Sources of dissolved inorganic carbon in rivers from the Changbaishan area, an active volcanic zone in North Eastern China

作     者：Xue Bai Benjamin Chetelat Yilong Song 

作者机构：Institute of Surface-Earth System Science Tianjin University 92 Weijin Road Tianjin 300072 China School of Environmental Engineering Tianjin University 92 Weijin Road Tianjin 300072 China 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2017年第36卷第3期

页      面：410-415页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 0708[理学-地球物理学] 081501[工学-水文学及水资源] 0815[工学-水利工程] 

基　　金：supported by the National Natural Science Foundation of China through Grant No.41473023 

主　　题：Carbon isotopes Dissolved inorganic carbon Rivers Chemical weathering Changbaishan Active volcanic zone 

摘      要：Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the origin of the CO_2 involved in chemical weathering *** 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 in the composition of these ***,DIC results from the neutralization of CO_2 by silicate *** concentrations vary from 0.3 to 2.5 mmol/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 chemical weathering’s consumption of CO_2 with a magmatic origin,enriched in^(13)C(-5%)and biogenic soil CO_2 with lower isotopic *** highest δ^(13)C values likely result from C isotopes fractionation during CO_2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO_2 varied from less than 20%to more than 70%.Uncertainties in this calculation associated with CO_2 degassing in rivers are difficult to quantify,and the consequence of CO_2 degassing would be an overestimation of the contribution of DIC derived from the neutralization of magmatic CO_2 by silicate rocks.