重庆北温泉地热水碳硫同位素特征研究  

Environmental significance of carbon and sulfur isotopes of the North hot spring in Chongqing

作　　者：肖琼[1,2] 沈立成[3] 杨雷[3] 伍坤宇[3] 王鹏[3] 

机构地区：[1]中国地质科学院岩溶地质研究所/国土资源部岩溶动力学重点实验室,广西桂林541004 [2]联合国教科文组织国际岩溶研究中心,广西桂林541004 [3]西南大学地理科学学院/三峡库区生态环境教育部重点实验室,重庆400715

出　　处：《水文地质工程地质》2013年第4期127-133,共7页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助项目(41072192);重庆市科委院士专项(CSTC;2010BC7004)

摘　　要：重庆市北碚区北温泉景区分布有多处自然出露温泉点,选取其中流量大于2000m3/d的北温泉(BWQ)和水文站(SWZ)两处泉点进行监测,结果显示:泉水水化学类型为SO4—Ca型,pH呈中性,其阳离子主要为Ca2+和Mg2+,阴离子主要为SO24-和HCO3-,阳离子当量变化范围为31.74～40.12 meq/L,阴离子当量变化范围为29.05～35.08meq/L。温泉水中δ13CHCO-3的值为-4.84‰～-9.73‰,计算得出CO2的δ13CCO2值集中在-11.91‰～-16.81‰之间,其参与水-岩反应的CO2为幔源和土壤混合成因。δ34SSO2-4值为30.29‰～32.19‰,与四川盆地下三叠统嘉陵江组石膏中的δ34SSO2-4值(28.3‰～35.4‰)一致。联系温泉水中阴阳离子含量、δ34SSO2-4值与δ13CHCO-3的值认为地表雨水补给进入的是下三叠统嘉陵江组碳酸盐岩地层,发生水-岩反应且水-岩反应主要为石膏的溶解,其次是CO2进入储水层与围岩发生水化学作用生成HCO3-。The scenic of the North hot spring is located in Beibei,Chongqing and several natural hot springs occur in this area.Two springs with discharge of over 2000 m3/d are monitored.Hydrochemical style of these springs is SO4-Ca type and pH is of neutrality.The main cations are almost Ca2+ and Mg2+ and the major anions are SO2-4and HCO-3♂.The cation equivalent ranges from 31.74 to 40.12 meq/L and antion equivalent is between 31.74 and 40.12 meq/L.The value of δ13CHCO-3 in these hot springs is between-4.84‰ and-9.73 ‰,and the calculated value of δ13CCO2 is between-11.91‰ and-16.81‰,indicating that the CO2 Participating in water-rock reaction is mixed by the CO2 originated from mantle and soil.The value of δ34SSO2-4 ranges from 30.29‰ to 32.19‰,which is consistent with the δ34SSO2-4PPP value of gypsum(28.3‰~35.4‰) in the Jialingjiang Group of the Lower Triassic in the Sichuan Basin.The chemical features,δ34S SO2-4 value and δ13CHCO-3 value suggest that the surface water sinks into the reservoir bed(carbonate rocks) in the Jialingjiang formation of the Lower Triassic and the water-rock reaction in the reservoir bed is mostly the dissolution of gypsum,and the second reaction is CO2 weathering carbonate rock.

关 键 词：重庆北温泉 δCHCO- δSSO- 水-岩反应 

分 类 号：P314[天文地球—固体地球物理学]