TEACHING & RESEARCH
Haydn Murray Chair of Applied Clay Mineralogy
- Postdoctoral fellow, 1977-1980, Harvard University
- Ph.D., 1977, Pennsylvania State University
- B.S., 1974, Furman University, High honors
I concentrate on the application of crystal chemical and crystal structural fundamentals to geological, materials, and environmental problems. Much of my recent work has focused on understanding the structures, properties, and origins of fine-grained minerals, such as clay minerals and natural zeolites, using a multidisciplinary approach. For example, in a recent study of kaolinite origin, I focused on an analysis of the degree of crystalline order present within samples using computer simulation of powder diffraction patterns, showing that kaolinite order varies greatly as a function of particle size (some samples showing the best order in the finest fractions). I later combined these studies with trace-element (REE) analyses as a function of size fraction to gain a more complete picture of kaolinite genesis (and also showing that the trace-element content of natural kaolins is attributable mostly to their trace mineral content). My recent studies of the surface properties of smectites were similar, including diffraction, spectroscopic, and surface chemistry analyses. Although fundamental in nature, these surface property studies are of great importance in understanding many applied aspects of smectite behavior, from their ability to swell osmotically, to uses in landfills, to predicting new uses of surface-modified smectites as organic adsorbents. Other applied mineralogical studies include my work on the behavior of fluorine in brick raw materials (clay minerals), the measurement of trace erionite in natural zeolite products, and a variety of studies on the importance of clay and zeolite minerals in radioactive waste applications.
My research often involves powder diffraction methods, including the Rietveld method, a powerful technique that facilitates extraction of a tremendous amount of quantitative information from diffraction patterns of solids. I have clarified the structures of a number of important fine-grained minerals using a combination of X-ray and neutron powder diffraction methods with spectroscopic techniques. For example, I recently elucidated the nature of the interaction of hydrazine, an environmental pollutant, with the mineral kaolinite using diffraction and spectroscopic methods. I have also been a pioneer in the development of the Rietveld quantitative analysis method. This method provides quantitative mineralogic information on fine-grained rocks, with precision comparable to that obtained in X-ray fluorescence analyses. Although I have concentrated on X-ray powder diffraction methods, I also routinely use neutron powder diffraction methods in my research. Neutron diffraction is uniquely suited to studies of hydrous minerals such as clays and zeolites. Unlike X-ray diffraction that is insensitive to H atoms, neutrons are strongly diffracted by H atoms, allowing determination of quantitative information on the conformation of H, particularly OH, in minerals. This is quite important because OH groups and water molecules determine much about a mineral’s behavior. For example, it is the conformation of interlayer H atoms in kaolinite (and in clay minerals in general) that determines the interlayer stacking and how strongly the layers are held together. I participate in the neutron diffraction community, and I understand that the IU Cyclotron Facility is proposing to build a university-based pulsed neutron source at IU. Such a facility would be quite valuable as both a research tool for the study of minerals and as an educational tool, to illustrate the multidisciplinary nature of materials studies.
I am also particularly interested in the study of minerals under controlled–T, –P(H2O) conditions. Such experiments routinely provide new insights into the structures and behavior of materials that analyses under room conditions do not provide. These experiments are particularly important in understanding and predicting applications of minerals under real-world conditions because many minerals are used under conditions quite distinct from typical laboratory conditions of T and
P(H2O). An example of these studies is my research on the thermal and sorptive behavior of minerals at the potential high-level radioactive waste repository at Yucca Mountain, Nevada. This work included X-ray diffraction under non-ambient conditions and emphasized the effects of long-term heating of a variety of minerals, including clays and zeolites. I recently combined this research with thermodynamic modeling to provide insights into the coupled effects of temperature and water vapor pressure on mineral stability.
My experience in experimental studies of minerals under non-ambient conditions has recently been expanded to cover studies of potential martian hydrous minerals. This research initially concentrated on whether or not hydrous zeolites and clay minerals could exist on the martian surface in a hydrated state, thereby partially accounting for the water that has been observed heterogeneously distributed on the present-day martian surface. More recently, I have expanded this research to studies of hydrated salt minerals, including magnesium and iron sulfates. Both of these have either been implicated based on spectroscopic or chemical data or have actually been observed on the martian surface. The magnesium sulfates form a fantastic array of hydrated phases, some of which are undoubtedly stable in a hydrated state on the present-day martian surface. The iron sulfates also exist in a wide variety of hydration states and many different structures and our recent data show that they have very low thermal stabilities. Ongoing studies will assess whether or not they might be stable on the martian surface.
My teaching philosophy combines traditional geology and mineralogy education with my experiences in the more-applied world of Los Alamos National Laboratory, where I worked for 23 years prior to coming to Indiana University. Thus, I feel it is important to provide students not only with the chemical and mineralogical foundations to geological systems, but also to give an appreciation for and experience with real-world problems involving their use. I am excited by both basic and advanced courses in mineralogy, with a focus on fine-grained minerals such as clays and zeolites and on rock-forming minerals. I also find applied courses such as environmental mineralogy, industrial mineralogy, and extraterrestrial mineralogy to be ideal avenues for putting the fundamental chemical and mineralogical foundations to work. In all of my courses I try to consider what I found to be important throughout my career at Los Alamos and, in this way, my teaching is tempered by my real-world (if one can call Los Alamos National Laboratory “real world”) experiences. I will periodically teach advanced courses related to my fields of interest, including X-ray crystallography, powder diffraction, spectroscopy, and thermal analysis.
Recent Research Projects
- Development of a miniaturized X-ray diffraction/X-ray fluorescence instrument for planetary exploration (CHEMIN).
- Studies of the stability of possible martian hydrous minerals under simulated Mars surface conditions.
- Quantification of the surface properties of clay minerals and implications for their use in environmental applications.
- Use of X-ray powder diffraction in quantifying mineral abundances.
- Application of the Rietveld method to determining quantitative crystal structural information from fine-grained minerals using X-ray powder diffraction data.
Awards and Honors
- Secretary-Treasurer, International Natural Zeolite Association, 2014-
- UNESCO and IUCr International Year of Crystallography-2014 inaugural session plenary lecturer, UNESCO Headquarters, Paris, France, January, 2014
- Vice-president, Mineralogical Society of America, 2009-2010
- Participating Scientist, Mars Phoenix Lander, 2008-
- George Brown Lecture Award of the Clay Minerals Group, Mineralogical Society of Great Britain, 2007
- Ralph Grim Lecturer, University of Illinois, March, 2007
- President, International Association for the Study of Clays (AIPEA), 2005-2009
- Brindley Lecture Award, The Clay Minerals Society, 2002.
- Co-recipient of a 1999 R&D100 Award for "CHEMIN: A Miniaturized X-ray Diffraction and X-ray Fluorescence Instrument"
- Jackson Clay Scientist Award, The Clay Minerals Society, 1995
- Fellow, Mineralogical Society of America, 1990-present
- Graduate Studies Committee, Indiana University Department of Geological Sciences
- Member, Policy Committee, Indiana University Department of Geological Sciences
- Member, Undergraduate Honors Advisor, Indiana University Department of Geological Sciences
- President, International Natural Zeolite Association, 2002-2006
- President, International Committee on Natural Zeolites, 2002-2006
- Member of Council, Mineralogical Society of America, 1999-2002
- President, The Clay Minerals Society, 1998-1999
- Vice-president, The Clay Minerals Society, 1997-1998
- Board Member, International Committee on Natural Zeolites, 1997-present
- Mineralogical Society of America National University Lecturer, 1997-1998
- Associate Editor, Zeitschrift für Kristallographie, 1996-1999
- Associate Editor, Clays and Clay Minerals, 1993-1996, 2002-2003
- Associate Editor, American Mineralogist, 1987-1991, 2002