Walker - 1967 - A geography of Italy

THE ALPS
Strewn with debris, its precipitous sides edged with aprons o f scree resting precariously
on narrow terraces (Sella group, Cima di Groste, Monte Sciliaro).
Where the dolomite has been severely fractured during the orogenesis it responds
to erosion by taking the form of towers, bastions and piimacles emerging
from massive screes (Gruppo delle Pale, Sassolungo, Cima Brenta). A few small
glaciers survive, the biggest o f them on the northern face o f Marmolada, and the
origin o f the irregular spreads o f drift on the plateaus and o f the cirques and U -
valleys o f the higher massifs is immistakable, but on the whole the rôle o f
MT.NAMBINO
2676m.
CAMPO CARLO MAGNO
MT SPINALE
SHOULDER
CIMA BRENTA
3150m,
Fig. 23. Block diagram of the Madonna di Campigho area illustrating the contrasting
morphologies of the Brenta and Adamello groups
glaciation in the morphology o f the Dolomites has been a secondary one compared
with that o f the structure and the lithology. This is well illustrated on
either side o f the Campiglio valley along which a fault has brought the crystalline
rocks of the Adamello group face to face with the dolomites o f the Brenta group.
Both areas were glaciated (and in both small glaciers persist) and yet in the
homogeneous crystalline zone to the west the sharp arêtes, lake-filled cirques
and hanging valleys o f M . Nambino and M. Ritorto illustrate the classic glaciated
landscape, while in the Brenta group the structure and lithology assert their
dominance in the form o f a succession o f shelves crowned by the bastions o f Cima
Brenta, Torre di Brenta and Cima Tosa (fig. 23 and pi. iib).
Even in the Dolomites the proportion o f true dolomite among the calcareous
rocks is quite modest; in the rest o f the high calcareous zone, notably to the
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