Permafrost

84
Permafrost – affected Soils in Oil and Gas Exploiting Regions
(Bolshezemelskaya Tundra)
C.V. Rusanova
(Institute of Biology, Komi Science Centre, Russian; Academy of Sciences, Syktyvkar, Russia)
Abstract: In the connection with the exploitation of oil and gas deposits in the Barents region,
negative influence is made on the unique soil cover of the tundra. The most widespread types of
destructions are: 1) chemical pollution with crude oil and other organic liquids, 2)
physical-mechanical degradation, 3) damages consequent to the strengthening of exogenous
processes (deflation, solifluction, degradation of permafrost), deterioration in this or that degree
of their qualities. The contents of oil products in contaminated soils 10-20 time exceeds the
maximally allowable coefficient. The studies of oil hydrocarbons (OH) in the soils of the
background ecosystems was carried out. The highest indexes were found in the soils of low
level landscape – geochemical position, which have sorption biogenic, lithogenic, cryogenic,
oxidation reduction barriers. The low contents of OH and a high activity of migration into the
surface waters were revealed for the soils on loose-sandy deposits (Gelic Cambic and Haplic
Podzols), which accumulate OH in the OA, BHF horizons, as well as above the permafrost, The
soils of morainic loams and underlayed by loams are characterized by an increased contents of
OH in comparison with the sands. The increase of OH contents deeply evidences a weak lateral
migration and the inclination for conservation in these soils.
Optical microscope observations carried out on polluted and background soils. The
distinctive from the background features of microfabric of the oil polluted soils serving as
indicators of pollution are found: 1) Gelic Cambic and Haplic Podzols: a) fragmentation of
vegetative remains, b) black thick films and double-layer coatings on mineral grains, c)
dark-brown aggregations of fine dispersed mass between grains. 2) Gelic gleyic Podzols:
fragmentation and chaotic location of plant residues, b) accumulations of coagulated black
aggregates, c) large brown accumulations of fine dispersed mass. 3) Gelic Histosols: a) strong
fragmentation of plant remains, destruction, b) black large clots with cracks of shrinkage. The
possibility and availability of the use of the micromorphological method for the control of
changes of soils at their pollution with oil products are revealed. The effects of hydrocarbons on
the development of cryogenic microfabric is an important factor in designing appropriate
responces to oil spills and other contamination in soils subjected to freezing.
Keywords: Bolshezemelskaya tundra, oil contaminated soils, microfabric.