Carbon Isotope Signatures and Polyarenes in the Pedogenic Material of Ice Wedges of the Batagay Yedoma (Yakutia)@en

The carbon isotope signatures and the content of polycyclic aromatic hydrocarbons (PAHs) in the pedogenic material of inclusions in ice wedges of the Batagay yedoma (Yakutia) are studied. The mean concentration of 11 PAHs is 170 ppb (minimum, 7 ppb and maximum, 430 ppb) and the mean δ13С value in soil lipids is -29‰ (minimum, -31.1‰ and maximum, -26.2‰). The prevalent polyarenes in associations are naphthalene homologs and phenanthrene. Trace amounts of heavy PAHs, including benzo[a]pyrene (an indicator of pyrogenic processes), are also detectable. The PAH contents and δ¹³С values in ice wedges show the trend of a decrease with depth. The δ¹³С values and PAH content suggest a pedogenic origin of the deposit: therefore, PAHs originate from plant residues and wildfires. The observed trend of changes in the concentrations of polyarenes along the ice wedge may be associated with the changes in landscapes in the Late Pleistocene.本研究针对雅库特地区巴塔盖永冻冰楔冻土中包裹体的成土物质，展开碳同位素特征与多环芳烃（polycyclic aromatic hydrocarbons, PAHs）含量的分析测定。11种多环芳烃的平均浓度为170 ppb（最低值7 ppb，最高值430 ppb）；土壤脂类中的δ¹³C平均值为-29‰（范围为-31.1‰至-26.2‰）。该组合中的优势多环芳烃为萘同系物与菲；同时可检出痕量的高分子量多环芳烃，其中包括作为热成因过程指示物的苯并[a]芘（benzo[a]pyrene）。冰楔内的多环芳烃含量与δ¹³C值均呈现随深度增加而降低的变化趋势。δ¹³C值与多环芳烃含量共同表明该沉积体为成土成因，由此推断多环芳烃源自植物残体与野火活动。本次观测到的冰楔内多环芳烃浓度变化趋势，可能与晚更新世时期的景观变迁存在关联。