Results of permafrost modelling of the lowlands and shelf of the Laptev Sea region, Russia

Permafrost thickness evolution models for the Laptev Sea shelf and coastal lowlands describe a palaeogeographic scenario, a geological model, and the choice of lower and initial boundary conditions. The model covers four clim atic and glacio-eustatic cycles. The temperature zonation of permafrost, th e freezing of seawater-saturated deposits, and the accumulation of ice-rich syncryogenic sediments with fresh ice on the emergent shelf surface are al l included into the model. Different values of geothermal heat flow are use d. Results indicate an increase in the magnitude of oscillations of the per mafrost bottom, an increase in differences in permafrost thickness during t he wanner parts of climatic cycles, a lag in the appearance of the maximum permafrost thickness after the climate extreme, and a degradation of permaf rost an the shelf and coastal lowlands at the present time. Copyright (C) 2 001 John Wiley & Sons, Ltd.