publications.ffspeleo.fr [Bulletins]

The “piani" in the Venetian Prealpes and the High Apennines have been exclusively formed by corrosive karst processes and a co-operation of tectonics - basining and faulting - cannot be proved. In fact the karst processes were preceded by phases of fluviatile planation or dissection, which, in turn, cut anterior tectonic structures, which had created zones of especial favour for the sub sequent karst processes. Such zones are especially the boundaries between two rocks of different liability to karstification, whereas the faultlines influenced more the preceding relief created by planation and dissection. The only thing possible, therefore, is to speak of a certain "accordance" of karst depressions to pre-existing tectonic structures, in the main due to differences in lithology. The karst depressions grow at the expense of the rocks more liable to karstification, also where their formation commences at fluviatilly modelled fault-lines. The karst depressions are not prior to the Middle Pliocene. It is not possible to comment in detail upon the nature of the preceding planation processes, the younger phases of which are still partly recognizable as marginal terraces in some depressions. They are likely to be of fluviatile origin, and developed near the baselevel of erosion. In the Apennines and the Venetian Prealpes these planation processes date back to the Pontien, without, however, having been capable of forming a peneplain...
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