Deciphering the Complex History of Fluid Flow in Lower Carboniferous Carbonate Rocks, Irish Midlands: Geochemistry of Multiple Dolomitizing and Ore-Forming Events

爱尔兰中部地区下石炭统碳酸盐岩流体流动的复杂历史：多个白云化和成矿事件的地球化学Kevin L.Shelton和Jay M.GreggEAR-0106388爱尔兰中部地区由一个天然实验室组成，在那里研究伸展/挤压构造背景下流体流动对白云石化和锌铅矿床的物理、热和地球化学影响。我们的研究探讨了沉积相、早期成岩作用和热液白云石化作用之间的关系，以及它们与爱尔兰下石炭统碳酸盐岩局部和区域流体流动的关系。需要解决的具体问题适用于爱尔兰中部地区以及世界各地类似的伸展/挤压盆地环境：各种多种流体的来源及其流动系统的范围是什么？每种流体系统的相对时间是什么？沿流动路径的关键的流体-流体和流体-岩石相互作用导致热液白云石化和/或矿床沉积？区域规模的流体通过含水层的流动与局部的断裂控制的流动对矿藏开发的相对重要性是什么？我们的研究将通过联合应用碳酸盐岩石学和一些地球化学工具来解决这些问题，包括C，O和Sr同位素，流体包裹体显微测温，以及流体包裹体卤素和微量元素地球化学，包括新的激光烧蚀-电感耦合等离子体质谱技术。这项研究的影响是深刻和及时的。建模师现在正在扩展反应流水文地质-地球化学模型的能力，以模拟地下水化学、岩石蚀变模式和裂隙岩石中的矿化作用。我们研究沿地层和断层路径的盆地流体的化学作用的地球化学数据将为约束爱尔兰中部地区正在开发的深部流体流动理论模型提供良好的基础。

ABSTRACTDeciphering the Complex History of Fluid Flow in Lower Carboniferous Carbonate Rocks, Irish Midlands: Geochemistry of Multiple Dolomitizing and Ore-Forming EventsKevin L. Shelton & Jay M. GreggEAR-0106388 The Irish Midlands comprise a natural laboratory in which to study the physical, thermal and geochemical effects of fluid flow on dolomitization and zinc-lead ore deposition in an extensional/compressional tectonic setting. Our research addresses the relationships among sedimentary facies, early diagenesis and hydrothermal dolomitization, and their relationship to localized and regional fluid flow throughout Lower Carboniferous carbonate rocks in Ireland. Specific questions to be addressed are applicable to the Irish Midlands, as well as to similar extensional/compressional basinal settings worldwide: What are the sources of various multiple fluids and the extents of their flow systems?; What is the relative timing of each fluid system?; What are the critical fluid-fluid and fluid-rock interactions along flow paths that led to hydrothermal dolomitization and/or ore deposition?; What is the relative importance of regional-scale fluid flow through aquifers versus localized fracture-controlled flow for the development of mineral deposits? Our study will address these questions through combined application of carbonate petrology and a number of geochemical tools, including C, O and Sr isotopes, fluid inclusion microthermometry, and fluid inclusion halogen and trace element geochemistry, including new laser ablation-ICP-MS techniques. The impact of this study is profound and timely. Modelers are now expanding the capability of reactive flow hydrogeologic-geochemical models to simulate groundwater chemistry, patterns of rock alteration and ore mineralization in fractured rock. Geochemical data from our studies of chemical interactions of basinal fluids along stratigraphic and faulted pathways will provide an excellent basis for constraining theoretical models of deep fluid flow that are being developed for the Irish Midlands.