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

Abstract

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. MethodsWe analysed the granulometry of all genetic horizons of these strongly rubified soils and a total of 8 samples were collected for luminescence dating purpose. ResultsMost 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. ConclusionsThe deepest observed loess layer represents the oldest quantitatively dated aeolian deposition in Northern Italy up to now.

The past in dust: current trends and future directions in Pleistocene geoarcheology of European loess

“…Due to their eolian origin, loess deposits are widely analyzed by luminescence dating, which determines the age of the accumulation of quartz and feldspar minerals after a bleaching event, usually the last sunlight exposure during eolian transport before deposition (e.g. Bösken et al ., 2017; Lomax et al ., 2019; Stevens et al ., 2020; Stone and Fenn, 2020; D'Amico et al ., 2021). Depending on the available grain size, single grain or single aliquot techniques are typically used.…”

Unraveling the Mystery of Water-Induced Loess Disintegration: A Comprehensive Review of Experimental Research

“…Regarding the formation of loess, there have been many arguments. However, the hypothesis of aeolian origin for loess has been accepted by more people in recent years [4,5]. The genetic hypothesis of loess is shown in Figure 1 [6].…”