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M.Sc. or Ph.D. candidates |
Name: Roberta L. Flemming, Assistant Professor Email: Organization: University of Western Ontario Date: 02 Apr 2002 Time: 16:16:21 Job_Description: Dr. Roberta Flemming at the Department of Earth Sciences at University of Western Ontario has four openings for M.Sc. or Ph.D. candidates interested in pursuing fundamental or applied studies of minerals in the following areas: 1. Fundamental understanding and quantification of mineral behavior as a function of pressure (P), temperature (T) and composition (X). Projects will involve mineral synthesis (at high PT), and determination of crystal structure (by X-ray diffraction/Rietveld refinement), crystal chemistry (by EPMA), and cation ordering (X-ray diffraction and NMR give long-range and short-range cation ordering information, respectively). 29Si NMR provides a measure of Si/Al disorder in aluminosilicates, which cannot be discerned by X-ray methods. Aluminous pyroxenes are the subject of ongoing research (Am. Min. 87:25, 2002). A wide variety of other minerals are also of interest. 2. Development of minerals as geothermobarometers, or indicators of T and P of rock formation, through the systematic variation of their chemical and crystallographic parameters. Cation partitioning between minerals, and cation ordering within minerals, are both functions of P-T-X. Understanding the relationship between intercrystalline and intracrystalline cation distributions will help us to understand the thermal history of important rock types such as eclogites, peridotites, kimberlites, carbonatites, and ultra-high-pressure metamorphic rocks. Currently of interest are garnet-clinopyroxene equilibria, olivine-spinel equilibria, two-pyroxene systems, and exsolution phenomena. 3. Development of X-ray diffraction/Rietveld modal analysis as a tool for geologists. At present, X-ray diffraction is underutilized in the areas of mineral exploration and mineral processing. This pilot project will involve testing X-ray diffraction/Rietveld modal analysis as a tool for monitoring mineral extraction methods, using samples provided by participating Canadian industries. 4. Development of X-ray microdiffraction as a tool for geologists. A CFI-funded microdiffractometer will provide a unique opportunity to correlate crystal structural information with chemical and spectroscopic data on a grain-by-grain basis, on a microscopic scale (30-50 um) not previously available routinely. A variety of projects are envisaged, such as X-ray identification of ~{!.~}diamond indicator minerals~{!/~} (e.g. G-10 garnet) by correlation of diffraction data to geochemical data. Facilities available at UWO include a Bruker DISCOVER X-ray diffractometer- microdiffractometer with 2D area detector and videomicroscope (Flemming CFI- arriving in May 2002), Varian 400 MHz solid-state NMR spectrometer (Chemistry), two high-T synthesis laboratories (Flemming and Fleet), two high-pressure laboratories (King and Secco), as well as EPMA, FTIR, and XRF facilities in Earth Sciences, and XPS, AFM, SEM and SIMS facilities at Surface Science Western. If you wish to obtain more information about these projects, or other possible projects, please contact Dr. Roberta Flemming (519-661-3143, rflemmin@uwo.ca). Collaborative projects with other faculty members are also possible. Research and teaching assistantships are guaranteed for qualified students. Additional information can be obtained by visiting the Department of Earth Sciences website at http://www.uwo.ca/earth. Roberta L. Flemming, Assistant Professor Department of Earth Sciences University of Western Ontario Biology and Geology Building London, Ontario, N6A 5B7 Phone: 519-661-3143 Fax: 519-661-3198 |
消息来源 Dr. Roberta Flemming 4/2/2002 |