Dr. Roberta Flemming

Mineralogy

Roberta Flemming

Associate Professor
Ph.D. Queen's University, 1997
Office: BGS 0172
Labs: BGS 1062, 1063
Phone: (519) 661-3143
Fax: (519) 661-3198
Email:
rflemmin@uwo.ca
Lab Website


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 (MAS and MQ MAS NMR spectroscopy: e.g. 29Si, 27Al, 17O, 23Na, 45Sc, etc.). 
  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, measured as FWHMc).  Rietveld refinement of powder XRD data provides modal mineral abundances, and enables crystal structural study of selected phases.
  3. Systematic investigation of Kimberlite Indicator Minerals (KIM) (e.g. garnet, chromite, ilmenite). 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 (FWHMc) in minerals in meteorites, impact structures, and tectonically deformed rocks, with the aim of developing a µXRD strain index.

Selected Publications

  • Berger, J.A., Schmidt, M.E. , Gellert, R., Campbell, J.L., King, P.L., Flemming, R.L., Pradler, I., Thompson, L.M., van Bommel, S.J.V., Boyd, N.I., Perrett, G.M., Elliott, B.E., Fisk, M., and Yen, A. (2016) A global Mars dust composition refined by the alpha-particle X-ray spectrometer in Gale Crater. Geophysical Research Letters. Online Jan 9, 2016, DOI: 10.1002/2015GL066675.
  • Craig, M.A., Osinski, G.R., Cloutis, E.A., Flemming, R. L., Izawa, M.R.M., Reddy, V., Fieber-Beyer, S.K., Pompilio, L., van der Meer, F., Berger, J.A., Bramble, M.S., and Applin, D.M. (2016) Fitting the curve in Excel®: Systematic curve fitting of laboratory and remotely sensed planetary spectra. Computers and Geosciences, in press November 2016.
  • Bramble, M.S., Flemming, R.L., and McCausland, P.J.A. (2015) Grain size measurement from two-dimensional micro-X-ray diffraction: Laboratory application of a radial integration technique. American Mineralogist, 100 (8-9): 1899-1911. (Aug-Sept 2015)
  • Flemming, R.L., Terskikh, V. and Ye, E. (2015) Aluminum environments in synthetic Ca-Tschermak clinopyroxene (CaAlAlSiO6) from Rietveld refinement, 27Al NMR and first principles calculations. American Mineralogist, 100 (10): 2219-2230. (Oct 2015)
  • McNeil, A.G., Linnen, R.L., and Flemming, R.L. (2015) A method for hydrothermal synthesis of columbite-(Mn), tantalite-(Mn), hafnon and zircon at 800°-850°C and 200 MPa. Canadian Mineralogist, 53, 1073-1081. DOI: 10.3749/canmin.1400077
  • Pickersgill, A.E., Flemming, R.L. and Osinski, G.R. (2015a) Toward quantification of strain-related mosaicity in shocked lunar and terrestrial plagioclase by in situ micro-X-ray diffraction. Meteoritics & Planetary Science, 50 (11): 1851-1862.
  • Pickersgill A.E., Osinski, G.R. and Flemming, R.L. (2015b) Shock effects in plagioclase feldspar from the Mistastin Lake impact structure, Canada. Meteoritics & Planetary Science. 50 (9): 1546–1561.
  • Bramble, M.S., Flemming, R.L., Hutter, J.L., Battler, M.M., Osinski, G.R., and Banerjee, N.R. (2014) A temperature-controlled sample stage for in situ micro-X-ray diffraction: Application to Mars analogue mirabilite-bearing perennial cold spring precipitate mineralogy.  American Mineralogist, 99: 943-947.
  • Libbey, R.B., Longstaffe, F.J. and Flemming, R.L. (2013) Clay mineralogy, oxygen isotope geochemistry and water/rock estimates, Te Mihi area, Wairakei Geothermal Field, New Zealand. Clays and Clay Minerals, 61 (3): 204-217.
  • McCausland, P.J.A., Flemming, R.L., Wilson, G.C., Renaud, J., Dillon, D. and Holdsworth, D.W. (2013) The Wood Lake, Ontario H4 ordinary chondrite, a new Canadian meteorite. Canadian Journal of Earth Sciences, 50(1): 32-43.
  • Izawa, M.R.M., Flemming, R.L., Zhan, R., and Jisuo, J. (2012) Characterization of green clay concretions from the Tonggao Formation, South China: Mineralogy, petrogenesis and paleoenvironmental implications. Canadian Journal of Earth Sciences, 49(9): 1018-1026.
  • Haring, M.M., Flemming, R.L., Terskikh, V., Grossman, L. and Simon, S.B. (2012) Crystal structure and cation ordering in fassaite from Type B CAI TS62B in Allende CV3.  43rd Lunar and Planetary Science Conference, March 19-23, Texas. Abs. # 2601.

Courses 

  • Earth Sciences 2206A: Mineral Systems, Crystallography and Optics
  • Earth Sciences 3310B: Structure and Chemistry of Minerals and Materials 
  • Earth Sciences 3312B: Genesis of Meteorites and Planetary Materials 

Current Students

  • Dylan Langille, MSc Geology Candidate (Co-Supervisor)
  • Yaozhu Li, MSc Geology Candidate (Co-Supervisor)
  • Fengke Cao, PhD Geology PlnSci Candidate 
  • Mitchell Galarneau, MSc Geology Candidate 
  • Victoria Houde, MSc Geology PlnSci Candidate
  • Laura Jenkins, MSc Geology PlnSci Candidate
  • Mallory Metcalf, MSc Geology Candidate 

Future Students

Available projects include:

  • Crystal structure, cation ordering and configurational entropy in aluminous minerals, using NMR spectroscopy and diffraction methods (e.g. Solar system spinel, Al-diopside (‘fassaite’), melilite).
  • Systematic determination of unit cell parameters in KIM minerals (e.g. chromite, ilmenite, Cr-diopside) and investigation of crystal structural – crystal chemical correlations.
  • Mineralogical investigation of meteorites: Crystal chemical clues to formation, thermal and shock metamorphism, aqueous processing, and weathering. Meteorites of interest include chondrites (e.g. Allende, Tagish Lake), achondrites (e.g. ureilites, 4 Vesta HEDs), martian.
  • Systematic determination of unit cell parameters for major minerals in meteorites (e.g. clinopyroxene and olivine) and correlation to mineral chemistry and planetary origin.
  • Quantification of strain-related mosaicity in minerals in meteorites, impact structures, and tectonically deformed rocks, with an aim toward development of a µXRD strain index, and calibration using existing strain indices. (e.g. olivine, pyroxene, plagioclase, quartz, KIMS)
  • Development of µXRD for exsolution geothermometry. (e.g. two pyroxenes). GADDS image provides simultaneous unit cell information (related to composition) for both phases, as well as their T-dependent orientational relationship.