A multimethod dating study of ancient permafrost, Batagay megaslump, east Siberia


A multimethod dating study of ancient permafrost, Batagay megaslump, east Siberia

Murton, J. B.; Opel, T.; Toms, P.; Blinov, A.; Fuchs, M.; Wood, J.; Gärtner, A.; Merchel, S.; Rugel, G.; Savvinov, G.; Wetterich, S.

Dating of ancient relict permafrost is essential for understanding permafrost stability and interpreting past climate and environmental conditions over Pleistocene timescales but presents substantial challenges to geochronology. Here, we date ancient permafrost from the world’s largest thaw slump at Batagay, East Siberia, which potentially provides one of the longest records of Pleistocene environments in western Beringia (East Siberia). We apply four dating methods to the permafrost deposits: (1) optically-stimulated luminescence (OSL) dating of quartz and (2) post-infrared infrared-stimulated luminescence (pIRIR) dating of K-feldspar from sand, (3) ³⁶Cl/Cl dating of ice wedges, and (4) radiocarbon dating of organic material from within wedge ice and its host sediments. Individually, each of the four independent chronometers produces ages consistent with their relative stratigraphic position. Comparability of ages between dating methods is also observed. However, at Batagay quartz OSL appears to date MIS 2/MIS 3 deposits more reliably than K-feldspar pIRIR250, whereas the latter is more consistent with independent chronological controls for older deposits. Collectively, the ages indicate that the lower ice complex developed approximately 650 ka ago during Marine Isotope Stage (MIS) 16, and the upper ice complex approximately 60 to 30 ka ago during late MIS 4 to MIS 3. Sand units below and above the upper ice complex are dated to MIS 6 and 3–2, respectively. Overall, the lower ice complex represents the oldest dated relict permafrost in western Beringia and indicates that thick and cold permafrost at a depth of ~50 m below the ground surface has survived multiple warm interglacials, including the MIS 11c super-interglacial.

Keywords: permafrost; climate; AMS; Siberia; luminescence; dating; OSL; radiocarbon; ice

Related publications

Permalink: https://www.hzdr.de/publications/Publ-30893
Publ.-Id: 30893