Truncated uplands

A truncated upland, truncated highland or bevelled upland (German: Rumpfgebirge) is the heavily eroded remains of a fold mountain range, often from an early period in earth history. The term Rumpfgebirge ("rump mountains") was first introduced into the literature in 1886 by Ferdinand von Richthofen. The rumps of the former mountain ranges may be found in many lowland regions of the earth's crust (where they form the so-called basement rocks) and especially outcrop in Central Europe through more recent tectonics. This could result in an uplifted peneplain which is one type of truncated upland.

The valley structures of truncated uplands are often more irregular than in the younger fold mountains, which is due to the considerably younger tectonic processes and stronger erosion of the former mountain ranges that were originally often up to several thousand metres high. By contrast, their plateaux are orographically similar in shape.

In western Europe many of the Central Upland ranges fall into the category of truncated uplands - for example the Harz, the Ore Mountains, the Fichtel Mountains and the Rhenish Massif. Other ranges also date to the time of the Variscan orogeny, including those on either side of the Rhine, such as the Black Forest and Vosges and, from the Bavarian Forest in northeast Bavaria, through the Bohemian Forest in the Czech Republic to the Bohemian Massif in Austria and the Czech Republic, not to mention the French Massif Central. This mountain formation took place in the Middle Palaeozoic, during the Devonian and Carboniferous epochs about 350 to 250 million years ago. Already by the Permian the Variscan mountains had been eroded into the so-called Permian peneplain and overlain by sedimentary strata. These remains survive as Variscan "islands" between the younger sedimentary rocks of the Mesozoic. During the course of subsequent earth history, fault block tectonics followed, which characterised the present appearance of the German Central Uplands. These truncated Variscan mountains are usually strongly affected by magmatic processes.

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