Climatic geomorphology
5
works were transmitted to Spain from the Middle East by means of the Arabs. The Arab
manuscripts were translated into Hebrew and Latin in the ancient Translators School of
Toledo (Cailleux, 1961). Therefore, during this time the diffusion of knowledge was
mainly carried out in the monasteries, but also in some cases by means of the individual
patronage of a few kings. In this fashion, Avicena (Ibn Sina, 980-1037), an expert on
Aristotle's work, developed hypotheses on the desert landscapes of Arabia. He thought
that mountains could be generated by elevation of the ground or by the work of water and
wind (Thornbury, 1954).
This period is also characterized by catastrophist or cataclysmic ideas partly based upon
Christian thinking, with the pervasive use of Noah's Flood for the explanation of many
natural processes or observations. This dogmatism produced absurd proclamations, such
as the one manifested in 1654 AD by Archbishop Ussher of Ireland, which stated that the
Sky and the Earth, centre and circumference, were created together by the Holy Trinity on
October 26 of 4004 BC, at 9 o'clock in the morning (King, 1976a,b).
Catastrophist ideas dominated until the 19th century. But meanwhile the brilliant
Leonardo da Vinci (1452-1519) exposed in his works significant considerations on the
origin of the mountains (pioneering ideas about isostasy). He also indicated that rock salt
was generated from the evaporation of seawater, as well as considering the importance of
fluvial erosion and the generally slow work of geomorphic processes. Unfortunately his
ideas were not published until the end of the 18th century, and his scientific influence
during his epoch was practically nil (Ellenberger, 1988). Catastrophism consequently was
the prevailing doctrine during this period.
During the 17th, 18th and part of the 19th centuries, the most significant advances in
geomorphology came mainly from the studies on applied hydrology, carried out by several
engineers. These were mainly French engineers, such as Perrault, De Chezy, Surrell,
Guetthard, Desmarest and others who discarded in their works many academic concepts
that were mostly inoperative.
Catastrophist theories had their opposite counterpart in the uniformitarian ideas
developed at the end of the 18th century, with the postulation of the principle of actualism.
Although previously noted by others in obscure works, this principle was first developed
by Hutton (in 1726-1797) in his work Theory of the Earth (in Hutton, 1788) and later
popularized by Lyell (in 1797-1875) in the first edition of Principles of Geology
(Lyell, 1830), which was extensively reedited and reprinted. These Scottish geologists
established the basis of modem geology, as well as geomorphologic methods. Uniformitarian theory can be synthesized in the simple sentence: "the present is the key to the
past." This means that different landforms have been created by processes similar to those
of the present day, but operating over long periods of time. As we can see, it is totally
contrary to the ideas of catastrophism. For example, Lyell described mountains that were
eroded by weathering and fluvial transport, and later the transported materials were
deposited in sedimentary basins which would ultimately give rise to new mountains.
During this period Playfair (in 1802) published his work Illustrations of the Huttonian
Theory of the Earth, establishing that in areas of homogeneous lithology and structure that
are subject to fluvial erosion, the valleys are proportional to the size of the tributaries
contained in them. It is today is known as "Playfair's Law."
But the catastrophists, as with the cleric geologists Buckland and Sedgwick, argued that
the erratics of glaciers and the alpine hanging valleys could only be explained by
5
works were transmitted to Spain from the Middle East by means of the Arabs. The Arab
manuscripts were translated into Hebrew and Latin in the ancient Translators School of
Toledo (Cailleux, 1961). Therefore, during this time the diffusion of knowledge was
mainly carried out in the monasteries, but also in some cases by means of the individual
patronage of a few kings. In this fashion, Avicena (Ibn Sina, 980-1037), an expert on
Aristotle's work, developed hypotheses on the desert landscapes of Arabia. He thought
that mountains could be generated by elevation of the ground or by the work of water and
wind (Thornbury, 1954).
This period is also characterized by catastrophist or cataclysmic ideas partly based upon
Christian thinking, with the pervasive use of Noah's Flood for the explanation of many
natural processes or observations. This dogmatism produced absurd proclamations, such
as the one manifested in 1654 AD by Archbishop Ussher of Ireland, which stated that the
Sky and the Earth, centre and circumference, were created together by the Holy Trinity on
October 26 of 4004 BC, at 9 o'clock in the morning (King, 1976a,b).
Catastrophist ideas dominated until the 19th century. But meanwhile the brilliant
Leonardo da Vinci (1452-1519) exposed in his works significant considerations on the
origin of the mountains (pioneering ideas about isostasy). He also indicated that rock salt
was generated from the evaporation of seawater, as well as considering the importance of
fluvial erosion and the generally slow work of geomorphic processes. Unfortunately his
ideas were not published until the end of the 18th century, and his scientific influence
during his epoch was practically nil (Ellenberger, 1988). Catastrophism consequently was
the prevailing doctrine during this period.
During the 17th, 18th and part of the 19th centuries, the most significant advances in
geomorphology came mainly from the studies on applied hydrology, carried out by several
engineers. These were mainly French engineers, such as Perrault, De Chezy, Surrell,
Guetthard, Desmarest and others who discarded in their works many academic concepts
that were mostly inoperative.
Catastrophist theories had their opposite counterpart in the uniformitarian ideas
developed at the end of the 18th century, with the postulation of the principle of actualism.
Although previously noted by others in obscure works, this principle was first developed
by Hutton (in 1726-1797) in his work Theory of the Earth (in Hutton, 1788) and later
popularized by Lyell (in 1797-1875) in the first edition of Principles of Geology
(Lyell, 1830), which was extensively reedited and reprinted. These Scottish geologists
established the basis of modem geology, as well as geomorphologic methods. Uniformitarian theory can be synthesized in the simple sentence: "the present is the key to the
past." This means that different landforms have been created by processes similar to those
of the present day, but operating over long periods of time. As we can see, it is totally
contrary to the ideas of catastrophism. For example, Lyell described mountains that were
eroded by weathering and fluvial transport, and later the transported materials were
deposited in sedimentary basins which would ultimately give rise to new mountains.
During this period Playfair (in 1802) published his work Illustrations of the Huttonian
Theory of the Earth, establishing that in areas of homogeneous lithology and structure that
are subject to fluvial erosion, the valleys are proportional to the size of the tributaries
contained in them. It is today is known as "Playfair's Law."
But the catastrophists, as with the cleric geologists Buckland and Sedgwick, argued that
the erratics of glaciers and the alpine hanging valleys could only be explained by