Associate Director, MMRI
Associate Professor, Geology and Geological Engineering
111 Brevard Hall, University, MS 38677
My research focuses on understanding the dynamics behind paleoenvironmental changes and landscape evolution due to natural geologic process, gradual and abrupt climatic fluctuations, neotectonics, and anthropogenic activities. I use a multidisciplinary approach to accomplish my research goals, which includes 1) geologic and geomorphic mapping, to understand the processes acting on a landscape; 2) luminescence (OSL, TL), terrestrial cosmogenic nuclide (TCN), and radiocarbon geochronology, to help quantify process rates and rates of change; 3) sediment coring and detailed core analyses in the UM Core Analysis and Paleoenvironmental Research Laboratory, to understand the geologic framework and sedimentary architecture of the subsurface; 4) a variety of geophysical methods such as ground penetrating radar, electrical resistivity, and seismic reflection and refraction, to expand the high-resolution studies to larger areas and integrate it into 3D and 4D system-scale landscape models .
Using geophysics to understand the shallow geologic framework of the National Mall and Memorial Parks in Washington, D.C. and map the trend of a Quaternary fault
M.S. student: Kristian Macias, 2020-2022
Collaborators: U.S. Geological Survey Earthquake Hazards (Tom Pratt), U.S. Geological Survey Luminescence Dating Lab (Shannon Mahan)
This project used ground penetrating radar, electrical resistivity, and refraction microtremor seismic (ReMi) to map a fault inferred to lie under our nation’s capital on published USGS maps. The fault location is based on three known fault exposures in DC, but whether these are small, local uplifts or one, continuous fault is uncertain. Luminescence dating from a hand-dug pit at the National Zoo in 2018 indicates the gravel is ~450 ka. A new pit was dug in the coarse-cobble gravel, and a second luminescence sample was collected to verify the relatively young age of the fault.
Geochemical and XRD Analysis of an Anomalous Clay in the Upland Gravel Complex of Crowley’s Ridge: Weathered Tephra, Glacial Slackwater Lake, or a Local Catchment Deposit?
M.S. student: Trevor Dempsey, 2020-2022
Collaborators: Texas Tech University (Dr. Branimir Segvic), Arkansas Geological Survey (Scott Ausbrooks)
Thin sections, EDS on an scanning electron microscope (SEM), XRD analyses, and geochemical analysis are being used to compare this clay layer to other regional clays and determine its origin. The clay is ubiquitous on this part of Crowley’s Ridge and is found within a very coarse, braided gravel deposit that may be glacial outwash.
Calibrating Subsurface Interpretations of Airborne Electromagnetic Data for the Mississippi Valley in Northeastern Arkansas using Multi-proxy data from Continuous Cores and Optically Stimulated Luminescence Dating
M.S. student: Jodi Messick, 2020-2022
Collaborators: US Geological Survey Lower Mississippi Water Science Center (Burke Minsley, JR Rigby, Ryan Adams), U.S. Geological Survey Luminescence Dating Lab (Shannon Mahan)
This project drilled five continuous (4-inch diameter) rotosonic cores to depths ranging from 45 meters to 110 meters in Eastern Arkansas in the summer of 2021. Two cores were drilled in the Western Lowlands (west of Crowley’s Ridge) and three were drilled in the Eastern Lowlands. The goal of the project is to use data from the cores to help calibrate the AEM data by identifying unknown conductive layers present in the data. Up to 60 luminescence samples will be taken from the cores to determine the ages and aggradational rates of the sediments that comprise the alluvial aquifer.
Upcoming research opportunities for M.S. and Ph.D. students (fall, 2022)
Are the coarse-grained alluvial fans on the Mississippi valley walls and along Crowley’s Ridge significant recharge zones for the Mississippi Alluvial Aquifer?
Two positions for 2 Ph.D. students, or one M.S. student and one Ph.D. student
Full tuition waiver and a 1-year of Research Assistantship for each position, following years depend of pending funding but Teaching Assistantships are available
The Mississippi valley is one of the most productive agricultural areas in the country, and the intensive withdrawal of water from this important natural resource grows every year and is rapidly depleted the water supply. Current research at the USGS and USDA includes studies of induced, or artificial recharge through engineered pathways, yet the recharge through natural pathways has not been fully studied or quantified.
For the past ~75 years, previous researchers have not regarded these fans as significant geologic units, evident by their absence from valley cross sections (see Fisk, 1944, Saucier, 1994, and Blum and Tornqvist, 2000 for examples). However, longitudinal profiles of some of the fan surfaces appear to plunge below the ground, suggesting they may significantly extend into the subsurface (Fig. 2). Furthermore, recent AEM data collected by the USGS (Burton et al., 2019) suggests these fans may be extensive and there are at least two generations of alluvial fans. A smaller, younger (Holocene?) fan at the surface which is underlain by a much larger, thicker, and significantly more extensive pre-Holocene fan. Results from these projects will be a large step towards understanding the hydrogeologic stratigraphy of fans and how they affect recharge to the aquifer.
There are two, 1-year RA positions for prospective students to work on this important problem, funded by the U.S. Geological Survey’s EDMAP program. RA funding in additional years may be available depending on future budget levels and pending grants, but if these are not successful there are TA positions available. The selected students will create a geologic map of a 7.5-minute quadrangle, one along the margins of the eastern Mississippi valley wall (Tocowa, MS quad) and one along the margins of Crowley’s Ridge (Harrisburg, AR). The project will focus on geophysical and geologic framework mapping and hydrogeologic characterizations of the fan sediments to determine whether they are hydraulically connected to the aquifer, and if so, to quantify their recharge contributions.
These are field-based projects that will require significant time in the field and in the Paleoenvironmental Analysis Lab. The student will learn traditional geologic mapping and other field methods as well as how to operate a Giddings soil probe, to use a WINK vibracoring system, how to install piezometers and pressure transducer data loggers, how to collect surface infiltration measurements with automated dual-head infiltrometers, and the geophysical methods of ground penetrating radar and electrical resistivity. They will also learn to split, describe, sample and run a suite of measurements on drilled sediment cores that may include laser particle size analysis, magnetic susceptibility, portable XRF, XRD, and spectrophotometric analyses.
Developing a high-resolution, multi-proxy terrestrial paleoclimate record of the mid-south during the MIS 8 glacial period from loess on Crowley’s Ridge.
Collaborators: Texas Tech University (Dr. Branimir Segvic), Arkansas Geological Survey (Scott Ausbrooks), Illinois State Geological Survey (Dave Grimley, Sebastien Huot)
Ph.D. student needed
Full tuition waiver and a Teaching Assistantship available, Research Assistantship may be available from pending grant
This thick loess section on Crowley’s Ridge was deposited during MIS 8 and MIS 5c. Younger loess deposits are absent or very thin.
Luminescence dating revealed that nearly half of a 15m thick section of loess on Crowleys Ridge was deposited during MIS 8, making it one of the thickest known sections of loess from a glacial stage in the Mississippi River valley that very little detail is known for. This project will collaborate with multiple researchers from other universities and will include detailed sampling of the loess for analyses that will include total carbonate, magnetic susceptibility, XRD, XRF, spectrophotometry, particle size, stable oxygen and carbon isotopes, gastropods identifications, luminescence dating, and the analyses of detrital zircons and pollen.
Where is the fault that produced the 1886 Charleston, South Carolina earthquake?
Collaborators: NC State University (Dr. Lewis Owen), U.S. Geological Survey Earthquake Hazards (Tom Pratt)
M.S or PhD. student needed
Full tuition waiver and a Teaching Assistantship available, Research Assistantship may be available pending future grant
The fault that produced the Mw 7 earthquake in Charleston, South Carolina in 1886 remains unidentified, and in fact there are multiple competing models for where faults even exist in the Charleston area. Preliminary ground penetrating radar (GPR) data combined with reprocessed seismic data has identified several near-surface faults in the area. This project will build on that research and use high-resolution GPR and ER surveys to pinpoint faulted coastal plain horizons, drill sediment cores of the faulted horizons, use luminescence dating, and possibly open a trench for the purposes of locating the fault that produced the strongest historic earthquake to strike the eastern seaboard.
GPR profiles from the Charleston area. Dashed lines are faults identified in seismic reflection data.
Investigating the Hovey lake fault system in the Wabash Valley seismic zone (WVSZ): understanding how Paleozoic structures created in a different stress regime are deformed by Holocene reactivation
Collaborators: U.S. Geological Survey Earthquake Hazards (Bill Stephenson), University of Kentucky (Dr. Ed Woolery)
M.S or PhD. student needed
Full tuition waiver and a Teaching Assistantship available, 1-year Research Assistantship may be available pending grant funding
Recently published research (Counts et al., 2021) identified a Holocene fault in the WVSZ that produced a >Mw 6.5 earthquake 3,500 years ago, which appears to be part of a large, reactivated structure. This project will build on that research and do a paleoseismic investigation of the Hovey lake fault using drilling, geophysics, luminescence dating, and trenching.