岩溶洞穴滴水δ13CDIC季节变化特征及其环境意义

Seasonal Variation Characteristics of δ13CDIC of Drip Water in Karst Cave and Environmental Significance

为揭示岩溶洞穴滴水中水文地球化学指标与稳定碳同位素特征及其对外界环境变化的响应,作者在2019年夏季和冬季2个时期分别对麻黄洞进行监测。通过对麻黄洞滴水水化学指标和滴水δC进行监测并利用数理统计方法分析,结果表明:(1)麻黄洞滴水水化学类型为HCO-Ca·Mg型,2个滴水点SIc、SId均大于0,滴水处于饱和状态。(2)麻黄洞滴水水化学指标表现出不同季节和空间的变化趋势,MH1和MH2的滴水δC值呈现出夏季偏轻、冬季偏重的季节变化特征,响应外界降水变化。(3)麻黄洞上覆受人类活动影响,其中产生的SO_(4)^(2)、NO_(3)-等离子介入导致MH1和MH2的δC发生偏重的变化,因此研究麻黄洞气候响需考虑SO_(4)^(2)、NO_(3)-的影响。

In order to reveal the characteristics of hydrogeochemical indexes and stable carbon isotopes of drip water in karst caves and response to external environmental changes,this paper carried out intensive monitoring in Mahuang Cave in summer and winter in 2019.Mathematical statistics was used to analyze the hydrochemical indicators and stable carbon isotope of drip water in the Cave.The results show that the drip water chemical types is HCO-Ca·Mg,both the SIc and SId of the two drip water points are greater than 0,and the drip water in a saturated state.The hydrochemical indicators show the trend of seasonal and spatial variation,and the δCvalues of drip water show the seasonal variation characteristics of low in summer and high in winter in MH1 and MH2,responding to the change of external precipitation.The overlying area of the Cave is affected by human activities,and the intervention of SO_(4)^(2)andNO_(3)plasma produced in the overlying area of the Cave,leads to heavy change of δCin MH1 and MH2.Therefore,the influence of SO_(4)^(2)andNO_(3)should be considered in the study of climate response.