Report on a structural and sedimentological analysis in the Uranium province of the Orobic Alps, Italy

Detailed structural and sedimentological studies have been conducted in 2 areas near the Val Vedello uranium mine in N Italy. These studies indicate that both the Variscan basement and the Permian cover rocks were thrust S during the Alpine orogeny. Variscan mylonitic zones were rejuvenated during the Alpine orogeny and became fault boundaries for the Permo-Triassic basins. Alpine faults also are related to contemporaneous E-W folds and these faults have displaced Permo-Triassic uranium deposits. Uranium mineralisation is attributed to a Late Permian to Triassic geothermal event which leached uranium from Permian ignimbrites and transported it along Permo-Triassic faults. Detailed mapping indicates that the host sediments formed in an arid, closed basin characterised by alluvial fans and perennial saline lakes.-from Authors