Late glacial retreat and Neoglacial advance sequences in the Zillertal Alps, Austria

Late Glacial terrain in the Schwarzensteinkees, Hornkees and Waxeckkees forelands of the Zillertal Alps is dominated by sediments deposited by readvancing ice emplaced in the Little Ice Age, starting approximately 550 ± 70 cal 14 C yr BP. Late Glacial ice scoured the massif with remnants of Late Glacial end moraines fronting LIA end moraines and buried paleosols underlying LIA end moraines providing scattered evidence of compositional change and weathering since the Later Dryas. The amount of recovered wood from LIA moraines indicates that the massif was forested for at least part of mid-Holocene times, most likely during the Atlantic Chronozone when, presumably, soil morphogenesis was accelerated. Details of till composition and weathering history provide a pedostratigraphic reconstruction which includes mid-LIA readvances between 400 ± 70 cal 14 C yr BP and 350 ± 70 cal 14 C yr BP. The heavily convoluted character of underlying early LIA or older tills suggests either pre-existing strongly active cryoturbation in a thin Entisol (Regosol) or active push moraine dynamics of advancing warm ice. SEM analysis documents differences in glacial dynamics that may be related to ice thickness, stick–slip motion or clastic load in the ice coupled with rate of movement.