Peat and peat-mineral heaving mounds of Tambey River valley, north-east of the Yamal Peninsula

Abstract

The research of peat and peat-mineral frost mounds was carried out in September – October 2021 in the northeast of Yamal Peninsula, 50 km north of the village of Tambey. Morphometric data was acquired om ten frost mounds. The wells with the depth of up to 1 m were drilled in 4 out of 10 mounds using electric drill, which outcropped the upper horizons of permafrost. Descriptions were given to seasonally thawed layer and drilled permafrost. Diameter of the mounds located in various landscape conditions varied from 4.5 to 9.8 m, and their heights ranged from 0.5 to 1.5 m. The thickness of seasonally thawed layer on these mounds varied from 28 to 131 cm, while the maximum depth of seasonal thawing was reached on the slope of the hillock, with rare exceptions when it was observed on the top of the hillock, or 1 meter from it. The steepness of hillocks rarely reached 10°, averaging from 3°to 5°. The seasonally thawed layer consisted mostly of the layers of lignite of varying degree of decomposition, rarely replaced by light gray loam (including peaty). Permafrost rocks were also represented by peat with high content of ice.