Der Klimagang im Rheinischen Schiefergebirge und in seinem näheren und weiteren Umland zwischen dem Mitteltertiär und dem Beginn des Pleistozäns. Ein Beitrag zur Frage von Tropenklima und Mittelgebirgsmorphologie

Abstract

By using geomorphological and sedimentological data (Part II) and by comparing them with the climatic conditions as shown by tertiary flora and fauna (Part III) the author tries to arrive at a finer and perhaps revised conception of how the climate of Central Europe developed during the Tertiary. (For former and different opinions, the reader will turn to the papers by Barker, Budel and Jessen. The results seem to be as follows. A fully - or even marginally - tropical climate of an A-type appears not to have been in existence since the Middle Oligocene (or the Upper Oligocene at most). Any such climate-type must definitely have come to an end in the following tertiary periods, (at least, this is to be deduced from our material). Instead, the prevailing climatic conditions since the Middle Oligocene can be described best as subtropical or intermediate (not cold, but not too hot either, similarly neither too arid, nor too humid: see Table) with some minor oscillations. The changes from the tropical to the subtropical climates and from these to the Pleistocene ones cannot be said to consist of sharp breaks; the changes were more or less smooth. Yet the change from the tropical towards the subtropical conditions may be called a real break in a geomorphological sense, since the subtropical climate prevailed from the Middle Oligocene right to the end of the Pliocene (Part IV). The geomorphological consequence of this conclusion seems to be obvious: pene plains (strictu sensu, only those formed under tropical conditions) could not be generated actively under such an altered climate. Yet: there certainly exist flattened levels which must have been formed between the Middle Oligocene and the beginning of the Pleistocene. For these levels a different type of creative mechanism must be assumed. The results arrived at from the data of a rather limited area can be well compared with the recent findings of Mensching in the Sahara and the older ones by Mabesoone in the Duero Basin (Spain). The findings of these two authors seem to confirm our deductions - at least, they are not contradicted by them (Part V).