Research Projects
Planetary Geology: Acidic environmentsAs scientists look for life outside Earth, candidate planetary settings with extreme conditions are often considered. Extreme acidic environments are common features both on Earth and Mars. On Mars, unique surface topographies and mineralogical assemblages that are indicative of past extreme acidic conditions occur in many regions across the planet suggesting that acidic alteration may have been a key process at local and regional scales throughout Martian geologic history. On Earth, acidic environments are often associated with abandoned mine lands where oxidation of pyrite and other materials produces waters that are acidic and loaded with poisonous metals. Even though these acid, heavy-metal-containing waters are toxic to most life forms, communities of acid-loving microorganisms not only survive but they also thieve in such acidic waters. Such microorganisms are responsible for the formation of acid drainage and thus are important both economically and from an environmental perspective.
Our research group, led by Dr. Liliana Lefticariu, has been studying the mineralogy, geochemistry, and biology of acidic environments on Earth with the ultimate goal of identifying habitability factors for extreme acidic environments on Mars. In parallel, our research group examines the use of acidophilic organisms in remediation of acid mine drainage as well as on the use of microbially-mediated processes for metal recovery from waste waters and acid mine drainage. Oxygen isotope analysis of tree-ringsThe climate is usually highly variable with large fluctuations in precipitation on both temporal and
spatial scales which leaves many regions prone to severe droughts and floods. Variations in precipitation can have major social and economic consequences as a large portion of the population is dependent upon agriculture production. Changes in the natural variability of earth’s climate system due to anthropogenic modifications of the atmospheric composition are correlated with natural disasters, such as floods and droughts. Tree-rings, also known as growth rings, have been used by scientists to decipher (1) past aspects of ecologic conditions in a certain area (most prominently climate), (2) archeology, and (3) C-14 dating of woody materials. Recent advances in stable isotope techniques have allowed the use of stable isotope analysis (commonly oxygen, carbon, and hydrogen) from individual tree rings for palaeoclimate reconstructions with impeccable annual resolution and statistically defined confidence limits. One such study was designed to identify the relationships between climate parameters, such as precipitation, and oxygen isotope values of tree ring a-cellulose extracted from exactly dated tree rings of Pterocarpus angolensis trees growing in the arid to semiarid Mzola region of western Zimbabwe. The results are to date show that that oxygen isotope values of P. angolensis tree rings can be used as natural indicators of paleoclimate in southern Africa. A geochemical model of sulfate contaminant transport, Saline Valley Aquifer, Gallatin County Illinois
The Saline Valley Conservancy District (SVCD) formed in 1980 to provide a source of drinking water to many communities in Southern Illinois. The SVCD well field located in the thickest, most productive region of the Saline Valley Aquifer lies directly adjacent to a reclaimed coal mine. Transport of contaminants from the abandoned coal mine has been shown to be responsible for groundwater contamination and deterioration of water quality in the surrounding area, including the Saline Valley Aquifer. This project is set out to understand the temporal and spatial migration of contaminants from the coalmine waste pile into the Saline Valley aquifer. The geochemical data used in this project includes historical data that has been collected over the past 30 years by the IEPA, Saline Valley Conservancy District and the United States Geologic Survey. The main focus will be given on the temporal changes of sulfate, which is the major contaminant in the groundwater system.
Sulfate reducing bioreactor dependence on organic substrates for long-term remediation of acid mine drainageExcessive concentrations of metal contaminants identified in coal-generated acid mine drainage (AMD) associated with abandoned mines pose environmental challenges in the Midwestern U.S. Although many promising technologies have succeeded in providing short-term, low-cost systems for treatment of acid mine discharges, long-term treatment efficiency has been unsuccessful. Sulfate-reducing bioreactors have been employed as a passive technology for the treatment AMD. However field studies demonstrate that long-term efficiency critically depends on the properties of organic substrates and their ability to support sustained microbial sulfate reduction. In this study we conducted field-scale experiments at the Tab-Simco
site to constrain the role of various organic substrates in remediation of
coal-generated AMD. Tab-Simco is an abandoned coal mine located in southern
Illinois that discharges AMD with pH of 2.7 and average concentrations (ppm) of
dissolves ions: 900 Fe, 220 Al, 40 Mn and 4500 SO4. We constructed
(1) five reactors containing limestone and alternating proportions of herbaceous
and woody materials, and (2) one control reactor containing only limestone. For
each experiment, we are monitoring the temporal trends in field parameters, effluent chemistry, mineralogy of solid precipitates,
and microbial communities.
Connectivity of the Tisza River System: a geochemical perspectiveThe Tisza River is the longest tributary of the Danube River and drains much of the Carpathian Mountains in Central Europe. A diverse geologic history in the region has resulted in a variety of rock types throughout the drainage basin. Each of these rock types are characterized by unique chemical compositions, and waters interacting with these rocks produce specific chemical signatures, allowing us to trace the surface waters to the rocks that they drain and better understand the natural inputs into the
river system. For the Tisza River Basin, the use of strontium isotopes could prove to be important in the understanding of the connectivity of the river system and the sources of chemical inputs. How these isotopic ratios, coupled with other conservative tracers, change downstream provides further insights into the chemical and physical processes that govern riverine geochemistry in the Tisza River Basin. Coal weathering: Field experiments of simulated weathering of coal stockpiles and coal refuse disposal areasCoal mining and processing generates stockpiles of coal and processing waste (fine and coarse refuse). Weathering of these materials can significantly increase the concentration of dissolved chemical species such as sulfate, iron, aluminum and manganese in mine discharge. A series of laboratory and field experiments were designed since 2008 to simulate the impact of long-term weathering coal and coal refuse with the goal of finding practical solution to coal waste disposal and improved efficiency of material handling. Recently, we started a new series of field experiments. The main objective of this study is to demonstrate through field-scale column leaching experiments and geochemical testing, that co-disposal of coarse coal processing waste (CCPW) and fine coal processing waste (FCPW) will provide both the geotechnical stability needed to lower refuse facility liabilities and the geochemical environment necessary to minimize sulfate discharge. In addition, a small amount of low-cost limestone sand added to the CCPW and FCPW mixture can further increase refuse fill stability by lowering moisture content. At the same time, the added limestone may greatly improve refuse chemistry through the production of alkalinity. The results of this research will be used to develop and implement innovative concepts for engineered co-management of FCPW and CCPW.
Distribution of Rare Earth Elements in Fluorite
Rare earth elements (REE) are a group of 17 precious metals that are vital to the technology industry. Although they are relatively common throughout the crust of the earth, the ore deposits are exceedingly rare. Locally, in southern Illinois the geologic structure known as Hicks Dome may prove to be a future mineral source of these REE. The object of this research is to explore the relationship between REE concentration in the mineral fluorite and distance from Hick’s Dome, as well as to discover
what the highest REE concentrations may be. Although previous research has shown unusually high concentrations of REE within breccia rocks underneath the surface of the dome, there is a distinct lack of knowledge on the distributions of REE in fluorite samples from around Hicks Dome. A technique for preventing groundwater flow into the mine during the mining of a thick coal seam in a faulted area with thin overburden
Groundwater flow into the mine can lead to both economic loses and many fatalities. The risk of flooding during mining increases in the presence of faults and thin overburden with sandstone aquifers located in the roof of coal seams. Therefore, it is essential to evaluate groundwater hazards from roof aquifers even without the benefit of having access to extensive hydrogeological data. In this study we put forwarded a method of evaluating groundwater hazards posed by sandstone aquifers from Permian-age coal-bearing formations using geologic and structural data collected in the no. 7 district of Yunhe Coal-mine. The Yunhe Coal-mine is located in southern Shandong province, China, in an area where the density of large to medium faults is 14.4 per km2. To evaluate the groundwater hazards, we propose a main control factors evaluation method (MCFEM), which makes use of an analytic hierarchy process (AHP) for building a model that takes into consideration fault density, structural intersections and endpoint distribution, fault scale index (the sum of all faults throws and lengths per unit area), thickness of sandstone, fold distribution, and rock quality designation (RQD) of the sandstone in the roof of the coal seam. Based on the results of the MCFEM the no.7 coal mining district was divided into five groundwater hazard zones. The results of this study can help mitigate the groundwater hazards at the Yunhe coal mine during exploration and mining. They also can be applied to other mines in which sandstone aquifers are present on top of extractable coal.
Multi-method approach for estimating the failure depth of coal seam floor
An increasing number of coal mines will focus their operations on the coal seams present in the Lower Carboniferous formations of northern China. It is expected the risk of groundwater flow from the Ordovician confined limestone aquifer through the floor of overlying excavations to be significant during mining. This hazard can increase if the aquicludes are damaged during the mining of coal because they will not be able to withstand the water pressure from the confined aquifer. Therefore, estimating the failure depth of a coal seam floor (FDCSF) due to mining is of great significance for avoiding the flooding of the mine and, therefore, assuring a safe and efficient production. At present, theoretical models, laboratory tests, numerical simulations, and in-situ measurement are each useful for investigating the overburden strata failure. However, their individual shortcomings can be solved by actually using all of them. Therefore, multiple methods can compensate for and validate each other and also overcome the limitations of any single method. Geo-mechanical, geophysical, and hydrogeological data collected at the first working face of coal seam no.16 in the Nantun coal mine, Shandong Province, China, were used to calculate the FDCSF. The multiple method approach employed for this purpose made use of the plastic sliding theory, empirical formulas, water injection tests, and numerical simulations. The results showed that the FDCSF value in the working face was 14.6 m, which proved useful for calculating the effective thickness of the water pressure-resistant layer present below the coal seam. The coal seam floor failure depth proved to be an important parameter when preventing groundwater flow into the mine from the underlying aquifer.
Funding Research Opportunities |
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raduate Fellowships
Undergraduate Fellowships
- SEG Foundation (SEGF) Student Research Grants [link]
- Environmental Research and Education Foundation [link]
- American Philosophical Society Lewis & Clark Grant [link]
- Student Research in Mineralogy and Petrology [link]
- ICDD Awards - Ludo Frevel Crystallography Scholarships [link]
- The Lewis and Clark Fund for Exploration and Field Research [link]
- NASA Graduate Student Research Program [link]
- NSF Graduate Research Fellowship Program (GRFP) [link]
- NSF Doctoral Dissertation Research Improvement Grants [link]
- AAPG Foundation's Grants-in-Aid program [link]
- The Association of Applied Geochemists [link]
- Pathfinder Graduate Student Fellowships [link]
- The Melinda Gray Ardia Environmental Foundation [link]
- Cave Research Foundation (CRF) Graduate Research Grants [link]
- EPA Fellowship [link]
- Hertz Foundation: The Graduate Fellowship Award [link]
- Amazon Web Services Research Grants [link] and [link]
- GSA GeoCorps™ America [link]
Undergraduate Fellowships
- SIU REACH Undergraduate Research/Creative Activity Award [link]