Earth’s Cryosphere, 2017, Vol. XXI, No. 5, p. 89-100
DENDROCHRONOLOGIC RECONSTRUCTION OF GAS-INFLATED MOUND FORMATION AT THE YAMAL CRATER LOCATION
S.P. Arefyev1,2, A.V. Khomutov2,3, K.A. Ermokhina3, M.O. Leibman2,3
1Institute of Northern Development, Tyumen Scientific Centre SB RAS,
P/O box 2774, Tyumen, 625003, Russia; sp_arefyev@mail.ru
2Tyumen State University, 6, Volodarskogo str., Tyumen, 625003, Russia
3Earth Cryosphere Institute, Tyumen Scientific Centre SB RAS, 86, Malygina str., Tyumen, 625026, Russia
Analyzed are tree-ring width chronologies of willow shrubs from the area of a crater formed in Central Yamal as a result of gas emission in October 2013. The crater was formed in place of a mound, probably formed by gassing. We collected samples from willow shrubs on the ejected blocks of soil, the mound slope in situ, and the background shrub tundra. Based on the location of the blocks and their vegetation cover, we reconstructed the original block position on the top and slope of the initial mound. Further analysis of tree-ring width chronologies of the willows demonstrated that formation of the mound lasted for at least 66 years (most likely from the end of the 1940s), during which the mound increased in both diameter and height. We estimated the growth rate of the mound height in 1976–1985 at 8 cm per year. It has been for the first time for the tundra zone that in some loci the relationship has been observed between willow growth and air temperature of not only July but also August. Thus, such relationship can be used as indication of similar mounds. Noted is a recurring inconsistency between tree-ring width of willows on the mound and on the background tundra. Such tree-ring width dissonances have a 6-year periodicity, connected to the planetary tidal effect; identified are the Wolf cycle (10.8 years) and Hale cycle (20–22 years), as well. Gas emission fell into the year of dendrochronological dissonance at the peak of the solar cycle.
Gas-emission crater, gas-inflated mound, tundra shrubs, tree-ring width chronologies, natural cycles