Publications

In low-permeability systems, groundwater may be accompanied by separate-phase fluids, and measured pore water pressures may deviate from those expected in steady-state, single-phase systems. These same systems may be of interest for storage of nuclear waste in Deep Geologic Repositories. Therefore, it is important to understand the relationship between the presence of a separate phase and anomalou

Understanding the evolution of plumes emanating from residual hydrocarbon contaminant sources requires evaluating how changes in source compositions over time cause changes in dissolved plume chemistry as residual sources age. This study investigates such changes at the site of a 1979 crude-oil pipeline spill and is the first comprehensive look at groundwater chemistry associated with a residual h

Geoenvironmental models were formulated by the U.S. Geological Survey in the 1990s to describe potential environmental effects of extracting different types of ore deposits in different geologic and climatic regions. This paper presents a geoenvironmental model for roll-front (roll-type) uranium deposits in the Texas Coastal Plain. The model reviews descriptive and quantitative information derived

The presence of vitrinite in sedimentary rocks of post-Silurian age allows its reflectance to be used to estimate the thermal maturation of organic matter in petroleum systems. Increasing reflectance of vitrinite, which is primarily driven by aromaticity, depends primarily on the time and temperature attributes of its evolutionary pathway. This study evaluated carbonaceous shales proximal to coal

A geoenvironmental assessment methodology was developed to estimate waste quantities and disturbances that could be associated with the extraction of undiscovered uranium resources and identify areas on the landscape where uranium and other constituents of potential concern (COPCs) that may co-occur with uranium deposits in this region are likely to persist, if introduced into the environment. Pri

Although the Atlantic continental margin of the eastern United States is an archetypal passive margin, episodes of rejuvenation following continental breakup are increasingly well documented. To better constrain this history of rejuvenation along the southern portion of this continental margin, we present zircon U-Pb (ZUPb) age, zircon fission-track (ZFT) age, apatite U-Pb (AUPb) age, and apatite

Wastewater generated during petroleum extraction (produced water) may contain high concentrations of dissolved organics due to their intimate association with organic-rich source rocks, expelled petroleum, and organic additives to fluids used for hydraulic fracturing of unconventional (e.g., shale) reservoirs. Dissolved organic matter (DOM) within produced water represents a challenge for treatmen

Rare earth elements and yttrium (REYs) are critical elements and valuable commodities due to their limited availability and high demand in a wide range of applications and especially in high-technology products. The increased demand and geopolitical pressures motivate the search for alternative sources of REYs, and coal, coal waste, and coal ash are considered as new sources for these critical ele

Geological models for petroleum generation suggest thermal conversion of oil-prone sedimentary organic matter in the presence of water promotes increased liquid saturate yield, whereas absence of water causes formation of an aromatic, cross-linked solid bitumen residue. To test the influence of hydrogen from water, organic-rich (22 wt% total organic carbon, TOC) mudrock samples from the Eocene lac

Pollen morphology on its own and in conjunction with other characteristics has elucidated the origin and evolution of various plant groups. Previous studies of fossil pollen rarely discuss the effects of diagenesis and sample preparation on pollen characteristics, i.e., variability in staining, pollen morphology, and pollen wall ultrastructural characteristics. This paper examines the effect of ac

The New Idria serpentinite body in the Coast Ranges of California is a diapir that resulted from the interaction of the migrating Mendocino trench-ridge-transform fault triple junction, transpression, metasomatic fluids, and previously subducted oceanic crust and mantle. Northward propagation of the San Andreas fault progressively eliminated the original subduction zone, allowing seawater to penet

Iron mineral transformations occurring in hydrocarbon-contaminated sites are linked to the biodegradation of the hydrocarbons. At a hydrocarbon-contaminated site near Bemidji, Minnesota, USA, measurements of magnetic susceptibility (MS) are useful for monitoring the natural attenuation of hydrocarbons related to iron cycling. However, a transient MS, previously observed at the site, remains poorly