Traces of frost activity and ice segregation in Pleistocene loess deposits and till of northern Italy: Deep seasonal freezing or permafrost?

Abstract

This paper describes traces of ice lensing preserved in loessic deposits, in till, and in shelters and cave infillings. Most of the observed traces correspond to seasonal frost activity, rather well-preserved in poorly drained sites or in the shadow of shelters. No distinct evidence of permafrost dating to the Last Glaciation has been found: the preservation of ice lensing traces in soil is poor, due to intense biological activity and dry climate conditions. This shows that during the glacial time, the Po plain belonged to the southeastern European domain, though presently included in the western, sub-Mediterranean climate zone.