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

• Published in: Biogeosciences
• Main Authors: Schirrmeister, Lutz, Schwamborn, Georg, Overduin, Paul, Strauss, Jens, Fuchs, Margret, Grigoriev, Mikhail N., Yakshina, Irina A., Rethemeyer, Janet, Dietze, Elisabeth, Wetterich, Sebastian
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: COPERNICUS GESELLSCHAFT MBH 2017
• Subjects: Ice; laptev; Laptev Sea; permafrost; wedge*; Siberia
• Online Access: https://epic.awi.de/id/eprint/44273/; https://epic.awi.de/id/eprint/44273/1/Schirrmeister2017bg.pdf; https://hdl.handle.net/10013/epic.50613; https://hdl.handle.net/10013/epic.50613.d001

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 ...