New dates of a Northern Italian loess deposit (Monte Orfano, Southern pre-Alps, Brescia)

Loess in Northern Italy has been usually considered deposited during the MIS 4-2 period, which corresponds to the last Pleistocene glacial cycle. In particular, no absolute dating evidenced loess depositions older than ca. 89 ka. We investigated two strongly rubified soil profiles in the southern margin of the Alpine range in Lombardy to prove their aeolian origin and age of formation. We analysed the granulometry of all genetic horizons of these strongly rubified soils, and a total of 8 samples were collected for luminescence dating purpose. Most of the analysed soil horizons were dominated by silt and were characterized by the s-shaped granulometric curve, typical of loess materials. A particularly high clay content evidenced a strong weathering degree. A deep horizon was particularly clay rich, and it was interpreted as a typical Terra-Rossa horizon. Luminescence dates increased with depth, reaching 122 ka for the deepest loess layer and 453 ka (minimum age) for the Terra-Rossa horizon. The deepest observed loess layer represents the oldest quantitatively dated aeolian deposition in Northern Italy up to now.