Wednesday, August 11, 2010

History of Geology

Already in ancient times, people have long possessed a working knowledge of the search for mineral resources, the dismantling and recycling. The first attempts at a theoretical treatment of geological problems, such as the cause of earthquakes, or the origin of fossils, however, found only in the Ionian natural philosophy in the fifth Century v.C. Until the early modern era was the doctrine of the four elements of Empedocles and Aristotle's doctrine of the transmutation of the elements also indicative of the ideas about the nature of metals, minerals and rocks.

While the decline of the Roman Empire in Late Antiquity, these views were only in the Eastern, Greek dominated part handed down, where it in the early Middle Ages by Arab scholars, like Ibn Sina were resumed. In Western Europe, however, even were a lot of practical knowledge in the mining industry lost. Only in the 12th and 13 Century Western alchemists began again with the formation of metals and rocks inside the earth to deal. During the Renaissance such speculation, not only by humanist scholars such as Paracelsus were expanded, but also extensive empirical data and practical methods supplemented, especially by Georgius Agricola. From such approaches developed until the 17th Century, a kind of "proto-geology", which had much in common with "proto-chemistry" of economists, alchemists and mining engineer Johann Joachim Becher.

An important step in establishing an independent science of geology was the Danish scientist Nicolaus Steno, by introducing in 1669 the stratigraphic principle. With this he established the principle that the physical storage of sediment layers in reality a time sequence of rock deposits in turn corresponds. Even Robert Hooke speculated about the same time, if not from the fossil content of rocks could reconstruct the historical process of rock formation.

In the Age of Enlightenment, tried mine managers and engineers increasingly a theoretical understanding of geological contexts. Here they developed since the mid-18th Century, the basic methods of geological mapping and the creation of stratigraphic profiles.

The beginning of modern geology as a science is usually recognized at the controversy between the mindsets of plutonism and Neptunism. As founder of plutonism is James Hutton (1726-97) with his postulate, all rocks are of volcanic origin. Hutton also popularized the idea that the Earth is many orders of magnitude longer than human history. The Neptunists were by Abraham Gottlob Werner (1749-1817 run), with the now discarded the basic assumption that all rocks are deposits of a primordial primeval oceans. The combination of magmatism, sedimentation and rock alteration developed in the following, the notion of the cycle of rocks.

To William Smith in 1817 established the use of index fossil for the relative dating of rock layers within a stratigraphic sequence.

At about the time from 1830 to 1850 the dispute was between catastrophism in the wake of Georges de Cuvier (1769-1832) and Sir Charles Lyell to actualism (1797-1875), the second major controversy in the history of geology. While the catastrophists of sudden and global upheaval in the earth went out, followed by recreation of the extinct creatures that actualistic the uniform and steady development of the earth stressed in numerous small steps, which accumulate over long periods of time gradually (gradualism). Even Charles Darwin (1809 -1882) was followed in his theory of evolution, with its slow development of new biological species, largely the actualistic principle.

As a result, the geologists involved more with the problems of mountain building and global movements of the earth's crust. Well into the 20th Century, dominated on Léonce Élie de Beaumont (1798-1874) declining idea that the global mountain belt are the result of cooling and shrinking of the globe. From the observation of folded and tectonically disturbed rocks developed James Dwight Dana (1813-1895) to 1875, the geosyncline theory. This tectonic model of explanation was Eduard Suess (1831-1914) and Hans silence (1876-1966) significantly developed.

Here, the geotectonic hypotheses were dominated by the principle of Fixismus. The position of the continents and oceans was regarded one another as largely immutable. Lateral movements of the earth's crust, the traces could be observed in fold mountains or in regional gap systems were considered to be largely local issues. On the other hand were vertical movements of the earth's crust as crucial for the reduction of ocean basins, or the rise of land bridges between continents.

The first important ideas about the possibility of significant horizontal movements of land masses, are found in the continental drift hypothesis Alfred Wegener (1880 - 1930) from the year 1915. The breakthrough of Mobilismus but was only three decades later, as a fundamentally new observations of geophysics and oceanography to the development of the now generally accepted theory of plate tectonics resulted.


See Also: Sending Flowers, Online Florist, Florist

No comments:

Post a Comment