My research focus is in hydrogeology and aqueous & sedimentary geochemistry. My students and I use a variety of techniques including field studies, laboratory experiments and analyses, and groundwater and geochemical modeling to explore the interplay between groundwater and surface waters and water-rock intereactions.

   Specific areas of current interest and some recent studies

• Groundwater hydrology, geochemical evolution of groundwaters, and groundwater interactions in the critical zone:

• Determining how development and climate change  affect groundwater and secondary cements in coastal dune deposits, central Oregon coast.

• Modeling the evolution and thermal history of geothermal waters in the Western Cascades.

• Modeling the effects of thermal energy storage on the porosity & permeability of Columbia River Basalt aquifers, Portland Basin.

• Assessing hydrochemical facies and modeling the evolution of groundwater in the hydrocarbon-rich Piceance Basin, NW Colorado.
  

• Determining the hydrostratigraphy of groundwater flow systems in northern Portland Basin, Columbia River Gorge, upper Deschutes River Basin, and central Oregon.

• Mineral-water reactions that control concentrations of trace elements in soils and water and geogenic hazards:

• Studying the relative mobility of trace elements from weaterhing of black shales, determining their fate and transport in the surface environment.

• Determining mineralogical changes accompanying the hydrous retorting of oil shales.

• Assessing the mobility of arsenic from tuffs and tuffaceous sediments.

• Paleo-environmental reconstruction using sediment geochemistry:

• Modeling paeloceanographic conditions for the formation of Devonian-Mississippian black shales, Kentucky.

• Reconstructing the paleoenvironmental conditions for formation of massive black-shale-hosted phosphate deposits (Mead Peak Member, Phosphoria Formation), southern Idaho and western Wyoming.