In the past decade the presence of a generally transcurrent tectonic regime in Europe at the end of the Hercynian collision has been emphasized. The Permo-Carboniferous rocks of the continental domains, including a number of sedimentary basins infilled with alluvial-to-lacustrine and volcanic deposits, were especially affected by that dynamic regime. For Spain, France, Germany, Italy, and other European regions the presence of transtensional and transpressional conditions is almost unanimously accepted, as such a regime can explain the larger part of the structural features generated during the late Hercynian interval. That activity lasted from the late Carboniferous until the Permian and perhaps more recent times.

In the Southern Alps, however, examples of such transcurrent tectonics have not been well documented. This chapter, which deals with late Palaeozoic transtensional activities in eastern Lombardy, western Trentino, and the Carnic Alps, is an early contribution to those topics (Figure 5.1). The former area was investigated by G. Cassinis and C. R. Perotti, and the latter was examined by C. Venturini.

Central Southern Alps

The Permian period in the central Southern Alps can be divided into two main tectonosedimentary cycles. Those two cycles were separated by a marked hiatus that has recently been dated to the early part of the late Permian (Italian I.G.C.P. 203 group, 1986; Cassinis and Doubinger 1991, 1992) (Figure 5.2).

The upper cycle, or cycle 2, is characterized by the Upper Permian Verrucano Lombardo–Val Gardena Sandstone, red fluvial deposits at the base of which lithologically different sandy-ruditic bodies crop out locally.