Paleotemperature Reconstruction for Freeze-Thaw Processes During the Late Pleistocene Through the Holocene,
MOSCOW STATE UNIV (USSR) DEPT OF GEOLOGY
Pagination or Media Count:
Variations in ground surface temperatures for different regions of the USSR were studied using the basic principles of Milankovitch global climate-change theory and harmonic analysis with cycle periods of 200, 100, 41, 21, and 11 thousand years ka. The amplitude of these cycles has been calculated based on the following assumptions 1 Climatic rhythms are represented as sinusoidal variations of temperature with periods of 200 T, 100 T 1, 41 T2, 21 T3 and 11 T4 ka. 2 Minima of harmonics T1 and T2 occurred between 25 and 26 ka ago, while minima of period T3 occurred between 22 and 23 ka ago in addition, maxima of periods TI and T4 were 5 ka ago. 3 Northern hemisphere deviations from present day temperatures during the last cold epoch were up to 9 deg C in high latitudes, ice-free areas and 5 deg C for lower latitudes during the last warm epoch, these values were 4 and 2 deg C, respectively. Harmonics T2, T3 and T4 were combined in an attempt to refine the paleotemperature variations in different regions of the USSR from the late Pleistocene to the present. This long-term model is tested with a series of computer simulations of perennial freezing that show good agreement with reconstructions of paleopermafrost distribution and with its present vertical structure.
- Geology, Geochemistry and Mineralogy