The Origin of Badwater in the Edwards Aquifer, Texas: An Integrated Approach to Regional Flow Systems in a Carbonate Aquifer

这项研究旨在评估负责的过程 区域碳酸盐含水层中的天然咸水- 爱德华兹含水层。 这些沃茨存在于 当地称为恶水区（盐度大于 超过1000 mg/l）。 尽管这对环境很重要 含水层和许多以前的研究在这里，假设的起源 劣水带水化学相残留及演化 数量众多且具有推测性。 这项研究将整合一系列 传统的和新开发的分析技术， 爱德华兹含水层的水文和地球化学研究， 沿着并垂直于恶水和 淡水区。 数据库将包括电位计和 主要元素（稀土元素）和稳定元素（H、O、B、S）， 将采集的放射成因（Sr、Nd、U和Ra）同位素数据 新的样品。 这项研究还将包括岩石学和 下白垩统碳酸盐岩的地球化学分析， 构成含水层。 这些数据将用于定量 模拟流体流动、流体-岩石相互作用和流体 在含水层中混合。 元素和同位素参数， 地球化学行为范围很广， 对理论模型的应用至关重要， 限制了五个起源中每一个的过程， 不同的水化学相 这项研究将对我们的 对墨西哥湾区域流动系统的认识 沉积盆地，并将有更广泛的影响， 化学和结构控制区域发展 碳酸盐含水层和含盐地下水的演变。

This research seeks to evaluate the processes responsible for natural saline groundwaters in a regional carbonate aquifer--the Edwards aquifer of Texas. These waters are present in what is locally referred to as the badwater zone (salinities of greater than 1000 mg/1). Despite the environmental importance of this aquifer and many previous studies here, hypotheses for the origin and evolution of the badwater zone hydrochemical facies remain numerous and speculative. This research will integrate a range of conventional and newly developed analytical techniques in a hydrological and geochemical study of the Edwards aquifer both along and normal to the boundary between the badwater and freshwater zones. The data base will include potentiometric and major-element (rare-earth elements), and stable (H, O, B, S) and radiogenic (Sr, Nd, U and Ra) isotope data that will be acquired on new samples. This study will also include petrologic and geochemical analyses of lower Cretaceous carbonate rocks that constitute the aquifer. These data will be used in quantitative models that simulate fluid flow, fluid-rock interaction, and fluid mixing within aquifers. The elemental and isotopic parameters to be studied have a wide range of geochemical behavior, which will be critical for the application of theoretical models to constraining the processes involved in the origin of each of five distinct hydrochemical facies. This study will bear on our understanding of regional flow systems in the Gulf of Mexico sedimentary basin, and will have broader implications for the chemical and structural controls on the development of regional carbonate aquifers and the evolution of saline groundwaters.