Model of the Accumulation of Soil-Sedimentary Sequence of the Ice Complex (Kolyma Lowland)

Based on the example of an exposure at Cape Maly Chukochi, a model has been developed for the accumulation of the soil-sedimentary sequence of the ice complex in the Kolyma Lowland. The distribution of measured magnetic susceptibility of the sediments over the depth has a periodic shape. The specific magnetic susceptibility of the material at the level of (5–25) × 10 –8 m 3 /kg is determined by the presence of fine magnetite crystals in it. The hypothesis is substantiated that the finely dispersed magnetite of the ice complex is of authentic origin. Due to its accumulation, the magnetic susceptibility of the soil increases during the lifetime of the material in the seasonally thawed layer, and its distribution in the soil-sedimentary sequence contains information about the history of the sequence accumulation. The proposed model describes the soil-sedimentary sequence as the result of sediment input to the soil surface with a time-varying intensity of the sedimentary matter flow, which determines the dynamics of the lifetime sediment in the seasonally thawed layer and the period of magnetite accumulation in the soil. The calculated distribution of the sediment transformation degree in the sequence profile is compared with the measured distribution of magnetic susceptibility. Based on the data on the distribution of magnetic susceptibility, the model has been used to reconstruct the accumulation history of the soil-sedimentary sequence.