Department of Earth SciencesWestern Science

Dr. Roberta Flemming

Mineralogy

Roberta FlemmingAssociate Professor
Ph.D. Queen's University, 1997
Office: BGS 0172
Phone: (519) 661-3143
Fax: (519) 661-3198
Email: rflemmin@uwo.ca

Research Interests

Professor Roberta Flemming and her research group study a variety of mineralogical and geological problems using a combination of crystallography, mineral chemistry and spectroscopy. Observations made from synthetic minerals produced at high temperatures and pressures in the laboratory, and from natural minerals found in Earth and planetary materials, are used to understand changes in mineral structure, chemistry, cation distribution, solid-solubility, and phase transition behaviour in response to changes in pressure, temperature, and composition (P-T-X), on Earth and other planetary bodies.

Flemming employs a variety of techniques, including X-ray diffraction and microdiffraction, Rietveld refinement of diffraction data, electron probe microanalysis (EPMA), and a variety of spectroscopic techniques, including solid-state nuclear magnetic resonance (NMR). Flemming’s current research objectives are outlined below:

  1. Fundamental understanding and quantification of mineral behavior as a function of pressure (P), temperature (T) and composition (X) by synthesizing minerals at various P-T-X, and studying their crystal structure (X-ray diffraction/Rietveld refinement), crystal chemistry (EPMA), and cation order-disorder (NMR spectroscopy, e.g. 29Si, 27Al, , 17O). 
  2. Systematic mineralogical investigation of meteorites. In situ µXRD provides rapid mineral ID for meteorite classification and clues to thermal and shock history. In situ µXRD also provides shock stage quantification, as a function of strain related mosaicity (streaking or asterism along Debye rings).  Rietveld refinement of powder XRD data provides modal mineral analysis, and enables crystal structural study of selected phases.
  3. Systematic investigation of Kimberlite Indicator Minerals (KIM) (e.g. garnet, chromite, Cr-diopside). Variation in unit cell parameters (µXRD) is correlated to geochemical data (EPMA) with the aim of developing µXRD as a tool for diamond exploration. Inclusions and strain related mosaicity in minerals give additional clues to origin.
  4. Development of micro X-ray diffraction (µXRD) as a tool for geologists. µXRD provides a unique opportunity to correlate crystal structural information with other microanalytical data on the microscopic scale (100-300 µm) not previously available.  In situ examination of minerals preserves orientational information. Anticipated projects include development of µXRD-related exsolution geothermometry (e.g. two pyroxenes), and quantification of strain-related mosaicity in minerals in meteorites, impact structures, and tectonically deformed rocks, with the aim of developing a µXRD strain index.

Selected Publications

Courses Taught

Undergraduate courses (currently taught):
Earth Sciences 2206a: Mineral Systems, Crystallography and Optics
Earth Sciences 2212b: Genesis of Meteorites and Planetary Materials (even years)
Earth Sciences 3310b: Structure and Chemistry of Minerals and Materials (odd years)

Undergraduate courses (previously taught):
Environmental Science 300F: Great Lakes Pollution (2001, 2002)
Earth Sciences 3341b: Environmental Geochemistry (2003)

Graduate Courses:
Geology/Geophysics 9580a/9680a: Graduate Seminar (2005, 2007, 2008, 2009, 2010, 2012)
Geology 9516b: Advanced Mineralogy and Crystallography (2002, 2004, 2006, 2008, 2010, 2012)
Geology 9549a/b: Special Topics in Mineralogy (2005, 2012)

Students

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Former:

Available projects include: