A revised chronology for aeolian activity in subarctic Fennoscandia during the Holocene

Detailed sedimentological studies and parallel sampling for 14 C and infra-red stimulated luminescence age assays were undertaken at six sites lying beyond and below the tree-line with the objective of establishing the historical development of aeolian landforms in Lapland. The main issues were: (a) the timing of dune activity and processes of stabilization; (b) the specific processes responsible for the past and contemporary activity. New data indicate that many of the primary dunes were active for several millennia after deglaciation. Diachronous stabilization at both local and regional scales appears likely. Initial stabilization occurred in local interdune areas and where regional dune fields were colonized by pine (generally before 7 ka). Local large dunes and some regional dunefields only became stable around 4.3 ka, when the regional groundwater table rose and late pine colonization was possible. The latest episode of aeolian activity dates from ad 1100–1650 across the area. A unique deflation triggering factor was not identifiable, suggesting that several agents acted in combination. Climate-vegetational parameters, especially the‘Little Ice Age’ event, together with reindeer trampling, appear responsible for the continuing aeolian activity at the tundra sites. At the margin of the pine forest zone, forest fires may be the cause of aeolian reactivation.