Mid- to late Holocene aeolian activity recorded in a coastal dunefield and lacustrine sediments on Andøya, northern Norway

Abstract

In an effort to reconstruct past aeolian activity, a foredune stratigraphy and a continuous lake sediment record from the largest dunefield on Andøya, northern Norway, have been investigated. The dunefield extends landwards in a north-eastward direction and consists of several parabolic dunes, foredunes and blowouts. The sediment record (169 cm) from the nearby lake Latjønna and the foredune stratigraphy (10 m) covers the last 6200 and 3700 cal. yr BP, respectively. Both sites possess sediments deposited after the Tapes transgression maximum (~6800 cal. yr BP), which reached a level of ~7–8 m a.s.l. at the study site. The lake sediment record consists of several units dominated by sand grains interspersed by more organic-rich beds. The core has been examined by x-ray fluorescence (XRF), magnetic susceptibility (MS) and loss-on-ignition (LOI). Mineral grains were detected by wet sieving of the ignition residue (IR), and the influx of sand grains to Latjønna was calculated based on the weight of sand grains >250 µm/cm divided by the accumulation rate determined from a radiocarbon (14C)-based age–depth model. Phases with high influx of sand to Latjønna are recorded around 4800, 4250, 3000–2000, 1850–1750, 1600–600, 450, 300 and 150 cal. yr BP, which coincides with periods of increased storminess recorded in other studies around the North-Eastern Atlantic region. The two study sites show, however, quite contrasting results; high sedimentation rates in the lake record associated with greater aeolian influx correspond to stability in the foredune stratigraphy reflected by the presence of several palaeosols. Because of this out-of-phase behaviour, it is suggested that the foredune is mainly influenced by summer climate and relative sea level (RSL) change, whereas the lake record is more influenced by niveo-aeolian processes transporting sand grains farther inland during winter.