We present the first direct dating by C-14-accelerator mass spectrometry of
three Late Pleistocene syngenetic ice-wedges from the Seyaha cross-section
. They are representative of permafrost with multistage ice-wedges from the
North of Western Siberia. The most important result is the clear vertical
age stratification of the ice, i.e. the old ice is located beneath the youn
g. This shows that a timescale can be assigned to these ice-wedges penetrat
ing down into the permafrost. The age of the ice shows a depth of not more
than 3-5 m for frost cracking; water penetrated into the ice-wedges at that
depth. The lower part of the ice-wedges from the Seyaha cross-section has
been dated between 21 000 and 14 000 BP. (C) 2000 Elsevier Science B.V. All
rights reserved.