The objective of this study is to find the relationship between the global temperatures and the extent of Siberian permafrost. We use a record of Neogene/Quaternary carbonate cave deposits (speleothems) to access the paleoenvironmental conditions. Speleothems form in caves when rain/snow waters seep from the surface, dissolve carbonate rocks above the cave, which is then re-deposited as secondary CaCO3 inside the cave. No speleothem deposition can occur without flowing water, i.e. when the mean annual temperature is below 0°C. Therefore, speleothems which are found in presently permafrost regions must be relicts from earlier warmer/wetter periods. U-series dating of speleothem deposition periods in caves located on north-south transect of Siberia enables us to reconstruct the timing of past periods of permafrost degradation, tracing the migration of southern boundary of the continuous permafrost in time.
Vaks, A, Gutareva, OS, Breitenbach, SFM, Avirmed, E, Mason, AJ, Thomas, AL, Osinzev, AV, Kononov, AM, and Henderson, GM, (2013) Speleothems reveal 500 kyr history of Siberian permafrost, Science, 340 183-186. doi: 10.1126/science.1228729