Age determination and sedimentology of sediment core Lz1101 from the Melles Lake


Autoria(s): Klug, Martin; Bennike, Ole; Wagner, Bernd
Cobertura

LATITUDE: 76.126400 * LONGITUDE: -18.610800 * DATE/TIME START: 2003-08-22T00:00:00 * DATE/TIME END: 2003-08-22T00:00:00

Data(s)

29/01/2009

Resumo

A lacustrine sediment core from Store Koldewey, northeast Greenland, was biogeochemically, biologically and sedimentologically investigated in order to reconstruct long- and short-term climatic and environmental variability. The chronology of the uppermost 189 cm of the record is based on ten 14C AMS age determinations of aquatic mosses. The record covers almost the entire Holocene and revealed changes on multidecadal to centennial scales. Dating of the oldest mosses shows that lacustrine biogenic productivity already began at around 11 cal. kyr BP. This age pre-dates the onset of biogenic productivity in other lakes on Store Koldewey by about 2 kyr. In spite of the early onset of biogenic production organic matter accumulation remained low and minerogenic sedimentation dominated. At about 9.5 cal. kyr BP moss, sulphur, organic carbon and biogenic silica content started to increase, indicating that the environment stabilized and the biogenic production in the lake adjusted to more preferable conditions. Subsequently, the biogenic productivity experienced repeated changes and varied both on long- and short-term scales. The long-term trend shows a maximum during the early Holocene thus responding to increased temperatures during the Holocene Thermal Maximum. Superimposed on the long-term trend, biogenic productivity also experienced repeated short-term fluctuations that match partly the NGRIP temperatures. The most pronounced decrease of biogenic productivity occurred at around 8.2 cal. kyr BP. Perennial lake ice coverage resulting from low temperatures is supposed to have caused decreased lacustrine biogenic productivity. From the middle Holocene to the present repeated decreases of productivity occurred that could be related to periods with severe sea-ice conditions of the East Greenland Current. Besides the dependence on air temperature it therefore demonstrates the sensitivity of lacustrine biogenic productivity in coastal high arctic areas to short-term cold spells that are mediated by the currents emanating from the Arctic Ocean. However, the data also emphasize the difficulties associated with the interpretation of lacustrine records.

Formato

application/zip, 3 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.842070

doi:10.1594/PANGAEA.842070

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Klug, Martin; Bennike, Ole; Wagner, B (2009): Repeated short-term bioproductivity changes in a coastal lake on Store Koldewey, northeast Greenland: an indicator of varying sea-ice coverage? The Holocene, 19(4), 653-663, doi:10.1177/0959683609104040

Palavras-Chave #>1 mm; Age; AGE; Age, 14C AMS; Age, calculated calendar years; Age, dated; Age, dated material; Age, dated standard deviation; Age, maximum/old; Age, minimum/young; Age dated; Age max; Age min; Age std dev; AWI_PerDyn; Beckman Coulter Laser diffraction particle size analyzer LS 200; BP; BP, 2 sigma; bSiO2; Calculated; Carbon, organic, total; carbonate free; d13C Corg; d13C std dev; D50; Dated material; delta 13C, organic carbon; delta 13C, standard deviation; Depth; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Depth bot; Depth top; Element analyser, Metalyt CS-1000S (ELTRA Corp.); Element analyser CNS, Elementar Vario EL III; Grain 25%; Grain 75%; Grain quartile 25%; Grain quartile 75%; Isotope ratio mass spectrometry; Lab no; Lithologic unit/sequence; Median, grain size; Moss; Moss index; Opal, auto analysis (Müller & Schneider, 1993); Opal, biogenic silica; organic carbon; Periglacial Dynamics @ AWI; S; Sample, optional label/labor no; Sample mass; Samp m; Size fraction > 1 mm, gravel; Stratigraphy; Sulphur, total; TOC; total; Unit; Visual description
Tipo

Dataset