Current State of Subsea Permafrost on the East Siberian Shelf: Tests of Modeling Results Based on Field Observations

摘要

Modeling of subsea permafrost on the East Siberian Shelf (ESS) was performed with consideration of mechanisms that previously were not taken into account, such as salinity of the permafrost, content of unfrozen water within the permafrost, complex permafrost structure consisting of layers with salt and without salt, and development of thermal karst processes before inundation of the Siberian lowlands during the recent sea transgression. It is shown that the influence of the new mechanisms taken into consideration is critical for the development of destabilization processes in the subsea permafrost and has a significant influence on our concepts about the current state of subsea permafrost on the ESS. Modeling data obtained using the example of the Dmitrii Laptev Strait explain well the prominent anomalies of dissolved methane in the waters of the strait as well as peculiarities in the structure of permafrost drilling cores obtained earlier.