What do you mean by the term Primarrumpf ?

The Walther Penck German geomorphologist introduced several terms in geomorphology, which could be independent of the cycle concept of W.M. Davis. The term Primarrumpf as the word indicates refers to a primary level surface, which is marked by slow imperceptible but accelerating uplift and occurs in the initial stages of its geomorphic history.

Now this initial or primary surface might be a newly emergent (from below the sea) surface. Alternatively it might be a peneplain (fastebene or endrumpf in German terminology) truncating different structures. In either case, it becomes a primary or new surface because of uplift, which is extremely showed accelerating and long continued. Such uplift leads to the production of convex slopes.

Primarrumpf is similar to what Davis described as ‘an old-form-birth peneplain’, in areas where uplift was slow and not rapid, as he thought normally to be the case. Walther Penck’s use of Primarrumpf and other relevant terms was to avoid the cycle concept of Davis. He did not recognize that there was rapid uplift in the beginning causing all the elevation and that then followed a long period of still stand during which the initially high surface was subject to sequential forms of the stages called young; mature and old by Davis. Penck emphasized that geomorphic forms were not a function of structure, process and stage but an interaction between the rate and type of uplift and other factors in which structure may not be significant. This is in marked contrast with Davis’s assumption of still stand without uplift over most of the period.

As primarrumpf is an extremely tame surface in the beginning, it remains so for a long time because the insignificant degradation is matched by slow uplift.

Carl Sauer was a supporter of Penck and thought that some parts of the Peninsular Range of California were probably primarrumpf type surface.

Some like Sauer, Boswell and Czech gave the name primary peneplain or peneplane to primarrumpf. It could be distinguished from a peneplain in the sense that while the former was very near the base level, a primarrumpf was quite above it. Again, the slopes in a peneplain would decrease with further advance of time. In case of primarrumpf it would increase. Whereas peneplains have residuals like monadnocks, primarrumpfs have none. If it is difficult to point out actual examples of peneplains it is more difficult to indicate primarrumpf in the field.

The term, however, may be retained as one broadening the perspective of erosion surfaces. “Penck appears to have had in mind such features as the revived and stripped peneplains.