Yedoma Ice Complex of the Buor Khaya Peninsula (southern Laptev Sea)


Contact
Lutz.Schirrmeister [ at ] awi.de

Abstract

The composition of perennially frozen deposits holds information on the paleo-environment during and following deposition. In this study, we investigate late Pleistocene permafrost at the western coast of the Buor Khaya Peninsula in the south-central Laptev Sea (Siberia); namely prominent eastern Siberian Yedoma Ice Complex (IC). Two Yedoma IC exposures and one drill core were studied for cryolithological (i.e. ice and sediment features), geochemical, and geochronological parameters. Borehole temperatures were measured for three years to capture the current thermal state of permafrost. The studied sequences were composed of ice-oversaturated silts and fine-grained sands with considerable amounts of organic matter (0.2 to 24 wt%). Syngenetic ice wedges intersect the frozen deposits. The deposition of the Yedoma IC, as revealed by radiocarbon dates of sedimentary organic matter, took place between 54.1 and 30.1 kyr BP. Continued Yedoma IC deposition until about 14.7 kyr BP is shown by dates from organic matter preserved in ice-wedge ice. For the lowermost and oldest Yedoma IC part, infrared-stimulated luminescence dates on feldspar show deposition ages between 51.1 ± 4.9 and 44.2 ± 3.6 kyr BP. End-member modelling was applied to grain-size-distribution data to determined sedimentation processes during Yedoma IC formation. Three to five robust end-members were detected within Yedoma IC deposits, which we interpret as different modes of primary and reworked unconfined alluvial slope and fan deposition as well as of localized eolian and fluvial sediment, which is overprinted by in-situ frost weathering. The cryolithological inventory of the Yedoma IC preserved on the Buor Khaya Peninsula is closely related to the results of other IC studies, for example, to the west on the Bykovsky Peninsula, where formation time (mainly during the late Pleistocene MIS 3 interstadial) and formation conditions were similar. Local freezing conditions on Buor Khaya, however, differed, and created solute-enriched (salty) and isotopically-light pore water pointing to a small talik layer and thaw-bulb freezing after deposition. Due to intense coastal erosion, the biogeochemical signature of the studied Yedoma IC represents the terrestrial end-member, and is closely related to organic matter currently being deposited in the marine realm of the Laptev Sea shelf.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
Scopus/ISI peer-reviewed
Publication Status
Published
Eprint ID
44273
DOI 10.5194/bg-14-1261-2017

Cite as
Schirrmeister, L. , Schwamborn, G. , Overduin, P. , Strauss, J. , Fuchs, M. , Grigoriev, M. N. , Yakshina, I. A. , Rethemeyer, J. , Dietze, E. and Wetterich, S. (2017): Yedoma Ice Complex of the Buor Khaya Peninsula (southern Laptev Sea) , Biogeosciences, 14 , pp. 1261-1283 . doi: 10.5194/bg-14-1261-2017


Download
[img]
Preview
PDF
Schirrmeister2017bg.pdf

Download (6MB) | Preview
Cite this document as:

Share


Citation

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item