Collaborative Research: Investigating Lithologic and Stratigraphic Controls on Hydrogeology in Neogene Strata of the Central High Plains Aquifer

合作研究：研究中部高平原含水层新近系地层对水文地质的岩性和地层学控制jon Smith，堪萨斯大学michael Petronis，新墨西哥高地大学，ear1023278abstract高平原含水层占美国所有地下水提取量的近30%。含水层正面临越来越大的发展压力，水位正在经历历史性的下降，这可能严重影响北美大平原的主要农业生产。本研究的目的是研究中部高平原含水层新近系和上覆第四纪单元的地下沉积相、地层格架和年代地层。这些性质控制着含水层的几何形状和水文地质关系，并源于含水和围水地层的形成过程和沉积历史。然而，由于含水层的松散和饱和层段，以前无法从高平原获得高质量的地层信息。为了实现这一目标，我们将使用安装在移动平台上的旋转振动钻机。这种最先进的钻井技术首次提供了一种高效、经济的方法来收集完整的岩心，回收率接近100%。长连续岩心，结合岩性、谱伽马和磁地层岩心测井；稳定同位素化学地层学；以及由温度年代学、光激发发光（OSL）、磁极研究和新近纪沉积物U/Pb定年所施加的地质年代学约束，将为限制地层对比和水文地层结构的合理解释提供关键的时间元素。这项研究将具有全球意义，因为在世界许多地区，陆源新近纪沉积物的异石器时代序列中的含水层处于发育压力之下。通过使用数值模拟来预测不同管理策略对水文地质的反应，可以最有效地实现地下水资源的管理，这些模型依赖于含水层材料及其地层格架的准确表征。

Collaborative Research: Investigating Lithologic and Stratigraphic Controls on Hydrogeology in Neogene Strata of the Central High Plains AquiferJon Smith, University of Kansas, EAR-1023285Michael Petronis, New Mexico Highlands University, EAR-1023278ABSTRACTThe High Plains aquifer accounts for nearly 30% of all groundwater withdrawals in the United States. The aquifer is under increasing developmental stress and experiencing historic declines in water levels that could seriously compromise major agricultural production on the North American Great Plains. The objective of this research is to investigate the subsurface sedimentary facies, stratigraphic framework, and chronostratigraphy of Neogene and overlying Quaternary units in the central High Plains aquifer. These properties control aquifer geometries and hydrogeologic relationships and are derived from the formative processes and depositional histories of water-bearing and confining strata. Quality stratigraphic information from the High Plains, however, has been impossible to retrieve previously due to unconsolidated and saturated intervals of the aquifer. To accomplish this, we will use a mobile platform-mounted rotary-vibratory drill rig. This state-of-the-art drilling technology provides, for the first time, an efficient and cost effective means of collecting intact core with nearly 100% recovery. Long continuous cores, coupled with lithologic, spectral gamma-ray, and magnetostratigraphic core logging; stable isotope chemostratigraphy; and geochronologic constraints imposed by tephrochronologic, optically stimulated luminescence (OSL), magnetic polarity studies, and U/Pb dating of Neogene sediments, will provide the critical time element to constrain permissible interpretations of stratigraphic correlation and hydrostratigraphic architectures. This research will have global import because aquifers in heterolithic successions of continentally derived Neogene sediments are under developmental stress in many parts of the world. Management of groundwater resource is achieved most effectively by using numerical modeling to predict hydrogeological response to different management strategies and such models depend on accurate characterization of aquifer materials and their stratigraphic framework.