Holocene thermokarst and pingo development in the Kolyma Lowland (NE Siberia)

Abstract

Ground ice and sedimentary records of a pingo exposure reveal insights into Holocene permafrost, landscape and climate dynamics. Early to mid‐Holocene thermokarst lake deposits contain rich floral and faunal paleoassemblages, which indicate lake shrinkage and decreasing summer temperatures (chironomid‐based TJuly) from 10.5 to 3.5 cal kyr BP with the warmest period between 10.5 and 8 cal kyr BP. Talik refreezing and pingo growth started about 3.5 cal kyr BP after disappearance of the lake. The isotopic composition of the pingo ice (δ18O − 17.1 ± 0.6‰, δD −144.5 ± 3.4‰, slope 5.85, deuterium excess −7.7± 1.5‰) point to the initial stage of closed‐system freezing captured in the record. A differing isotopic composition within the massive ice body was found (δ18O − 21.3 ± 1.4‰, δD −165 ± 11.5‰, slope 8.13, deuterium excess 4.9± 3.2‰), probably related to the infill of dilation cracks by surface water with quasi‐meteoric signature. Currently inactive syngenetic ice wedges formed in the thermokarst basin after lake drainage. The pingo preserves traces of permafrost response to climate variations in terms of ground‐ice degradation (thermokarst) during the early and mid‐Holocene, and aggradation (wedge‐ice and pingo‐ice growth) during the late Holocene.

Past climate and continentality inferred from ice wedges at Batagay megaslump in the Northern Hemisphere's most continental region, Yana Highlands, interior Yakutia

“…Following Murton et al (2017), there are hints that the MIS 3 in northern areas of northeast Siberia was a time of general climate stability even though the interstadial climate was not monolithic. In particular, a warmer period around 40 kyr BP is well known from several palaeoecological proxies for some of the study sites (Wetterich et al, 2014) and from ice wedges of the well-dated Bykovsky Peninsula section (Meyer et al, 2002a (Fig. 9).…”

“…If samples were smaller than approximately 200 µgC, the CO 2 produced by combustion with the EA was directly injected into the hybrid ion source of the Ionplus MICADAS using the gas interface system (GIS) (Fahrni et al, 2013). For larger samples, the CO 2 produced was graphitized using the Ionplus AGE3 system (automated graphitization system; Wacker et al, 2010c). The radiocarbon content of the samples was determined alongside size-matched reference standards (oxalic acid; NIST 4990c) and blanks (phthalic anhydride; Sigma-Aldrich 320065) using the Ionplus MICADAS dating system (Synal et al, 2007;Wacker et al, 2010a), and blank correction and standard normalization were performed using the BATS software (Wacker et al, 2010b).…”

Geochemical signatures of pingo ice and its origin in Grøndalen, west Spitsbergen

“…Mackay, 1986). Pingo ice and sedimentary inventories were investigated and furthermore employed in palaeoenvironmental reconstructions in the Mackenzie Delta in Canada N. Demidov et al: Geochemical signatures of pingo ice and its origin (Hyvärinen and Ritchie, 1975), on Seward Peninsula in Alaska (Wetterich et al, 2012;Palagushkina et al, 2017), in Siberia (Ulrich et al, 2017;Chizhova and Vasil'chuk, 2018;Wetterich et al, 2018), where they are called bulgunniakhs, and in northern Mongolia (Yoshikawa et al, 2013;Ishikawa and Yamkhin, 2016).…”

“…Ross et al, 2005;Rossi et al, 2018) and combined chemical and physical investigation of the properties of pingo ice (e.g. Yoshikawa, 1993;Yoshikawa and Harada, 1995). Unlike in other permafrost regions, stable isotope properties of the pingo ice were rarely studied on Spitsbergen (Matsuoka et al, 2004).…”

Pingo development in Grøndalen, West Spitsbergen

“…Mackay, 1986). Pingo ice and sedimentary inventories were investigated and furthermore employed in palaeoenvironmental reconstructions in the Mackenzie Delta in Canada (Hyvärinen and Ritchie, 1975), on Seward Peninsula in Alaska (Wetterich et al, 2012;10 Palagushkina et al, 2017), in Siberia (Ulrich et al 2017;Chizhova and Vasil'chuk, 2018;Wetterich et al, 2018), where they are called 'bulgunniakhs', and in northern Mongolia (Yoshikawa et al, 2013;Ishikawa and Yamkhin, 2016).…”