Late-glacial to Holocene aeolian deposition in northeastern Europe – The timing of sedimentation at the Iisaku site (NE Estonia)

The Late-glacial and Holocene aeolian inland dune complex at Iisaku (NE Estonia) has been investigated using an accurate and detailed compilation of the sedimentary properties and chronological framework. The quartz grains forming the dunes are very variable, reflecting aeolian, weathering, and periglacial conditions, both prior and after deposition. Although the morphological forms and the sedimentary record point to a dune-like environment, the transport record reflects either a short transport time or/and distance, and a contribution from neighbouring sedimentary environments. Dune development in the area was strongly controlled by the formation of the Baltic Ice Lake (BIL) in front of the retreating glacier. Luminescence ages from the aeolian complex suggest continuous deposition between 13.3 ± 1.2 to 10.5 ± 0.7 ka. However, the chronology of sand deposition also suggests phases in this aeolian activity: (1) at 13.3 ± 1.2 ka and onwards, possibly correlated with the existence of an island separating the BIL and Peipsi Lake, (2) between 12.7 ± 0.8 – 12.5 ± 0.8 ka representing the Younger Dryas cold reversal, (3) between 11.5 ± 0.7 – 10.9 ± 0.8 ka indicating that aeolian deposition continued over the Younger Dryas/Holocene boundary, and (4) early Holocene sand–drift at 10.5 ± 0.7 ka.