Fluid Flow and Growth of Active Salt Structures at Decadal Timescales: Paradox Basin, Utah

该项目旨在量化蒸发岩（盐）矿床中的流体流动如何控制上地壳的三维脆性应变，以及溶质转移及其在地球表面和地下之间的联系。这项研究将有助于了解瞬态流体通量如何在几天到几十年的时间尺度和几十米到几公里的距离上驱动短期脆性应变。该研究小组将通过1：5，000比例的实地测绘和横截面的制作、干涉合成孔径雷达场景的分析以及在快速滑动的边界断层上安装一个三分量伸缩仪（蠕变仪）来确定活跃地表变形的特征。此外，研究人员还将评估地表水和地下水流经或直接流入埋藏盐的模式和速率，以及其对岩石强度的影响，这取决于水力弱化和溶解。将进行三维力学建模，以测试受观测到的地表应变、流体流量、地下水建模、结构地质和地形制约的模型。目标是充分表征淡水如何通过盐系统移动，如何通过溶解调节塑性应变，以及岩盐强度的变化，以及地形在耦合表面和地下过程中的作用。工作？更广泛的意义包括理解盐系统中的流体流动和应变如何以其他手段无法获得的尺度演变。研究人员特别感兴趣的是确定塑料盐流中的瞬时浪涌如何响应地表径流和地下水补给的季节性涌入。该野外工作位于犹他州东部的Paramiti蒸发岩盆地，该地区以其非常好的暴露岩石和丰富的可用地表和地下数据而闻名。这项工作将建立在最近在伊朗西部和以色列死海的无压盐体中发现的瞬态浪涌的基础上。这些结构由突现的圆顶和纯岩盐流组成，是类似于冰川的地质结构的现代例子，与墨西哥湾等蕴藏着巨大石油储量的地区的特征相似。这项研究将确定控制盐结构变形和生长的条件，并将其与淡水流入和盐水流出等条件联系起来。这些研究将利用以往研究中没有的广泛技术和数据。因此，最终目标是确定控制和指导其发展的物理条件，以便这可以普遍应用于世界各地的其他盐结构。在全球范围内，这项工作是在盐盆地的碳氢化合物的负责任的资源勘探的兴趣。例如，2010年在墨西哥湾造成石油泄漏的深水地平线油井正在钻到一个盐结构中，井喷的原因是流体压力的意外增加。此外，这项工作有望量化盐水流入科罗拉多河和浅层地下水及其对美国西南部最大淡水来源水质退化的影响。

This project is aimed at quantifying how fluid flow in evaporite (salt) deposits controls 3D brittle strain in the upper crust, in addition to solute transfer and it's connections between Earth's surface and subsurface. The research will help understand how transient fluid flux drives short-term brittle strain at timescales of days to decades and distances of tens of meters to kilometers. The research team will characterize active surface deformation with 1:5,000 scale field mapping and construction of cross sections, analysis of InSAR scenes, and installation of a three-component extensometer (creep meter) across a rapidly slipping boundary fault. In addition researchers will assess patterns and rates of surface and groundwater flowing through or directly into buried salt and its effect on rock strength as governs by hydraulic weakening and dissolution. Three-dimensional mechanical modeling will be undertaken to test models constrained by observed strain at the surface, fluid flux, groundwater modeling, structural geology and topography. The goal is to fully characterize how fresh water moves through the salt system, how that modulates plastic strain by dissolution and changes on the strength of halite and the role topography plays in coupled surface and subsurface processes. The work?s broader significance includes understanding how fluid flow and strain in salt systems evolves at scales not available by other means. The researchers are particularly interested in determining how transient surges in plastic salt flow might respond to input of the seasonal influx of surface runoff and groundwater recharge. The field work is located in the Paradox evaporite basin in eastern Utah, a region noted for its extraordinarily well-exposed rocks and wealth of available surface and subsurface data.This work will build on the recent discovery of transient surges in unconfined salt bodies in western Iran and the Dead Sea in Israel. These structures, which consist of emergent domes and flows of pure rock salt are modern examples of geologic structures analogous to glaciers and are similar to features in areas such as the Gulf of Mexico that contain great petroleum reserves. The research will define the conditions that control deformation and growth of salt structures and relate this to conditions such as the inflow of fresh water and outflow of saline brines within them. These studies will utilize a wide array of techniques and data previously unavailable in past studies. The ultimate goal is thus to define the physical conditions that control and guide their development in order that this may be applied in general to other salt structures around the world. On a global scale, this work is of interest to responsible resource exploration in salt basins for hydrocarbons. For instance the Deepwater Horizon well that created the oil spill in the Gulf of Mexico in 2010 was being drilled into a salt structure, and the cause of the blowout was an unforeseen increase in fluid pressure. In addition, this work holds the promise to quantify the saline brine influx into the Colorado River and shallow groundwater and its effect on the degradation of water quality in the largest source of fresh water in the southwestern United States.