In the period of 1976-95 were obtained more than 200 data on concentration of tritium (3H) in frozen soil and ground ice in permafrost zone of Siberia. Tritium content of upper layer of permafrost varies from 0 to 352 tritium unites (T.U.) depending on age, genesis, criogenic composition and temperature of frozen soils. Significant decrease of tritium content was found in the samples in 1994-95 in comparrision to samples in 1976-83.
The results of investigations point to moisture migration from seasonally thowing layer to permafrost to the depth about 10m. The segregated ice, formed in the result, contents to 30-40% moisture younger than 1953. Intensive evolution of the present-day form of wedge ice, injected ice, segregated ice and buried ice was determed in the system: seasonally thowing soil - permafrost. From 5-10 mm to 20-25 mm of presipitation expending to this process every year. Accumulation of ice in the base of seasonally thowing layer causes permafrost agradation and evolution of ground heaving.
Dr. Alexander B. Chizhov Moscow State University Geological Department Generala Glagoleva 22, k.1, kv.28 123 448 Moscow, RUSSIA Phone: (095) 197 30 95