A5084184568- Geochemistry and Elemental Analysis
- Radioactive element chemistry and processing
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Heavy metals in environment
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Nuclear physics research studies
- Radioactive contamination and transfer
- Mine drainage and remediation techniques
- Metal Extraction and Bioleaching
- Atmospheric and Environmental Gas Dynamics
- Groundwater and Isotope Geochemistry
- Chemical Synthesis and Characterization
- Quantum Chromodynamics and Particle Interactions
- Mercury impact and mitigation studies
- Minerals Flotation and Separation Techniques
- Corrosion Behavior and Inhibition
- Marine and coastal ecosystems
- Electrochemical Analysis and Applications
- Nanowire Synthesis and Applications
- Microfluidic and Capillary Electrophoresis Applications
- Astro and Planetary Science
- Spectroscopy Techniques in Biomedical and Chemical Research
Franklin & Marshall College
2009-2024
Woods Hole Oceanographic Institution
2002-2006
University of Washington
1999-2001
Chadron State College
1987-1997
We present a new model for oxic and anoxic diagenesis of shallow deep‐sea sediments based on an efficient solver steady state pore water solid phase diffusion/reaction/advection equations. The model, called “Muds”, is orders magnitude faster than solvers the corresponding time‐dependent resolves Mn Fe/S geochemistry as well pH CaCO 3 dissolution. speed opens application possibilities that are impossible models, including automatic tuning uncertain parameters, deployment in gridded global...
Following the blowout of Macondo well, a pulse in sedimentation resulted changes sedimentary redox conditions. This is demonstrated by downcore and temporal concentration sensitive metals: Mn, Re, Cd. Sediment cores collected NE Gulf Mexico (GoM) reveal increased after Deepwater Horizon (DWH) blowout. The formation mucous-rich marine snow surface waters subsequent rapid deposition to underlying sediments likely cause. Respiration this material decreased pore-water oxygen shoaled redoxcline,...
The middle Paleozoic (∼420-350 Myr) records a major increase in ocean-atmosphere oxygen levels; however, the timing and pattern of oxygenation are poorly constrained. Two well-dated North American locations Nevada Illinois were used to generate high-resolution U-isotopic profile (δ238U) spanning ∼70 Myr Paleozoic. Stratigraphic geochemical data support interpretation that represents near-primary record global-ocean redox variations. First-order δ238U trends indicate strongly reducing oceans...
Abstract. A growing body of observations reveals rapid changes in both the total inventory and distribution marine oxygen over later half 21st century, leading to increased interest extending oxygenation records into past. Use paleo-oxygen proxies have potential extend spatial temporal range current records, bound pre-anthropogenic baselines, provide datasets necessary test climate models under different boundary conditions, ultimately understand how ocean responds beyond decadal scale...
Abstract. A growing body of observations has revealed rapid changes in both the total inventory and distribution marine oxygen over latter half 20th century, leading to increased interest extending oxygenation records into past. The use paleo-oxygen proxies potential extend spatial temporal range current records, constrain pre-anthropogenic baselines, provide datasets necessary test climate models under different boundary conditions, ultimately understand how ocean responds beyond...
Molybdenum (Mo) in marine sediments has been used as a paleoproxy to provide evidence for past oceanic euxinic and sulfidic conditions through its association with pyrite. Here, we examine the adsorption of Mo pyrite precursors mackinawite greigite assess robustness this during iron sulfide phase transformations. Tetrathiomolybdate (MoS42–) experiments were done using that had characterized powder X-ray diffraction Raman spectroscopy. Adsorption tetrathiomolybdate primarily mixture was...