Paleoclimatic indicators from permafrost sequences in the Eastern Taymyr lowland

• Main Authors: Siegert, C., Derevyagin, A.Y., Shilova, G.N., Hermichen, W.D., Hiller, A.
• Other Authors: Kassens, H., Bauch, H.A., Dmitrenko, I.A., Eicken, H., Hubberten, H.-W., Melles, M., Thiede, J., Timokhov, L.A.
• Format: Book Part
• Language: unknown
• Published: Springer, Berlin, Heidelberg 1999
• Subjects: Taymyr; Ice; permafrost; Thermokarst; wedge*
• Online Access: https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=8413; https://doi.org/10.1007/978-3-642-60134-7_38

Permafrost sequences in the Labaz Lake area were investigated to reconstruct their paleoenvironmental history during the Late Quaternary using geocryological field studies, sedimentological, geochemical, stable isotopic and palynological analyses in connection with radiocarbon dating. The current results show that during post-Zyryan (Early Weichselian) times denudation and accumulation in this area was dominated by processes connected with the decay of an ice cover, formed at least during the Zyryan stadial. As a result of the specific peculiarities of glacier ice thawing in a territory with continuous, low- temperature permafrost, buried glacier ice bodies were preserved until the present time. The most intensive decay of glacier ice occurred during the first warming stage of the Kargin (Middle Weichselian) Interstadial more than 40000 yr BP. The formation of extensive lake depressions within the glacial deposits is connected with these times. About 40000 yr BP, a surface stabilization occurred, and syncryogenic deposits with thick polygonal ice wedges (Ice Complexes) and peat beds were formed. Subsequent warming phases, apparently connected with increases in precipitation, led to a new activation of glacier ice decay, and to the accumulation of additional lacustrine and fluvio-lacustrine sediments. Palynological and stable isotope data from ground ice suggest a continual trend to a cooler and more continental climate from the Kargin Interstadial to the Sartan stadial times. During the maximal cooling period, polygonal ice wedges in dried-up lacustrine deposits formed. At the termination of the Pleistocene, lacustrine sedimentation seems to have reactivated in reaction to short climate improvements. Thermokarst lakes were formed in this period. Extensive peat accumulation started at the end of the Boreal and spread to flat lacustrine depressions during the Atlantic. Since the Subboreal, a drying up of lakes and gradual increasing of permafrost aggradation can be inferred.