extended abstracts - Geomorphic Processes and Geoarchaeology

Geomorphic processes and geoarchaeology
PERMAFROST AS AN ARCHAEOLOGICAL ENVIRONMENT
Pitulko V.V. 1 , Pavlova E.Y. 2
1
Institute for the History of Material Culture, RAS, St. Petersburg,
Russia, pitulkov@rambler.ru
2
Arctic and Antarctic research institute, St. Petersburg, Russia, pavloval@rambler.ru
Permafrost is a global phenomenon, most spread in Asia and in the northern part
of North America. In Russia, it covers about 60 % of the territory. Typically these are a
remote and/or low populated area which partly causes low frequency of
archaeological research.
As a natural conservation agent, the permafrost plays an important role for
archiving environmental proxy records including osteological remains and biological
materials both of animal and human origin, and archaeological finds particularly made of
nondurable (organic) materials such as wood, bone (antler, ivory), or fibrous substances
of plant or animal origin.
Generally, permafrost is defined as any earth material that remains below 0° C for
at least two years (on the contrary to diurnal or seasonally frozen ground). Deposits of
different genesis (e.g., alluvial, colluvial, aeolian or even bedrock) may constitute
permafrost formations. Accordingly freezing can be epigenetic (after the deposition), or
syngenetic (if contemporary to sedimentation). But in many cases the permafrost is of
polygenetic nature.
Ice content is the most important characteristic of the permafrost. It can contain a
high percentage of ice or may have practically no ice at all. Ice-rich permafrost contains
20 % to 60 % of ground ice. Epi- or syngenetic ice-wedges are another large constituent
of the ice-rich permafrost. Specific form of perennially frozen deposits is known in arctic
and sub arctic Siberia namely Ice Complex deposits.
Insulation, atmospheric heat, and water are the worst enemies of the permafrost.
This changes landscapes quickly and dramatically effects preservation of archaeological
sites in permafrost areas, particularly the sites of Pleistocene age, and may lead to the
total destruction of them. Therefore the only survey strategy for these areas will be to
monitor zone of potential interest with expectation to locate archaeological material as
soon as it becomes exposed. Logic of spatial distribution for archaeological sites in the
permafrost areas is basically the same as elsewhere, and then regional waterways should
first serve as a survey network. The only survey strategy for these areas will be to
monitor zone of potential interest with expectation to locate archaeological material as
soon as it becomes exposed.
Not every archaeological site located within the permafrost region is frozen. This
depends on local environmental settings, history of sedimentation, and type of the matrix
sediment, that generally determine the thickness of active layer. Thus, many of Holocene
and Terminal Pleistocene sites of Siberia and Alaska are not frozen while maritime sites
of the same areas are mostly frozen although their materials were deposited within past
2000 years [2]. Even younger sites studied far south of the Arctic – for instance, burial
mounds in Mountain Altai area, Russia are frozen. However, these sites as well as burial
mounds in Kazakhstan are probably the evidence for use of artificially induced frost
conditions resulted from human created structures, made with a purpose to prevent the
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