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  • AGE; Age, uncertainty maximum/old; Age, uncertainty minimum/young; Axioplan 2 and Axiolab pol imaging microscopes; chironomid-inferred temperature reconstructions; Depth, composite; GOS18_composite; Lake Gościąż; Lake Gościąż, Poland; microfacies analyses; PCUWI; Piston corer, UWITEC; Poland; varve chronology; Varve quality index; Varve sub-layer occurrence; Varve thickness; Varve thickness, amorphous organic matter sub-layer; Varve thickness, calcite sub-layer; Varve thickness, diatoms sub-layer; Varve type; δ13Corg; δ18Ocarb  (1)
  • DEPTH, sediment/rock; GOS18_composite; Holocene; Lake Gościąż, Poland; lake sediments; late glacial; PCUWI; Piston corer, UWITEC; varve chronology; Varve thickness  (1)
  • Tiefer See  (1)
Document type
Keywords
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Years
  • 1
    Publication Date: 2021-07-21
    Description: We revise the conceptual model of calcite varves and present, for the first time, a dual lake monitoring study in two alkaline lakes providing new insights into the seasonal sedimentation processes forming these varves. The study lakes, Tiefer See in NE Germany and Czechowskie in N Poland, have distinct morphology and bathymetry, and therefore, they are ideal to decipher local effects on seasonal deposition. The monitoring setup in both lakes is largely identical and includes instrumental observation of (i) meteorological parameters, (ii) chemical profiling of the lake water column including water sampling, and (iii) sediment trapping at both bi‐weekly and monthly intervals. We then compare our monitoring data with varve micro‐facies in the sediment record. One main finding is that calcite varves form complex laminae triplets rather than simple couplets as commonly thought. Sedimentation of varve sub‐layers in both lakes is largely dependent on the lake mixing dynamics and results from the same seasonality, commencing with diatom blooms in spring turning into a pulse of calcite precipitation in summer and terminating with a re‐suspension layer in autumn and winter, composed of calcite patches, plant fragments and benthic diatoms. Despite the common seasonal cycle, the share of each of these depositional phases in the total annual sediment yield is different between the lakes. In Lake Tiefer See calcite sedimentation has the highest yields, whereas in Lake Czechowskie, the so far underestimated re‐suspension sub‐layer dominates the sediment accumulation. Even in undisturbed varved sediments, re‐suspended material becomes integrated in the sediment fabric and makes up an important share of calcite varves. Thus, while the biogeochemical lake cycle defines the varves’ autochthonous components and micro‐facies, the physical setting plays an important role in determining the varve sub‐layers’ proportion.
    Description: Leibniz‐Gemeinschaft http://dx.doi.org/10.13039/501100001664
    Description: Narodowe Centrum Nauki http://dx.doi.org/10.13039/501100004281
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: ICLEA
    Keywords: 552.58 ; 554.3 ; Baltic lowlands ; Tiefer See ; Czechowskie ; calcite varves ; seasonal sedimentation
    Type: article
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  • 2
    Publication Date: 2024-01-03
    Description: To revise the chronology for the Lake Gościąż record, sediment cores were retrieved during two field campaigns in 2015 and 2018. Four overlapping sections were collected using a UWITEC Piston Corer (Ø 90 mm) in the deepest part of Lake Gościąż, Poland (52.583022 N, 19.339946 E). The chronology was obtained by triple varve counting on petrographic thin sections that was complemented by 137Cs measurements and 14C AMS dating of terrestrial plant remains. Additionally, part of the chronology between 520-758 cm was obtained through age-depth modelling. Pollen analysis was performed for seventy one samples, prepared according to standard procedure, and analyzed in three intervals: i) from 1859.9 cm to 1874.4 cm with 2 cm resolution, ii) from 1880.2 cm to 1896.7 cm with 1-2 cm resolution and iii) from 1741.4 cm to 1798.4 cm with 0.5-3 cm resolution. The record is mostly varved and the bottom of the composite profile coincides with the onset of lacustrine sedimentation in the late Allerød at 12,834 +134/-233 varve yrs BP.
    Keywords: DEPTH, sediment/rock; GOS18_composite; Holocene; Lake Gościąż, Poland; lake sediments; late glacial; PCUWI; Piston corer, UWITEC; varve chronology; Varve thickness
    Type: Dataset
    Format: text/tab-separated-values, 11591 data points
    Location Call Number Limitation Availability
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  • 3
    Publication Date: 2024-06-13
    Description: These datasets provide data for the lowest part of a new composite profile GOS18 from Lake Gościąż in central Poland. The composite profile was established using sediment cores recovered in 2015 and 2018 with an UWITEC Piston Corer at 19.6-21.5 m water depth (Bonk et al., in press). Our data covers the time interval from the onset of lacustrine sedimentation in the late Allerød to the early Preboreal. Since Lake Gościąż comprises a continuous, seasonally resolved (varved) and exceptionally well-preserved archive of the Younger Dryas (YD) climate variation, it is highly suitable for detailed investigations of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination), respectively. Our varve chronology is the lowest part of a new floating varve chronology established for Lake Gościąż (central Poland) that has been anchored to the absolute time scale through radiocarbon dating and age modelling (Bonk et al., in press). The here presented varve chronology reaches from the onset of lacustrine sedimentation in the late Allerød until the early Preboreal. Uncertainties for the absolute ages are derived from radiocarbon age modelling and varve counting. The internal varve counting uncertainty for the observed time interval is generally low (+14/-22) due to the mostly excellent varve preservation. Microfacies analyses, including varve counting and measurements of varve and sublayer thickness, have been performed on overlapping large-scale thin sections under an Axioplan 2 and Axiolab pol imaging microscope at magnifications of 50-400x. Thin sections have been prepared from 10 cm long freeze-dried and resin impregnated sediment slices (Brauer & Casanova 2001; doi:10.1023/A:1008136029735). The dataset incorporates the composite depth, age [BP] and age uncertainties [BP] for the varve bottom, the total varve thickness, selected sublayer thicknesses, detrital sublayer occurrence, the different varve types and the varve quality index (VQI).
    Keywords: AGE; Age, uncertainty maximum/old; Age, uncertainty minimum/young; Axioplan 2 and Axiolab pol imaging microscopes; chironomid-inferred temperature reconstructions; Depth, composite; GOS18_composite; Lake Gościąż; Lake Gościąż, Poland; microfacies analyses; PCUWI; Piston corer, UWITEC; Poland; varve chronology; Varve quality index; Varve sub-layer occurrence; Varve thickness; Varve thickness, amorphous organic matter sub-layer; Varve thickness, calcite sub-layer; Varve thickness, diatoms sub-layer; Varve type; δ13Corg; δ18Ocarb
    Type: Dataset
    Format: text/tab-separated-values, 13903 data points
    Location Call Number Limitation Availability
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