Constitution and stability of Siberian permafrost Mikhail Permyakov 1 Albert Duchkov 2

1. Constitution and stability of Siberian permafrost Mikhail Permyakov1 Albert Duchkov2 Institute of Petroleum Geology and Geophysics Novosibirsk, Russia 1permyakovme@ipgg.nsc.ru 2duchkovad@ipgg.nsc.ru

2. Institute of Petroleum and gas Geology and Geophysics (IPGG) (Novosibirsk) • Institute of Geocryology (Yakutsk) • Institute of the Earth’s cryosphere (Tyumen) • Institute of the Earth’s crust(Irkutsk)

3. Permafrost structure

4. Climate fluctuation in Pleistocene and Holocene (according to N.V. Kind) >50 40 30 20 15 10 5 0 th.y-s. Kazanstevskoe (QIII1) interglacial Zyryanskoe (QIII2) glaciation Karginskoe (QIII3) interglacial Sartanian (QIII-IV) glaciation Holocene (QIV) warming 0°C 0°C cold Relict permafrost was formed due to of inclement conditions in Pleistocene.At these time the huge ground massifs had been frozen on the surface and under the sea shallow.Then, during the Holocene warming permafrost was thawing from the surface, but the deep permafrost layer persisted as relict.

5. Heat flow map of Siberia (mW/m2)

6. Southern limit of the extent of the cryolithozone during different periods of the Quarternary (Kondratieva et al., 1993). 1 - Early to middle Pleistocene, 2 - Late Pleistocene (Sartanian time), 3 - Early Holocene, 4 - Climatic optimum of the Holocene, 5 - Late Holocene, 6 - Contemporary times.

7. Khanty-Mansiysk Yakutsk E.S. Melnikov, K.A. Kondratieva, G.F. Gravis, L.N. Kritsuk, S.F. Khrutskyi

8. Thickness of the Siberian permafrost. 1 - isolines of the lower boundary depth (depth of 0C isotherm), meters; 2 - the same for upper boundary (only in West Siberia), 3 - south boundary of permafrost.

9. Surface temperature Contemporary average annual surface rock temperature in Western Siberia Permafrost boundary

10. Permafrost upper boundary depth Permafrost upper boundary in Western Siberia Permafrost boundary

11. Permafrost lower boundary depth Permafrost lower boundary in Western Siberia Permafrost boundary

12. Permafrost thickness Permafrost thickness Permafrost boundary

13. CO2 HSZ Thickness CO2 HSZ Thickness Permafrost boundary

14. CH4 HSZ thickness CH4 HSZ Thickness Permafrost boundary

15. Ta Ts Modern parameters of the West Siberia permafrost along the meridianal cross section. A - Plots of air (Ta) and rock temperature (Ts) at depth of 15-20 m B - Permafrost (P) upper and lower boundaries

16. Temperature field of permafrost

17. Siberia: Temperature of air in the North of Russia(Pavlov, Ananieva, 2004)

18. Examples of the temperature profiles from West Siberia: A – from northern regions (stable permafrost), B – from regions which have non-stable permafrost (constant temperature, geothermal gradient about 0)

19. A B C D West Siberia: A-C – temperature profiles from relict (land-buried) permafrost; D - curves illustrate disintegration of relict permafrost.

20. B Temperature C Temperature A Temperature Examples of the temperature profiles from Vilyui and Predverhoyan depressions: A and C – stable permafrost, B – non-stable permafrost

21. Stability of permafrost

22. Temperature profile A B Temperature Temperature Change of temperature in dry (A) and water-saturated (B) rocks with increase of Ts from -5ºC up to 0ºC for 20 thousand years. 1 - in both cases initial distribution of temperature; (A) 2-5 – temperature profiles in 5, 10, 15 and 20 thousand years after the beginning of change Ts; (B) 2-6 - temperature profiles in 4, 8, 12, 16 and 20 thousand years after the beginning of change Ts.

23. Q – heat flow below the phase boundary; • Qf – heat flow in frozen rocks; • H- the ice melting heat; • W – ice content; • V – rate of frost penetration or thawing. • Near the phase boundary Qf/Q = 1 + HWV/ Q = N • N is a criterion of permafrost temperature fieldstability. • While permafrost is stable: V = 0, Qf = Q and N = 1 • Degradation of permafrost due to a climatewarming: V<0, Qf<Q, Qf/Q = N<1 • Accretion of permafrost due to a cold snap: V>0, Qf>Q, Qf/Q = N>1 • Qf/Q can be used as a tool for studying the temperature fieldstability of the frozen rocks and a course of permafrost evolution. • This technique was applied to different permafrost areas showing thatN<1, i.e. permafrost degrades everywhere

24. Map of modern trends of air temperature increase in the North of Russia, ºC/yr Long-term analysis of meteo data (Pavlov, Ananieva, 2004)suggests that warming takes place everywhere (which results in permafrost thawing with various rate)

25. Possible increase of surface temperature (С) in Siberia if the global climate warming will take place in 21 century (according to Manabe, Wetherald, 1975, 1987; Balobaev, 1994)

26. Prognosis of the temperature changes in different blocks of Western Siberia permafrost during 21 century under influence of the climate warming. 1 – temperature profiles from cold permafrost (Arcticheskaya site, Yamal), 2 - temperature profiles from non-stable permafrost without geothermal gradient (Kostrovskaya site), 3 - temperature profiles from relict permafrost (Urengoi)

27. Permanently frozen ground that will thaw by 2025 by 2050 relatively stable Seasonally frozen ground Expected evolution of permafrost in Russia at the moderate (1-2,5 °C growth in 50 years) scenarios of climate warming to 2020 and 2050 (Pavlov, Gravis, 2000).

28. Rough estimates of expected gas content within the Russian permafrost (V. Yakushev, 2009)

29. Thank you