Digging Through Permafrost in Siberia

Abstract

Permafrost is defined as ground that remains below 0 °C for at least 2 years. As a natural conservation agent, it provides an archive of environmental proxy records including biological materials of vegetable, animal and human origin, and artifacts, particularly those made of organic materials such as wood, bone (antler, ivory), or fibers deriving from plants or animals. Permafrost may contain up to 60 % of ice or virtually none at all. Atmospheric heat and water alter deposits quickly, and dramatically affect the preservation of archaeological sites. Finding sites in this terrain still depends on artifacts or cultural layers exposed by chance. Test pits, aerial and geophysical methods have not been successful except for the most recent sites of approximately past 2,000 years or so. Early Holocene and Pleistocene sites, particularly in Siberia, still remain fully frozen. Not many of them are known up to now, but in all cases, they are encased in ice-rich deposits. Experience of excavating such sites is so far limited to three cases – Zhokhov, Yana RHS, and Berelekh (Pitulko 2008). Excavation strategies are determined mostly by the depth of the site and the degree of icing. Where cover is thin, area excavation can be applied, but under a thick cover of frozen ground, it is necessary to approach from the side in profile. Examples of both these strategies are given here.