Sources of dissolved inorganic carbon in rivers from the Changbaishan area,an active volcanic zone in North Eastern China
Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in waters from the Changbaishan mountain,a volcanic area in North Eastern China,during the period between June and September 2016 to decipher the origin of CO2 involved in chemical weathering reactions.At a first order,spatial variations of major elements ratios measured in water samples can be explained by a change of the chemical composition of the volcanic rocks between the volcanic cone(trachytes)and the basaltic shield as evidenced by the variations of composition of these rocks.Hence,DIC results from the neutralization of CO2 by silicate rocks.DIC concentrations vary from 0.3 mmol/l to 2.5mmol/l and carbon isotopic compositions of DIC measured in rivers vary from -14.2‰ to 3.5‰.At a first order,the DIC transported by rivers is derived from the consumption by chemical weathering of CO2 with a magmatic origin,enriched in 13C(-5%)and biogenic soil CO2 with lower isotopic compositions.The highest δ13C values probably result from C isotopes fractionation during CO2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO2 vary from less than 20%to more than 70%.
Xue Bai Benjamin Chetelat Yilong Song
Institute of Surface-Earth System Science,Tianjin University,92 Weijin Road,300072 Tianjin,China;Sch Institute of Surface-Earth System Science,Tianjin University,92 Weijin Road,300072 Tianjin,China
国际会议
The 11th International Symposium on Geochemistry of the Earths Surface(GES-11)(第十一届地球表层地球化学国际研讨会)
贵阳
英文
1-6
2017-06-11（万方平台首次上网日期，不代表论文的发表时间）