ABSTRACT Karst environments have an inherent complexity that interferes with their hydrogeology comprehension. Hence, isotope hydrology can be a valuable tool to assess trajectory of subsurface flows in an unexplored setting. The study area is located in the Lagoa Santa Karst, an environmental protection area of great economic, cultural and ecological importance, where Neoproterozoic metalimestones accommodate karst-fractured aquifers, characterized by complex water dynamics, essential vulnerability and high productivity. The purpose of this study was to investigate groundwater flow origins of springs using principally environmental stable isotopes 2H and 18O. Rainwater and spring water were sampled and analysed. The LMWL presents angular and linear coefficients strongly similar to those of the GMWL. Spring isotopic signatures, which represent the base flow and present wide-ranging of 2H and 18O, were separated into two groups. The first group can be associated with recent rainwater major contributions, while the second group shows significant evaporated water contributions, largely represented by resurgences. Tritium concentration and physico-chemical parameter data supported this interpretation, pointing that waters of the second group remained more time on the surface and subsurface. Therefore, using isotope tracers to evaluate upper groundwater zone in this tropical karst system is a powerful instrument for water resources management.

中文翻译：

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采用多参数方法的泉水来源，特别关注巴西南部拉戈阿圣喀斯特地区的稳定同位素 2H 和 18O

摘要 喀斯特环境具有内在的复杂性，干扰了他们对水文地质的理解。因此，同位素水文学可以成为评估未勘探环境中地下流动轨迹的宝贵工具。研究区位于Lagoa Santa Karst，这是一个具有重要经济、文化和生态重要性的环境保护区，新元古代金属灰岩容纳岩溶破裂含水层，具有复杂的水动力、基本脆弱性和高生产力。本研究的目的是主要使用环境稳定同位素 2H 和 18O 来调查泉水的地下水流来源。对雨水和泉水进行采样和分析。LMWL 的角度和线性系数与 GMWL 的非常相似。弹簧同位素特征，代表基流和目前广泛的 2H 和 18O 被分成两组。第一组可能与最近的雨水主要贡献有关，而第二组显示出显着的蒸发水贡献，主要以回潮为代表。氚浓度和物理化学参数数据支持这种解释，指出第二组水在地表和地下停留的时间更长。因此，使用同位素示踪剂评估这个热带岩溶系统中的上层地下水区是水资源管理的有力工具。主要以复兴为代表。氚浓度和物理化学参数数据支持这种解释，指出第二组水在地表和地下停留的时间更长。因此，使用同位素示踪剂评估这个热带岩溶系统中的上层地下水区是水资源管理的有力工具。主要以复兴为代表。氚浓度和物理化学参数数据支持这种解释，指出第二组水在地表和地下停留的时间更长。因此，使用同位素示踪剂评估这个热带岩溶系统中的上层地下水区是水资源管理的有力工具。