 |
| Titel |
Past freeze and thaw cycling in the margin of the El'gygytgyn crater deduced from a 141 m long permafrost record |
| VerfasserIn |
G. Schwamborn, H. Meyer, L. Schirrmeister, G. Fedorov |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 3 ; Nr. 10, no. 3 (2014-06-10), S.1109-1123 |
| Datensatznummer |
250116981
|
| Publikation (Nr.) |
 copernicus.org/cp-10-1109-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| The continuous sediment record from Lake El'gygytgyn in the northeastern
Eurasian Arctic spans the last 3.6 Ma and for much of this time
permafrost dynamics and lake level changes have likely played a crucial role
for sediment delivery to the lake. Changes in the ground-ice hydrochemical
composition (δ18O, δD, pH, electrical conductivity, Na+,
Mg2+, Ca2+, K+, HCO3-, Cl-, SO4-) of a 141 m long
permafrost record from the western crater plain are examined to reconstruct
repeated periods of freeze and thaw at the lake edge. Stable water isotope
and major ion records of ground ice in the permafrost reflect both a
synsedimentary palaeo-precipitation signal preserved in the near-surface
permafrost (0.0–9.1 m core depth) and a post-depositional record of thawing
and refreezing in deeper layers of the core (9.1–141.0 m core depth). These
lake marginal permafrost dynamics were controlled by lake level changes that
episodically flooded the surfaces and induced thaw in the underlying frozen
ground. During times of lake level fall these layers froze over again. At
least three cycles of freeze and thaw are identified and the hydrochemical
data point to a vertical and horizontal talik refreezing through time. Past
permafrost thaw and freeze may have destabilised the basin slopes of Lake
El'gygytgyn and this has probably promoted the release of mass movements from
the lake edge to the deeper basin as known from frequently occurring
turbidite layers in the lake sediment column. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|