Low-temperature mineralogy in groundwater systems

点击翻译按钮获取中文摘要

Groundwater resources must be protected against threats from natural and anthropogenic sources of contamination.  In order to protect this resource, we must understand how potential contaminants migrate from their source areas through geologic materials (soils, bedrock, sand, gravel, clay etc) toward aquifers.  It is known that the migration of most contaminants is slowed by chemical reactions that occur at the surface of mineral grains in these geologic materials.  This research is designed to improve our knowledge of these reactions, and thereby gain a better understanding of controls on the migration of contaminants.     There are two principal objectives: 1) develop techniques for analytical (Scanning) Transmission Electron Microscopy that can provide new insight into chemical properties of minerals and the geochemical environment in which they form, and 2) integrate sub-micron-scale determinative low-temperature mineralogical investigations with groundwater geochemical investigations in order to better understand the solid-phase controls on groundwater geochemistry. The development of new methods for measuring and mapping metal valence in minerals at the nano scale will have broad application within the geosciences, and in material sciences in general.  In the geosciences, this work will benefit research ranging from investigations of the redox state of high temperature igneous and metamorphic rocks, to studies of redox state during low temperature weathering processes.  It will also shed new light on the importance of scale when integrating aqueous geochemical, mineralogical, and numerical modeling techniques for the purpose of predicting the geochemical evolution of groundwater systems.