In contrast to the ongoing claims which books should be burned: what an astonishing thing a book is, binding together distant epochs, books break the shackles of time.
During the European Middle Ages the classic knowledge regarding earth was mostly stored inside books in libraries of monasteries or applied to concrete problems in engineering and mining, there was little interest to do research or think about general principles or rules applied to earth.
In contrast in the Muslim sphere the tradition of naturalistic philosophers, resembling the scholars of classic Greek period, continued.
During the European Middle Ages the classic knowledge regarding earth was mostly stored inside books in libraries of monasteries or applied to concrete problems in engineering and mining, there was little interest to do research or think about general principles or rules applied to earth.
In contrast in the Muslim sphere the tradition of naturalistic philosophers, resembling the scholars of classic Greek period, continued.
The 'Brothers of Purity' a sect of Shia scholars located in Basra and surrounding areas, between 941 and 982 produced several written volumes, known as "The Treatises of the Brothers of Purity" in which they reassumed their knowledge of natural processes.
Regarding geology, the circle of rock formation and erosion is clearly stated, and the great amount of time necessary for these changes indicated.
''And know ye brethren, that all valleys and rivers begin from mountains and hills, run in their courses and finally flow to the seas, swamps, and lakes…Then the mountains will break and disintegrate, particularly during storms, becoming boulders, pebbles, and sands. The rain torrents will bring these pebbles and sands to the bottoms of valleys and rivers and carry them to the seas, lakes, and swamps. The sea, because of its strong waves and great turbulence, will distribute these sands, muds, and pebbles along its bottom, layer upon layer, through the passage of time and ages. These will accumulate one above the other and harden, and then mountains and hills will rise from the bottom of the sea…And know ye my brethren that when the sea becomes closed because of these mountains and hills which we mentioned originating on their bottom, the water rises and extends over the coasts to the prairies and open land which are thus covered by water. This will go on through the passage of time, until the place of the prairies becomes the site of the sea, and the place of the sea becomes land.''
(from FISCHER et al. 2010).
Fig.1. Image of Ibn Sina, medieval manuscript entitled "Subtilties of Truth", 1271 (image from Wikipedia).
These ideas doubtless inspired the great Islamic scholar Abu- Ali- al-Husayn ibn Abdulla-h Ibn Sina (981 to 1037), in the western world known for his contribution in the field of medicine under the Latinized name Avicenna.
In his opus magnus "Kitab AI-Shifa" - the Book of Cure from Ignorance, he gives an introduction in the fields of stratigraphy, hydrology, mineralogy and seismology:
"We shall begin by establishing the condition of the formation of mountains and the opinions that must be known upon this subject. the first [topic] is the condition of the formation of stone, the second is the condition of the formation of stone great in bulk or in number, and the third is the condition of the formation of cliffs and heights."
(from AL-RAWI 2002).
Regarding the specific process of the formation of rocks, which then build up the mountains, he states a process that resembles the formation of flowstone from running water:
"In general, stone is formed in two ways only (a) through the hardening of clay, and (b) by the congelation of waters...[] Stone has formed from flowing water in two ways (a) by the congelation of water as it falls drop by drop or as a whole during its flow, and (b) by the deposition from it, in its course, of something which adheres to the surface of its bed and (then) petrifies. Running waters have been observed, part of which, dripping upon a certain spot, solidifies into stone or pebbles of various colours, and dripping water has been seen which, though not congealing normally, yet immediately petrifies when it falls upon stony ground near its channel...[] Stones are formed, then, either by the hardening of agglutinative clay in the sun, or by the coagulation of aquosity by a dessicative earthy quality, or by reason of a desiccation through heat."
(from AL-RAWI 2002).
Fig.2. Example of layered flowstone from the Eemian- and possibly Holstein interglacial in the Conturines Cave (Dolomites).
Avicenna also clearly recognized fossils as ''petrifications of the bodies of plants and animals'' and implies that in the past there were major changes sculpturing the surface of earth.
"If what is said concerning the petrifaction of animals and plants is true, the cause of this phenomenon is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquakes and subsidence, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters..."
Fig.3. Example of Holocene travertine from a quarry near the village of Pollingen (Bavaria), with enclosed shell of a snail.
''It is also possible that the bed of the sea may have been originally in the shape of plains and mountains, and that when the waters ebbed away, they were exposed. It may be noticed that some mountains are in layers, and this may be because each layer was formed at a different period.''
"It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that some mountains appear to have been piled up layer by layer, and it is therefore likely that the clay from which they were formed was itself at one time arranged in layers. One layer was formed first, then at a different period, a further layer was formed and piled upon the first, and so on...[] Such is the formation of mountains."
"The formation of heights is brought about by (a) an essential cause and (b) an accidental cause. The essential cause (is concerned) when, as many violent earthquakes, the wind which produces the earthquake raises a part of the ground and a height is suddenly formed, In the case of the accidental cause, certain parts of the ground become hollowed out while others do not, by the erosive action of wind and floods which carry away one part of the earth but not another...[]... Their elevation is due the excavating action of floods and winds on the matter which lies between them, for if you examine the majority of mountains, you will see that the hollows between them have been caused by floods. This action, howver, took place and was completed only in the course of many ages, so that the trace of each individual flood has not been left; only that of the most recent of them can be seen."
(from AL-RAWI 2002).
Bibliography:
FISCHER, A.G. & GARRISON, R.E. (2009): The role of the Mediterranean region in the development of sedimentary geology: a historical overview. Sedimentology 56: 3-41
AL-RAWI, M.M. (2002): The contribution of Ibn Sina (Avicenna) to the development of Earth Sciences. Foundation for Science, Technology and Civilisation. 4039: 12
Online Resources:
Wikipedia: Avicenna (Accessed 19.09.2010)
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