ORIGINAL ARTICLE
The development and genesis
of a small thaw lake fi lling the Skaliska Basin
during the Late Glacial and Holocene
1 | W. Szafer Institute of Botany, Polish Academy of Sciences, Department of Palaeobotany,
Lubicz 46, 31-512 Kraków, Poland |
Online publication date: 2013-06-26
Publication date: 2013-06-26
Acta Palaeobotanica 2013; 53(1): 69–91
KEYWORDS
macrofossil analysislimnological analysispalaeoecological reconstructionLate GlacialHoloceneSkaliskaBasinnort-eastern Poland
ABSTRACT
The northern part of the Mazury Lake District is marked by the presence of a depression described
as the Skaliska Basin. At the end of the Pleistocene, the Skaliska Basin was the site of functioning of a thaw
lake, within series of laminated clayey sediments were formed. The surface of the clayey sediments was overlain
by a sandy fan. Blocks of dead ice underlying the fan and the overlying surface of the clayey sediments were the
origin of small isolated water basins. Since the Allerød they were fi lled with limnic sediments, passing into peats
towards the upper part. In order to reconstruct the vegetational history of the Skaliska Basin and the conditions
of sedimentation of the lacustrine gyttjas and peats, several sections were obtained from such basins and
subjected to examination of plant macroremains, palaeolimnological analysis and AMS dating. Sedimentation
of lacustrine sediments began with sands with an admixture of silt and peat. The beginning of sedimentation
of lacustrine sands of aeolian origin falls within the Allerød, whereas the end of that process in ca the middle
of the Preboreal. Sands are frequently overlain by a strongly decomposed lacustrine dy sediment. Subsequently
a sequence of detritus gyttja accumulated. The complex of gyttjas is interbedded with occasional Scirpo-Typheti
peats. Sedimentation of lacustrine sediments is followed by accumulation of peats formed within communities
with tall sedges. These communities, according to their compoition, correspond to the associations of Cicuto-
Caricetum pseudocyperi Boer. et Siss. and Caricetum elatae Koch. The upper part comprises peats resembling
the present-day community of Sphagnum centrale, displaying features of a transition bog. Also the occurrence of
Eriophorum vaginatum confi rms changes towards ombrotrophic conditions. The uppermost part of the sections
often comprises heavily decomposed peat with components no longer identifi able by macroscopic analysis.
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