Postglacial permafrost depositional history of Grøndalen, West Spitsbergen
To shed light on the postglacial landscape evolution on the western coast of Nordenskiöld Land (West Spitsbergen), drilling and outcrop sampling was performed in the framework of the Russian Scientific Arctic Expedition on Spitsbergen (RAE-S) between 2015 and 2022. The transect near Barentsburg stretches over 20 km and comprises 19 drill locations between 5 and 25 m depths below surface on the marine terraces at Isfjorden, along the Grønfjorden, in the Grøndalen and in the Iradalen. Special emphasis was given to the study of pingos. Permafrost cores were obtained with a Russian portable gasoline powered rotary drilling rig (UKB 12/25). The core pieces of 79 to 109 mm in diameter were lifted to the surface every 30–50 cm. For each core segment visible features like granulometry, color, organic content, sediment type and ice structures were described. In some of the boreholes ground temperatures were measured. Analyses of gravimetric moisture content, stable water isotope composition, and ion content of water extracts from permafrost deposits have been carried out. Further studies of grain-size distribution, mass-specific magnetic susceptibility, organic components (TOC, TC, TN, δ13C) as well as radiocarbon dating are in progress. First results of this ongoing effort have been published in recent years on pingo properties, formation and distribution (Demidov et al. 2019, 2021, 2022) and on geocryological and hydrogeological conditions (Demidov et al., 2020), while the paleo-environmental and paleo-landscape aspect is only partly studied yet (Verkulich et al., 2018) and subject to further research. As the area of West Spitsbergen became ice-free about 14 400 years ago, permafrost formation and periglacial landscape evolution covers parts of the Late Glacial and the entire Holocene. The complex interplay of glacial (e.g. retreat), periglacial (e.g. deposition) and marine (e.g. transgression) processes superimposed by climate variability over time define the local permafrost history.