Faculty Research

Jeffrey G. Agnew

My research focuses on understanding the causes of biotic evolution. I am especially interested in identifying the roles that constraints and different selective pressures play in shaping morphology through ontogeny. I mostly study dactyls (movable fingers) of recent crabs to develop proxies for predation on and by fossil crabs. I also study tooth variability in modern shark jaws using outlined-based morphometric techniques to help reconstruct dentitions of fossil shark species from isolated teeth.

Nancye H. Dawers

My research focuses on understanding the processes and time-scales over which brittle faults grow, interact and evolve. This includes studying: 1) the structure of propagating fault tips, 2) the pattern of displacement accumulation on faults, 3) how fault displacements scale with fault length, and 4) the temporal evolution of faults via basin analysis and geomorphic studies. At the moment, I have ongoing studies of fault evolution and landscape development in within the Eastern California shear zone, and in the northern Basin & Range. I also have projects in south Louisiana looking at recently active "growth" fault systems, including the contribution of these large fault systems to coastal land loss.

George C. Flowers

I am currently working on the hydrologic history and climate of the Catahoula Basin with emphasis on the impoundment history as reflected in the distribution of old-growth cypress trees in the basin.

Nahid D. Gani

My research focuses on investigating geologic (tectonic and structural) constraints on landscape evolution in both extensional and compressional setting. Primarily, I integrate GIS-based incision model, low-temperature thermochronology and quantitative river profiles. I am also actively involved in paleoelevation and paleoclimate studies of Neogene East Africa, specifically to understand hominin evolution within geologic context. Currently, my research is focused on the Ethiopian Plateau (East Africa), Book Cliff (Utah) and the Himalaya (Nepal).

Nicole M. Gasparini

I am interested in the processes shaping the Earth’s surface, over both short and long time scales. I use numerical models, digital elevation maps, and field observation to quantify surface processes and understand landscape evolution. The main focus of my research is fluvial processes (rivers), and I am particularly interested in the interactions among climate, tectonics, and erosion.

Karen H. Johannesson

The majority of my research efforts are focused on the study of trace element speciation in natural waters. I combine field, analytical, and experimental approaches in order to develop geochemical models that can improve our understanding of the biogeochemical processes that control trace element cycles in the near-surface environment. I am particularly interested in the biogeochemistry of the rare earth elements (REE) and oxyanion-forming trace elements such as arsenic, selenium, chromium, and tungsten. My chemical hydrogeologic research centers on the “evolution” of groundwater compositions along groundwater flow paths, the roles that biogeochemical and microbial processes play in trace element speciation and mobility along flow paths in aquifer systems, and the impact of groundwater discharge to coastal waters.

Ronald L. Parsley

Current research is focused on functional morphology and heterochronous development of Lower and basal Middle Cambrian gogiid eocrinoids (Echinodermata) from Guizhou Province, China. Recent data collection (summer, 2008) based on solute homoiosteles from Ordovician strata of Estonia indicates that the evolution and morphology of brachioles is much more complicated than previously thought.

Brad E. Rosenheim

My research focuses on using isotope geochemistry to 1. assess variability in Earth’s climate system and 2. constrain Earth’s carbon cycles through time. My research group employs an Elementar Isoprime Dual Inlet mass spectrometer that can measure H, C, N, O, and S isotopes as well as a novel ramped pyrolysis radiocarbon preparation device. Our current projects involve assessing the role of the Mississippi River in the global carbon cycle using ramped pyrolysis radiocarbon dating, evaluating the growth patterns of deep sea corals in the Florida Straits to determine their use as paleoclimate proxies, improving chronology of Antarctic sediments that hold climatic keys to past glaciations and deglaciations, and assessing the role of the subtropical Atlantic in climate variability on the recent time scale. The breadth of these projects reflects the research possibilities in Earth sciences employing isotope geochemistry.

Jeffrey M. Sigler

My research focuses on the sources, sinks and transport of pollutants in the Earth's environment, particularly in the atmosphere, and understanding the role of both natural and anthropogenic sources in their biogeochemical cycles. This research draws upon several subdisciplines, including micrometeorology, boundary layer meteorology, and soil science. Recently, I have been most interested in the study of mercury (Hg), a potentially dangerous environmental contaminant if emitted to the atmosphere and subsequently introduced to the aquatic food chain in significant levels. The broad goals of my research are to quantify Hg in the atmosphere in terrestrial, coastal and marine environments, understand the sources and transport of Hg in the atmosphere, and examine the behavoir of Hg in soils.

Kyle M. Straub

My research focuses on the transport of sediment from land through the ocean and into the stratigraphic record. Scales of interest range from the interaction of turbidity currents with channel bends over minutes to the construction and preservation of river deltas over millions of years. The sedimentary bodies that arise from these processes act as both home to millions of people and reservoirs of natural resources. I examine the morphodynamics of these systems using a combination of remote sensing of subsurface sedimentary deposits (visualization and interpretation of seismic data), carefully designed laboratory experiments, field studies of modern and ancient sediment transport systems, and targeted numerical analysis and modeling.

Torbjörn E. Törnqvist

My research is primarily field-oriented and focuses heavily on the Mississippi Delta and the adjacent US Gulf Coast. The central theme revolves around sea-level change during the late Quaternary, with an emphasis on the Holocene. Specific areas of interest include sea level/climate connections as well as the use of relative sea-level records as a proxy for coastal subsidence. I am also interested in the impacts of sea-level change on fluvial, deltaic, and coastal environments. A detailed description of my research activities can be found at the website of the Quaternary Research Group.