Quantification of peat accumulation rates of European subarctic of Russia based on 210Pb-dating using the constant rate of the supply model (by the example of the Arkhangelsk region)

Abstract

In this work, peat sections from various regions of the European subarctic part of Russia were studied. In peat sections from locations with different environmental conditions and time periods the isotopes of 210Pb and 210Po were determined. The determination procedure included radiochemical preparation followed by dissolution of the salts containing isotopes. The measurements were taken no earlier than 10 hours and no later than 36 hours after preparation of the counting sample. The prepared counting sample was measured on the alpha-beta radiometer. The chronology of peatlands by 210Pb was studied using a Monte Carlo simulation method according the constant rate of the supply model. The approach is implemented in the format of MS Excel spreadsheets, in which the calculated parameters are a peat core diameter, half-life of 210Pb, layer depth, dry weight, total content of 210Pb and concentration of 226Ra. The average rates of sediment accumulation of peat deposits and mass accumulation were obtained and estimated. The maximum mass accumulation rate and the sediment accumulation rate for peat profile no. 1 refer to the closely located 1979 and 1976, respectively. The maximum mass accumulation rate and the sediment accumulation rate for peat profile 2 occur in 1986. The value of the atmospheric flux 210Pb was obtained for the peat-bog ecosystems of the European subarctic part of Russia. The atmospheric flux 210Pb for the studied areas was 80-90 Bq·m2·year-1 which is comparable to data for other territories of Northern Europe. The data obtained showed that the modeling method can be successfully applied to study the chronology bottom sediments in the conditions of the European subarctic part of Russia.