Earth’s Cryosphere, 2017, Vol. XXI, No. 5, p. 14-23

THE STRUCTURE OF A SITE WITH THERMO-SUFFOSION PROCESSES WITHIN BESTYAKH TERRACE OF THE LENA RIVER, ACCORDING TO GEOPHYSICAL DATA

V.V. Olenchenko1, L.A. Gagarin2, I.I. Khristoforov2, A.B. Kolesnikov2, V.S. Efremov2

1Trofimuk Institute of Petroleum Geology and Geophysics, SB RAS,
3, Acad. Koptyuga ave., Novosibirsk, 630090, Russia; OlenchenkoVV@ipgg.sbras.ru
2Melnikov Permafrost Institute, SB RAS, 36, Merzlotnaya str., Yakutsk, 677010, Russia; GagarinLA@gmail.com

The new data on geological structure of the area with developing thermo-suffosion processes obtained from electrical resistivity tomography and ground penetrating radar techniques allowed geoelectrical imaging of pressure filtration channels, and outlining potential thermo-suffosional sinkholes and collapse structures. Based on the obtained geophysical characteristics, the phenomenon of permafrost degradation was discovered above the intrapermafrost aquifer, to a depth of the active layer base. Permafrost degradation is one of the forces that lead to groundwater infiltration channel collapse, prompting thereby the development of sinkholes on the land surface. The collapsed top layer of the intrapermafrost aquifer changes the direction of groundwater flow, which, in turn, precludes the warming effect of the groundwater and provokes refreezing of the sand massif around thermo-suffosion sinkholes. We found a correlation between variations in electrical resistivity in permafrost and changes in the vegetation cover concentration: the frozen ground resistivity is higher for shaded areas overgrown with a larch forest, than for areas overgrown with sparse pine forest. The research results have provided insights about the formation mechanism of thermo-suffosion sinkholes, and the geometry of water-bearing taliks of the supra/intrapermafrost complex.

Thermo-suffosion, suffosion sinkholes, permafrost, electrical resistivity tomography, ground penetrating radar

DOI: 10.21782/EC1560-7496-2017-5(14-23)