ИСТИНА

Two-hundred-thirty-three samples of various types of ground ice from the active layer and permafrost in Siberia were analyzed for tritium content. The samples were collected from bore cores, prospecting shafts and exposures from depths about 0,2 to 13 m. Investigations were carried out at 9 sites located in regions of spreading permafrost islands, discontinuous and continuous permafrost, between 54N and 73N. Tritium was detected in 90% of the samples. Maximum tritium concentration in the permafrost reached 230-323 TU (tritium units), and 300-352 TU in the active layer. Tritium analyses point to intensive moisture exchange between the active layer and the permafrost. The average content of modern moisture in the segregated ice and frost mound ice is about 20%, and in growth ice wedges, 15% and more.