Hydrochemistry and Variation of δ¹³C_DIC of the Qingmuguan Underground River in Chongqing

详细信息   

• 责任者：Qiu Shulan (School of Geographical Sciences of Southwest University ; Chongqing 400715 ; China) ; Jiang Yongjun
• 刊名：Carsologica Sinica
• 出版年：2012
• 卷期：31(3)
• 关键词：地下河 ; underground streams ; 水化学 ; hydrochemistry ; 重庆 ; Chongqing
• 页码：p.279-288
• 图表：4 illus., 2 tables, 11 refs.
• 分类号：1800
• issnNo：ISSN1001-4810
• isbnNo：CN45-1157/P

摘要

In order to determine the source of dissolved inorganic carbon and the matter in the Qingmuguan underground river system, the underground river system is monitored from April, 2010 to January, 2011, and the chemical components, the dissolved inorganic carbon content and δ¹³C_DIC as well as their influencing factors are analyzed. Furthermore, detailed analysis is made to some monitor points in the ploughing season in 2010. The results show that 1） the type of the Qingmuguan underground river water is Ca-HCO₃ that is affected mainly by water-rock action and rainfall;  2） the molar ratio of （Ca^2＋＋Mg²⁺ ）/HCO₃^- in the groundwater varies from 0.6 to 0.72 and is averaged 0.67, which indicating the carbonate dissolution is con- trolled by CO₂, HNO₃ and H₂SO₄ in the soil under the C₃ vegetation cover;  3） the HCO₃^- from carbonate dissolution by carbonic acid account for 56.16% to 81.25 % of the total HCO₃^- concentration in groundwater with a mean percentage of 66.96%, while the HCO₃^- from carbonate dissolution by sulphuric and nitric acids make up 18.75 % to 43.84% of the total HCO₃^- concentration in groundwater with a mean percentage of 33.04 %; and  4） the δ¹³C_DIC in groundwater varies from - 8. 17 % to -13. 68 % with an average value of -10.53 No, the average value of δ¹³C_DIC in ploughing and dry season is -9.25‰ and -12.29 ‰, respectively, which indicates there is a significant perturbation to the cycling and export of inorganic carbon by agricultural activities in karst underground river system.