Late Holocene ice-wedge polygon dynamics in northeastern Siberian coastal lowlands

• Published in: Arctic, Antarctic, and Alpine Research
• Main Authors: Lutz Schirrmeister, Anatoly Bobrov, Elena Raschke, Ulrike Herzschuh, Jens Strauss, Luidmila A. Pestryakova, Sebastian Wetterich
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2018
• Subjects: permafrost; cryolithology; radiocarbon dating; paleoecology; rhizopods; pollen; plant macro-fossils; geo; envir; Indigirka; Kolyma; Antarctic and Alpine Research; Arctic; Ice; Tundra; wedge*
• Online Access: https://doi.org/10.1080/15230430.2018.1462595; https://doaj.org/article/9b121a38d88f4b47bfb615477d9d0e2a

Ice-wedge polygons are common features of northeastern Siberian lowland periglacial tundra landscapes. To deduce the formation and alternation of ice-wedge polygons in the Kolyma Delta and in the Indigirka Lowland, we studied shallow cores, up to 1.3 m deep, from polygon center and rim locations. The formation of well-developed low-center polygons with elevated rims and wet centers is shown by the beginning of peat accumulation, increased organic matter contents, and changes in vegetation cover from Poaceae-, Alnus-, and Betula-dominated pollen spectra to dominating Cyperaceae and Botryoccocus presence, and Carex and Drepanocladus revolvens macro-fossils. Tecamoebae data support such a change from wetland to open-water conditions in polygon centers by changes from dominating eurybiontic and sphagnobiontic to hydrobiontic species assemblages. The peat accumulation indicates low-center polygon formation and started between 2380 ± 30 and 1676 ± 32 years before present (BP) in the Kolyma Delta. We recorded an opposite change from open-water to wetland conditions because of rim degradation and consecutive high-center polygon formation in the Indigirka Lowland between 2144 ± 33 and 1632 ± 32 years BP. The late Holocene records of polygon landscape development reveal changes in local hydrology and soil moisture.