Office: 301D Parkinson Lab
I am a broadly trained geochemist with cross-disciplinary links to several areas of geology such as biogeochemistry, economic geology, and coal geochemistry. My specialty is low-temperature geochemistry with an emphasis on the stable isotopes of elements that play key roles in biogeochemical processes. My research is primarily devoted to solving diverse theoretical and practical problems with application in the geological and environmental sciences.
My current research projects focus on the:
Biotic and abiotic fractionation of sulfur isotopes in sedimentary sequences
Distribution and mode of occurrence of trace elements in coal
Mercury isotopes in Illinois coal
Low temperature geochemistry of aqueous systems
Biogeochemistry of acid mine drainage
Experimental investigation of sulfide minerals oxidation
A new and very exciting line of my research examines the origin of sulfate on Mars. The intrinsic association of sulfate minerals with water makes the understanding of sulfate formation more fascinating because of the possible association with life forms. Since sulfate minerals are an archive of past and recent processes on Mars, deciphering the fundamental aspects of their formation is the first step in the geochemical cycling and ultimately the history of water and the potential presence of life during evolution of other potentially habitable bodies such as Europa, for example.
Recent Research Projects
Projects representative of opportunities for research, including collaborative activities, which are, or have been, supported by NSF, ICCI, and other funding agencies:
1). Isotopic fractionation patterns as indicators of oxidation mechanisms of sulfide minerals
Detailed knowledge on the mechanisms of mineral weathering, including thermodynamics, kinetics, and isotope fractionation, is essential to accurately predict their environmental impact. Recently, a new dimension of studying sulfate minerals and acid environments has emerged with the discovery that sulfur is a significant component of surface soil and rocks on other planetary bodies. On Mars, in situ observations made by the various landers have provided multiple lines of evidence for sulfur activity over a prolonged period in Martian history. There has been much speculation about the presence of water on Mars based on existents of hydrous sulfate minerals. Thus, a full understanding of the oxidation mechanisms of sulfide minerals is of fundamental future use in many kinds of environmental, biological, chemical or geological investigations.
2). Distribution and mode of occurrence of sulfur and trace elements in Illinois coal
Coal is largely composed of organic matter, but it is the inorganic matter in coal—minerals and trace elements— that have been cited as possible causes of health, environmental, and technological problems associated with the use of coal. Modes of occurrence of chemical elements, including sulfur (S), mercury (Hg), selenium (Se), and arsenic (As) in coal have been determined mostly indirectly, and to a lesser extent directly. Our goal is to provide an increased understanding of the geochemistry of sulfur and other potentially hazardous trace elements (e.g., As, Hg, and Se) in Illinois coals. This information is needed to generate predictive models for the behavior of toxic chemical elements and to predict the mobility of different chemical elements during the coal fuel-cycle, the ultimate goal of this integrated study.
3). Acid mine drainage-prevention and treatment
Acid mine drainage (AMD) is one of the most significant environmental challenges facing mining industry. Although acid drainage is commonly associated with the extraction and processing of sulfide-bearing metalliferous ore deposits and sulfide-rich coal, acidic drainage can occur wherever sulfide minerals are excavated and exposed to atmospheric oxygen. The principal sulfide mineral that can be easily oxidized when exposed to the atmosphere is pyrite, but others are susceptible to oxidation, releasing elements such as aluminum, arsenic, cadmium, cobalt, copper, mercury, nickel, lead, and zinc to the water flowing through the mine waste. The study of intricate processes associated with sulfide oxidation and the formation of acid drainage are of fundamental use in resolving environmental, chemical or geological problems.
Other current and exploratory projects include several collaborative ventures with colleagues at Southern Illinois University, John Crelling, Ken Anderson, Scott Ishman, Kelly Bender, Yoginder Chugh, Tracy Prowse, and their students and post-docs.
Undergraduate Projects and Opportunities
Four undergraduates are currently working as field and laboratory assistants for projects aimed at understanding the role of microbial sulfate reduction and sulfide oxidation in acid mine drainage systems.
GEOL 111 Geology and the Environment
GEOL 330 The Planets
GEOL 417 Isotope Geochemistry
GEOL 440 Applied Aqueous Geochemistry
GEOL 585 Earth and Space Science for Teachers
GEOL 515 Instrumental Analysis in Geology
GEOL 517 Advanced Topics in Geochemistry
My teaching methodology emphasizes the importance of engaging students in active thinking and problem solving activities. Thus, I feel it is important to provide students not only with the theoretical foundations for understanding geological processes, but also to apply them for solving real-world problems. I am excited to teach both undergraduate and graduate courses in geology and geochemistry. In the case of undergraduate classes I emphasize building a strong foundation of knowledge and skills. For graduate education I put an emphasis on probing concepts and self-directed exploration of the literature. My laboratory is always available to students so that they can develop geochemical projects as part of their studies. I believe that each student should be an active participant in his/her education and learn through field and laboratory experiences involving ever-increasing levels of independence.
Lefticariu, L., Blum, J. D., Gleason, J. D. (2011) Mercury Isotopic Evidence for Multiple Mercury Sources in Coal from the Illinois Basin. Environmental Science and Technology 45, 1724–1729. http://pubs.acs.org/doi/full/10.1021/es102875n
Lefticariu, L., Pratt, L. M., and LaVerne, J. A. (2010) Anoxic pyrite oxidation by water radiolysis products — A potential source of biosustaining energy. Earth and Planetary Science Letters 292 (1), 57–67. http://dx.doi.org/10.1016/j.epsl.2010.01.020
Fischer, M. P., Higuera-Diaz, C. I., Evans, M. E., Perry, E. C., and Lefticariu, L. (2009) Fracture-controlled paleohydrology in a map-scale detachment fold: insightsfrom the analysis of fluid inclusions in calcite and quartz veins. Journal of Structural Geology 31 (12), 1490-1510. http://dx.doi.org/10.1016/j.jsg.2009.09.004
Lefticariu, L., Schimmelmann, A., Pratt, L. M., and Ripley, E. M. (2007) Oxygen isotope fractionation during oxidation of pyrite by H2O2 and its dependence on temperature. Geochimica et Cosmochimica Acta 71 (21), 5072–5088. http://dx.doi.org/10.1016/j.gca.2007.08.022
Perry, E. C., Lefticariu, L. (2007) Formation and geochemistry of Precambrian cherts. In: Treatise on Geochemistry; H. Holland and K. Turekian (Eds.) Volume 7, Sediments, Diagenesis, and Sedimentary Rocks; F.T. MacKenzie (Ed.), 99-113. http://www.treatiseongeochemistry.com
Lefticariu, L., Pratt, L. M., and Ripley, E. M. (2006) Mineralogical and sulfur isotope effects accompanying the oxidation of pyrite in millimolar solutions of hydrogen peroxide at temperatures from 4 to 150 °C. Geochimica et Cosmochimica Acta 70 (19), 4889-4905. http://dx.doi.org/10.1016/j.gca.2006.07.026
Lefticariu, L., Pratt, L. M., LaVerne, J.A., and Ripley, E. M. (2006) Radiolytic oxidation of pyrite: a viable mechanism for sulfate production on Mars? In Workshop on Martian Sulfates as Recorders of Atmospheric -Fluid-Rock Interactions, p. 73-76. LPI Contributions No. 1331, Lunar and Planetary Institute, Houston. http://www.lpi.usra.edu/meetings/sulfates2006/
Lefticariu, L., Pratt, L. M., Eng, P. J., Gose, S. K., and Bish D. L. (2006) Interaction of radiolytically produced oxidants with the pyrite surface: a Crystal Truncation Rod (CTR) study. Lunar and Planetary Science, vol. XXXVII, 2167-2168. http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2167.pdf
Lefticariu, L., Pratt, L. M., LaVerne, J A., and Ripley E. M. (2006) Experimental study of radiolytic oxidation of pyrite: implications for Mars relevant crustal processes. Lunar and Planetary Science, vol. XXXVII, 1953-1954. http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1953.pdf
|Lefticariu, M., Perry, E. C., Ward, W., and Lefticariu L.(2006) Post-Chicxulub depositional and diagenetic history of the northwestern Yucatan Peninsula, Mexico. Sedimentary Geology, 183(1-2), 51-69. http://dx.doi.org/10.1016/j.sedgeo.2005.09.008
Lefticariu, L., Perry, E. C., Fischer, M. P., and Banner, J. (2005) Evolution of fluid compartmentalization in a detachment fold complex. Geology, 33(1), 69-72. http://dx.doi.org/10.1130/G20592.1
Lefticariu, L. (2004) Geochemical constraints on the evolution of the fluid-rock system in the salt-detached Nuncios Fold Complex, Mexico. Ph. D. Dissertation, Northern Illinois University, DeKalb Il, 385 pg.