摘要
重庆地区分布有380条岩溶地下河,是重庆市重要的水资源。为掌握岩溶地下河水稳定同位素地球化学特征及其环境意义,研究了重庆市不同地区51条地下河水体的稳定同位素地球化学特征。研究表明,重庆市岩溶地下河旱、雨季δ18O、δD值均沿大气降水线分布,表明地下河水均起源于大气降水。受雨季降水云团运动规律(环流效应)和区域地形的影响,地下河水δ18O、δD值雨季表现出渝东北地区(渝西地区,渝东地区)<渝东南地区的明显区域分布规律"(<"表示偏负于),旱季由于地下河水在含水层中运动较慢,δ18O、δD值的区域性规律不明显,且由于具有较雨季长的滞留时间,导致其d-excess值明显小于雨季。利用岩溶地下水δ18O值和区域高程建立了二者之间的二元回归模型,揭示了重庆岩溶地下河水旱季δ18O值随高度的变化率为–0.34‰/100 m,雨季为–0.31‰/100 m,这对于区域水循环研究具有重要意义。
Karst groundwater constitutes the important water resources and life support systems in the karst areas, and its geochemical research is an indispensable method for karst aquifer protection. There are approximately 380 subterranean karst streams （SS） which are the important part of the groundwater resources in Chongqing City. The isotope geochemistry of 51 subterranean karst streams in Chongqing shows that all the SS waters originate from modern precipitation because their 3180 and δD values are distributed along the line of GMWL or LMWL, which shows that the evaporation of groundwater does not occur or is not strong. Under the control of movement of rain cloud cluster from south to north （atmospheric circulation effect） and the regional relief, the regional distribution of δ180 and OD for SS in Chongiqng in rain season is in order of northeastern Chongqing 〈 western Chongqing, central area of Chongqing 〈 southeastern Chongqing （the symbol ＂〈＂ means ＂more minus＂）. In dry season, the regional distribution of δ18O and δD for SS is not clear due to the slower movement velocity in karst aquifer. Because of the slower movement velocity and longer staying time in karst aquifer in dry season, the d-excess value of SS in dry season is obvious smaller than that in wet season. Considering the relationship, between the altitude and the mean value of δ180 for SS within 100 m altitude, the authors established the second order polynomial ofkarst groundwater between δ18O and altitude. According to the equations, the δ18O-elevation gradient of karst groundwater in Chongqing is -0.34 %o/100 m in dry season and -0.31%o/100 m in wet season. These results are very useful to the study of the groundwater cycle in karst aquifers. The achievements obtained by the authors are applicable to the reasonable protection and exploitation of subterranean karst streams.
出处
《地球学报》
EI
CAS
CSCD
北大核心
2013年第6期713-722,共10页
Acta Geoscientica Sinica
基金
国家自然科学基金项目(编号:41202185)
国土资源部公益性行业科研专项(编号:201311148)
广西自然科学基金项目(编号:2012GXNSFBA053137)
中国地质调查局地质调查项目(编号:12120113006700)
IGCP/SIDA598项目联合资助
关键词
岩溶地下河
地下水
稳定同位素
重庆
subterranean karst stream
groundwater
stable isotope
Chongqing
