequence of weathering, erosion, transport and sedimentation. The result is the generation of different erosive and depositional landscapes, with
different specific features depending on the dominant process working in the different
morphogenetic environments. The energy that powers these processes comes from
different sources. Solar radiation received by the Earth heats the land surface and the
atmosphere, as it constitutes the main source of energy for meteorological processes.
Such processes control rock weathering, soil formation, relief development and also
the biological activity of plants and animals. In addition, gravitational energy supports
the processes of sediment transport and mass wasting. Finally, the internal energy of the
planet is the ultimate source of energy for virtually all tectonic processes and the
associated crustal movements that generate relief (Biidel, 1968, 1977).
Traditionally, the study of geomorphology has focused on the analysis of the sequence
and nature of geomorphic events involved in the present configuration of the Earth's
surface through geological time. This approach is denoted by some authors as historical
geomorphology (Chorley, 1978). Recently, the study of the working processes at smaller
scales, together with the analysis of the correlative landform variability, has resulted in the
so-called quantitative (Chorley, 1978) or processes geomorphology (Hart, 1986; Thorn,
1988a). As pointed out by Chorley et al. (1984) such historical studies are based on
retrodiction, whereas processes analysis is mainly focused on forecasting. Both trends are
the dominant ones in most current geomorphological studies. In some countries, processes
analysis has been stimulated in opposition to traditional studies of relief development over
long time spans. From the study of micro-landform development, however, we can obtain
valuable information for a better understanding of the long sequence of events that
has resulted in present-day landforms. We could compare this situation to that experienced