地学前缘 ›› 2009, Vol. 16 ›› Issue (6): 66-76.

• 论文 • 上一篇    下一篇

贵州七星洞系统中水文地球化学特征对滴水δ13CDIC的影响及其意义

王世杰,罗维均,刘秀明,谢兴能,周运超,黎廷宇,刘启明   

  1. 中国科学院 地球化学研究所 环境地球化学国家重点实验室, 贵州 贵阳 550002
  • 收稿日期:2009-04-21 修回日期:2009-07-23 出版日期:2009-12-16 发布日期:2009-12-10
  • 作者简介:王世杰(1966—),男,博士,研究员,博士生导师,主要从事喀斯特生态环境和表生地球化学研究。Email: wangshijie@vip.skleg.cn
  • 基金资助:

    中国科学院知识创新工程方向性项目(kzcx2yw306)和创新团队国际合作伙伴计划;国家重点基础研究发展计划“973”项目(2006CB403200);国家自然科学基金项目(90202003);贵州省科学技术基金(黔科合J字［2008］2219)

 Effects of hydrogeochemistry on δ13CDIC values of drip water in Qixing Cave, Guizhou, China and their implications.

WANG Shi-Jie, LUO Wei-Jun, LIU Xiu-Meng, XIE Xin-Nai, ZHOU Yun-Chao, LI Ting-Yu, LIU Qi-Meng   

  1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
  • Received:2009-04-21 Revised:2009-07-23 Online:2009-12-16 Published:2009-12-10

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摘要：

2003年4月至2004年5月,笔者对贵州七星洞(QXD)进行了较为详细的监测,逐月采集了土壤水和洞穴滴水等样品,分别测定了样品的稳定碳同位素组成和水文地球化学参数。结果显示,9个滴水点同期的溶解无机碳同位素值(δ13CDIC)之间存在着大的差异,最大达69‰;δ13CDIC值偏重的Ⅰ组滴水,其Ca、Sr、HCO3、电导率(EC)和方解石饱和指数(SIC)等水文地球化学指标偏小,而Mg/Ca比值偏大,Ⅱ组则相反;不同滴水点的δ13CDIC值分别与相应滴水的Ca、Sr、HCO3、EC、Mg/Ca和SIC等水文地球化学指标之间存在较好的相关关系。进一步分析表明,与土壤水δ13CDIC平均值-99‰相比,Ⅰ组1＃、2＃、6＃、7＃和8＃滴水点δ13CDIC值偏重45‰～57‰,主要是由大量的基岩溶解以及前期方解石沉积(prior calcite precipitation,PCP)共同作用的结果;Ⅱ组3＃、4＃、5＃和9＃滴水点δ13CDIC值偏重06‰～16‰,受基岩溶解和PCP过程影响较小,尤其是9＃滴水点受影响最小。因此,若不考虑基岩溶解和PCP过程影响作用,将会极大地影响洞穴化学沉积物碳同位素记录的准确解释。

关键词: 关键词：洞穴滴水;水文地球化学特征;稳定碳同位素;相关性;贵州七星洞

Abstract:

 Monitoring and sampling of soil waters and cave drip waters during the periods from April 2003 to May 2004 were performed monthly at Qixing Cave, Duyun, Guizhou, southwest China, in order to understand the effects of hydrogeochemisty on δ13CDIC of cave drip waters and their implications for interpreting the potential paleoenvironmental signal preserved in speleothems. The results show that there exists remarkable difference (≤69‰) among δ13CDIC of cave drip waters at 9 sampling sites synchronously. Drip waters are obviously classified into two groups. Compared to Group Ⅱ (3#, 4#, 5# and 9#), Group Ⅰ (1#, 2#, 6#, 7# and 8#) is characterized by heavier δ13CDIC values, smaller Ca, Sr and HCO3 concentrations as well as electrical conductivity (EC) and saturation index for calcite (SIC), and larger Mg/Ca ratio. Good correlations between δ13CDIC of drip water and its corresponding contents of Ca, Sr and HCO3, EC, Mg/Ca, and SIC, respectively, have been found in drip waters. These characteristics imply that δ13CDIC of cave drip waters are controlled to some extend by hydrogeochemistry. In comparison with average δ13CDIC value -9.9‰ of soil waters, δ13CDIC values of drip waters in Group Ⅰ  are heavier up to 45‰57‰, which is caused by the contribution from amounts of bedrock dissolution and prior calcite precipitation (PCP); by contrast, those in Group Ⅱ are slightly heavier (06‰16‰), which is affected less by bedrock dissolution and PCP, especially for 9# drip water. Therefore, the accurate interpretation of δ13C recorded in speleothems can not be guaranteed if not considering the effects of the above mentioned hydrogeochemical processes.

Key words: Key words: cave drip water; hydrogeochemistry; stable carbon isotope; correlation; Qixing Cave, Guizhou