Can Electromagnetic Surveys Image Deep Crystalline Basement Flow Systems in Extensional Terrains?

结晶基底岩是由结晶矿物组成的岩石。这些基底岩石形成于地球历史的早期，通常埋在较年轻的岩石和沉积物下。这些岩石通常被认为是不透水的，很少或根本没有水流过它们。 然而，结晶基底岩石中的断层或裂缝可以允许流体流动。这项研究使用最先进的仪器对新墨西哥州地表以下近10公里深处的地下进行成像。这项研究考察了在构造活动区的基底岩石中是否以及何时发生流体流动。这项调查的结果和获得的理解可以帮助量化美国西部深层基底岩石中微咸水的年龄和数量。这项研究与水资源管理人员和核废物管理机构有关。该项目包括对水文学和地球物理学领域的研究生和本科生进行培训，支持一名早期职业教师，并支持一个西班牙裔服务机构的研究团队。该项目的主要目标是开发一个新的框架，通过整合流体流动和传输模型，大地电磁（MT）和时间域电磁（TDEM）地球物理调查，地球化学和同位素示踪剂，温度剖面数据，以及裂缝孔径的露头尺度测量。通常，水文地质学家认为结晶基底岩石是不可渗透的。另一方面，地热勘探家承认，基底岩石中的离散断层带可以渗透，但很少关注供给断层带的流体的来源。这项研究提供了一个令人信服的范例，在构造活动区的结晶基底可以有一个相对较高的体积渗透率，作为水，溶质和能量的主要输送机。该项目以格兰德河裂谷为试验床，将地球物理（电磁）、地球化学和实地观测与先进的数值模型相结合，探索这些深度水文系统的流动和输送特征，达到前所未有的深度。这项工作所获得的成果和理解将有助于量化美国西部深层含水层中微咸水的体积、盐度、停留时间和成因--这是一种非常规资源，有可能弥补干旱环境中水和能源的不足。该项目利用了作为新墨西哥州EPSCoR Energize新墨西哥州的一部分获得的基础设施和设备。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Crystalline basement rocks are rocks composed of crystalized minerals. These basement rocks formed early in the history of the Earth and are typically buried under younger rocks and sediment. These rocks are commonly viewed as impermeable with little or no water flowing through them. However, faults or cracks in crystalline basement rocks can permit fluid flow. This study uses state-of-the-art instruments to image the subsurface at depths to nearly 10 km below the ground surface in New Mexico. The study examines if and when fluid flow occurs in basement rocks in a tectonically active region. The outcomes and understanding gained with this investigation can help quantify the age and amount of brackish water that resides within deep basement rocks in the western USA. This research is relevant to water resource managers and nuclear waste management agencies. The project includes training for both graduate and undergraduate students in the fields of hydrology and geophysics, supports an early-career faculty member, and supports a research team at a Hispanic-serving institution.The primary goal of this project is to develop a novel framework to explore deep groundwater flow systems in extensional terrains by integrating fluid flow and transport models, magnetotelluric (MT) and time domain electromagnetic (TDEM) geophysical surveys, geochemical and isotopic tracers, temperature profile data, and outcrop-scale measurements of fracture apertures. Typically, hydrogeologists view the crystalline basement rocks as impermeable. On the other hand, geothermal explorationists acknowledge that discrete fault zones within the basement rocks can be permeable but little attention has been devoted to the source of the fluids feeding the fault zones. This study offers a compelling paradigm in which the crystalline basement in tectonically active regions can have a relatively high bulk permeability, serving as a major conveyor for water, solutes, and energy. Using the Rio Grande rift as a test bed, this project combines geophysical (electromagnetic), geochemical, and field observations with advanced numerical models to explore the flow and transport characteristics of these deep hydrologic systems to unprecedented depths. The outcomes and understanding gained with this effort will help quantify the volumes, salinity, residence times, and genesis of brackish water within deep aquifers in the western USA - an unconventional resource with the potential to offset the deficit of water and energy in arid environments. The project leverages infrastructure and equipment acquired as part of New Mexico EPSCoR Energize New Mexico.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.