(Table S1) Radiocarbon dates of organic matter from Lena Delta ice wedges ...

• Main Authors: Meyer, Hanno, Opel, Thomas, Laepple, Thomas, Dereviagin, Alexander Yu, Hoffmann, Kirstin, Werner, Martin
• Format: Dataset
• Language: English
• Published: PANGAEA 2015
• Subjects: organic matter; radiocarbon; river delta; ORDINAL NUMBER; Sample ID; Site; Sample code/label; Age, dated; Age, dated standard deviation; Probability; δ18O; Lithologic unit/sequence; Age, dated material; Multiple investigations; Age, 14C AMS; Age, 14C calibrated, IntCal13 Reimer et al., 2013; Calculated; Mass spectrometer Finnigan Delta-S; Permafrost Research Periglacial Dynamics @ AWI AWI_PerDyn; Arctic; Reimer; Ice; lena delta; lena river; permafrost; wedge*; Siberia
• Online Access: https://dx.doi.org/10.1594/pangaea.842166; https://doi.pangaea.de/10.1594/PANGAEA.842166

Relative to the past 2,000 years, the Arctic region has warmed significantly over the past few decades. However, the evolution of Arctic temperatures during the rest of the Holocene is less clear. Proxy reconstructions, suggest a long-term cooling trend throughout the mid- to late Holocene, whereas climate model simulations show only minor changes or even warming. Here we present a record of the oxygen isotope composition of permafrost ice wedges from the Lena River Delta in the Siberian Arctic. The isotope values, which reflect winter season temperatures, became progressively more enriched over the past 7,000 years, reaching unprecedented levels in the past five decades. This warming trend during the mid- to late Holocene is in opposition to the cooling seen in other proxy records. However, most of these existing proxy records are biased towards summer temperatures. We argue that the opposing trends are related to the seasonally different orbital forcing over this interval. Furthermore, our reconstructed ... : The study area is situated in the central part of the Lena River Delta (72°00'-72°45'N and 125°00'-127°15'E) in Northern Siberia. In this area two (out of three) river terraces were sampled:(1) the first Lena River terrace comprising the active part of the delta, which was formed from mid Holocene to present.(2) the third Lena River terrace, where the work focused on Holocene cover deposits above the Ice Complex with a height of ca. 25 m. ...