»	Landmarks in the History of Science » Geoscience » 1st Edition, 1912, [The Origin of Continents] / Die Entstehung der Kontinente [The Continental Drift Theory]

1st Edition, 1912, [The Origin of Continents] / Die Entstehung der Kontinente [The Continental Drift Theory]

Autor: Alfred Wegener

Cod: 6518
In stoc: Nu

48000.00Lei

Detalii produs
1st Edition of this revolutionary work published by Justus Perthes, Gotha, 1912.
Alfred Wegener may be considered the Newton of geophysical researches.

''One hundred years ago, in the German city of Frankfurt, a young man who at Marburg University worked as a physicist and meteorologist told a meeting of the recently founded Geologische Vereinigung (GV) how the Earth functions. He shocked the meeting of eminent geologists with an outrageous idea – that since the Late Palaeozoic the continents and oceans were not fixed - and that they had once been grouped together in one vast supercontinent, Pangaea, and one even larger ocean. The continent had fragmented and the fragments drifted apart, five modern oceans forming between them.

Alfred Wegener and his ideas were not welcomed and his ideas were rejected furiously by most geologists. However, he was convinced that his unorthodox interpretation explained a wealth of many puzzling observations better than other theories - and in a manner that definitely called for further tests. In the same year, 1912, his ideas were published in an important geographical journal, Peterman’s Geographische Mitteilungen (PGM).

Wegener wrote: 'Such a large number of surprising simplifications and interrelationships become visible after only a preliminary scanning of the main geological and geophysical results, and for that reason alone I consider it justified, even necessary, to replace the old hypothesis of sunken continents by the new one, because it appears to be more successful. The old hypothesis [land bridges] has been demonstrated inadequate by its antithesis of the permanence of the oceans. In spite of its broad foundation I call the new idea a working hypothesis and I wish it to be taken as such, at least until it has been possible to prove by astronomical positioning with undoubtable accuracy that the horizontal displacements continue to the present day.'

Wegener thought a lot about the mechanism of drift. However, his priority in ‘PGM12’ was to describe the phenomenon. Explanations could wait. After discussing isostasy and plasticity at length and describing geosynclines in a quite modern way (as an isostatic response to sediment loading of continental margins) Wegener wrote: '…what forces cause horizontal drift, is an obvious question … but premature. It is first … necessary to exactly realise the reality and nature of the movements before we can hope to understand their causes.” He discussed polar wander, and thought of it as a consequence, not a cause, of mass-changing redistribution related to drift. He considered tidal forces a more likely cause. “Possibly for the time being, it is best to consider continental drift the consequence of accidental currents inside Earth. Hopefully it will be possible in the future to separate the accidental aspects from the tendency toward equilibrium in rotation.'

Interestingly, at first Wegener envisioned a phenomenon akin to ‘seafloor spreading’. In ‘PGM12’ this idea is expressed twice, most significantly on page 305: '… we now seem able to explain the different ocean depths.

Since for large areas we will have to assume isostatic compensation of the seafloor, the difference means that the seafloor we believe to be old is also denser than that believed to be young. Moreover, it seems undeniable that freshly exposed sima … will for a long time maintain … higher temperatures (perhaps 100°C in the uppermost 100km on average) than old, largely cooled seafloor. … The depth variation appears also to suggest that the Mid-Atlantic Ridge should be regarded as the zone in which the floor of the Atlantic, as it keeps spreading, is continuously tearing open and making space for fresh, relatively fluid and hot sima from depth.'

Strong opposition from geologists and (especially) geophysicists persisted for decades worldwide, especially in Germany and America, even into the 1960s.''

Wolfgang R. Jacobi, 100 years of mobilism, Geoscientist, 22.09 October, 2012

Die Entstehung der Kontinente in Dr. A. Petermanns Mitteilungen aus Justus Perthes'
Geographischer Anstalt, 58 Jahrgang, 1912, 1 Halbband, Gotha, Justus Perthes, 1st Ed.
pp. 185-195; 253-256; 305-309; 7 figs. in text and 1 plate with 3 figs. outside the text.

Vol. 58/1, 1912; 8vo; p. xvi, 344, 56 plates outside the text (many beautiful colored maps
included), ex-libr. bound copy, hardback, small stamp on title page, signs of age, clean text.

Price: $ 12,000.00