The wind worn pebbles (ventifacts) found in the lowermost beds of the Prato Solaro Mb., on the type-section and elsewhere in Orobic Alps, evoke those recorded in the Early Triassic from many other places of Germany, England, France, Spain, Sardinia and Bulgaria.
In this context, the maximum of aridity is recorded by wind-worn quartz pebbles (ventifacts) present in the basal beds of the Servino Formation of the Orobic Alps.
Quartz is locally present as marginally knappable blocks of irregular crystal size, found in bedrock outcrops along the shores of the lake, and as ventifacted cobbles at the base of the soil profile.
However, the presence of many large schist and quartz feature stones in C1 indicates that at least some sources of bedrock were available nearby during the earlier occupation, and the low presence of smooth cortex on quartz debitage in both components indicates procurement from eroded bedrock exposures rather than smaller, weathered ventifacts.
In summary, we consider the hypothesis that ventifacts
should necessarily occur in a single interval during the Early Triassic, as proposed by Cassinis et al.
In spite of this, because of explaining the presence in the underlying Prato Solaro Member of ventifacts potentially spanning from Griesbachian to Smithian but generally related to the latter times, we felt constrained to invoke that this stratigraphic problem still deserves further study in central Lombardy (Cassinis et al., 2007, p.
in their reply, the ventifacts found in the lowermost beds of the Prato Solaro Member could have originated from this dry climatic regime.
The vast majority of the pebbles are well rounded by long fluvial transport, but many display secondary ridges and facets shaped by wind-blown sand (ventifacts).
As redefined above, its basal unit (Chequilla Conglomerate Member) is composed of conglomerates yielding ventifacts (Durand, in Arche and Lopez-Gomez, 2005).
Cassinis et al (2003) have observed scarcely reworked and even in situ ventifacts (paleoreg) in this formation, as well as an eolian dune remnant.
The Triassic succession here also seems to begin with basal conglomerates, which contain many ventifacts at several localities.
In this context, we can readily explain the presence of aeolian features (dunes or ventifacts) at a large scale.