An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia
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Date
2017-05
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Instytut Geologii UAM
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Abstract
In the Middle Gauja Lowland, northeast Latvia, dunes are distributed over a vast glaciolacustrine plain that formed
during the retreat of the Fennoscandian ice sheet. Such a direct contact between aeolian and glaciolacustrine sediments
can be used to infer depositional settings and decipher to what extent these sediments bear an aeolian component.
Our proxies, although preliminary, reveal a limited range of variation in grain-size parameters, a significant presence
of quartz grains with silica precipitation and matt-surface grains of various rounding degrees and massive structure
combined with horizontal lamination. These are indicative of periglacial-aeolian depositional conditions in the foreland
of the Linkuva ice-marginal zone. Sedimentary characteristics do not match a single luminescence date of 9.2±0.6 ka,
which significantly postdates the minimum age of the Linkuva ice-marginal zone with 10Be ages between 15.4 and 12.0
ka. Whether deposition started directly after drainage of the Middle Gauja ice-dammed lake or if there is a gap of 2.8–6.2
ka is a matter of debate; only future studies at higher OSL resolution could resolve this.
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Keywords
dune, ice-dammed lake, quartz grains, optically stimulated luminescence, Linkuva ice-marginal zone, Baltic states
Citation
Geologos, 2017, 23, 1, 15-28
ISBN
978-83-232187-4-6