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Questions?
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Have questions about electron microprobe analysis? Want to know more about our facility? Send us an e-mail or visit our Contact Us page.
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Research in the Electron Microprobe Laboratory
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With respect to geological research, our microprobe is commonly utilized for igneous, metamorphic, and experimental petrology as well as mineral investigations and geochronology.
In addition to serving the several research groups in the Department of Geology and Geophysics, our lab has done analyses for researchers in various University of Minnesota departments and organizations: Chemical Engineering and Materials Science, Anthropology, Aerospace Engineering and Mechanics, Cell Biology and Neuroanatomy, Mechanical Engineering, Electrical Engineering, Physics, Chemistry, Civil Engineering, Neuroscience, the Institute for Rock Magnetism, the Corrosion Research Center, and the School of Dentistry.
The sample material for these analyses have included metals, alloys, thin films, ceramics, optical fibers, and a wide range of other materials for physics, chemistry, and material sciences. Even human teeth and archaeological material (such as flaked stone, Civil War-era brick from a shipwreck, obsidian, native copper, and buttons from a Minnesota fur-trading outpost) have been analyzed with our electron microprobe.
Our Publications List include some publications and presentations these collaborations have produced.
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Examples of Current and Past Projects
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Below are a few examples of research, both past and present, that has made use of data from our electron microprobe. The projects are simply organized alphabetically by the researcher who submitted the description (not necessarily the principal investigator). This list will be continually growing, and we ask that recent users please submit project descriptions for us to add to this page. Please also e-mail us with any corrections or desired changes.
Graham Baird, Graduate Student
- Monazite dating with electron microprobe analysis: Shear zones, thin tabular zones of high strain are still not completely understood. Things which remain unclear about their genesis are: if volume loss occurs during development in some, none, or all shear zone; how strain varies through interconnecting arrays of shear zones; and the genetic connection between shear zone 3-D geometry to the surrounding fabric and to the larger scale tectonics which give rise to them. Multiple shear zones within the Diana Syenite in the NW Adirondacks and shear zones from the Calendonides of northern Sweden will be studied in hopes to answer the outlined questions.
Peter Davis, Graduate Student
- Investigating the role of deformation in metamorphism
Kristina Gross, Summer Intern
- Zircon zonation patterns as revealed by cathodoluminescence and backscattered electron images: implications for the interpretation of the thermotectonic evolution of Western Labrador; collaborating graduate student: Fawna Korhonen; advising professor: Jim Stout.
Leslie Hasbargen, Adjunct Lecturer
- Diagenetic effects on Uranium-Thorium disequilibrium in old corals; research involved measurement of uranium and thorium isotopes with a thermal ionization mass spectrometer and measurement of major element concentrations with an electron microprobe. Advisor: Larry Edwards.
Qingsong Liu, Graduate Student
- Institute for Rock Magnetism: The grain sizes of different fractions of magnetic extracts from the Chinese loess and paleosol sampls were quantified by obervation with the electron microprobe; this helped us to determine the grain size depenecy of magnetic properties and further link to paleoclimatic signals.
Jessica Oster, Summer Intern
- Trace element variations in a speleothems. Speleothems (cave deposits) are capable of providing high-resolution terrestrial paleoclimate records. They can record paleoclimate data in the form of carbon and oxygen isotope records, radioisotope records, and luminescence banding. Recently, researchers have focused on speleothem trace element records, which have been interpreted to indicate seasonal changes in water residence time in the vadose zone or changes in the dissolution/precipitation processes of the host limestone. Using the electron microprobe, we were able to produce a high resolution, quantitative line transect across optical banding (presumed to be seasonal) from a speleothem from Crevice Cave, Missouri. Advisor: Larry Edwards
Kathryn Stalker, Summer Intern
- Examination of carbonate melt and the relationship between carbonate and silicate melt in mantle conditions through high pressure and temperature experiments. In the Experimental Petrology Laboratory, I used a piston cylinder machine to expose various samples of rock or carbonate to mantle condition pressures and temperatures and then analyzed the different run products, such as quenched dolomitic crystals, with the electron microprobe.
Erik Stoltenberg, Summer Intern
- The role of water in the mantle wedge above subducting lithosphere (at depths of 75-120 km). This project involved high-temperature, high-pressure piston cylinder experiments to create synthetic wet peridotites at 3 GPa pressure and temperatures ranging from 1000 C to 1200 C. The synthetic peridotites were characterized on an electron microprobe. J. Engstrom had recently found an ordered layering phenomenon in the forsterite and enstatite. This type of magmatic layering might be related to the process of layering in some mafic intrusion, developing in shallow magma chambers. Therefore, the process of mechanical compaction (which is believed to be important in igneous layered intrusions) was investigated in the context of the upper mantle. The presence of a thermal gradient, and therefore the presence of a chemical potential gradient, was also hypothesized. A method using the characteristics of a [MgO + Al2O3 spinel] reaction to characterize the nature of the thermal gradient in the sample assembly is also being investigated based on the results of this research. Advisor: Marc Hirschmann.
James Stout, Professor
- Application of electron microprobe techniques to phase equilibria in igneous and metamorphic rocks. Current applications are to oxide-silicate equilibria in Labrador, and to calc-silicate equilibria at different levels in the crust. The latter include granulites from lower crustal rocks from New Zealand and contact skarns around Tertiary intrusives in Colorado.
Donna Whitney, Associate Professor
- Partial Melting and Tectonics: This research involves investigation of the role of partial melting in the tectonic development of orogens, including magmatic arcs (North Cascades) and collisional belts (Turkish segment of the Alpine-Himalayan belt; gneiss domes in the Canadian Cordillera). A current focus is investigating the relationships and feedbacks of decompression, partial melting, and the tectonic/thermal evolution of metamorphic core complexes and gneiss domes.
- Metamorphism and Tectonics in the Eastern Mediterranean: Co-workers and I are studying the pressure-temperature-time history and tectonic development of metamorphic terrains in Turkey. Current work focuses on two regions and problems: the continental margin subduction complex, Sivrihisar region and the thermal evolution of oblique orogens, Nigde region (Central Anatolian Crystalline Complex).
- Partial Melting and Orogeny: Teyssier, Whitney, Fayon, and Kruckenberg; Structure and Tectonics Research Group. This research involves investigation of the role of partial melting in the tectonic development of orogens, including collisional belts and magmatic arcs. A current focus is investigating the processes that lead to decompression of deep crustal rocks without significant cooling, and examination of the thermal/tectonic processes leading to the generation and emplacement of crustally-derived magma.
- Continental Subduction: Teyssier, Whitney, Davis, Aycenk, and Francis; Structure and Tectonics Research Group. We are investigating decompression of subducted continental crust as a possible mechanism for large-magnitude, high-temperature decompression and extensive partial melting in orogens. We are also studying the structural and metamorphic history of the Anatolide-Tauride continental margin in central Turkey, where continental rocks were buried to great depths (blueschist and eclogite facies) in a subduction complex and exhumed during collision.
- Decompression/Exhumation and Cooling Processes: Teyssier, Whitney, Fayon, and Kruckenberg; Structure and Tectonics Research Group. Decompression of deep continental crust may be initiated by processes driven from above (erosion, tectonic denudation) and/or below (crust/lithosphere thinning related to mantle dynamics; buoyancy-driven rise of buried continental crust). The Shuswap metamorphic core complex, British Columbia, is the focus of a current study on the role of fluids in cooling the orogenic crust.
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Content published on this Web Site is copyright the University of Minnesota Regents, the Electron Microprobe Laboratory, and/or the laboratory's users. Some content (particularly analyses and images of specimens) represents the intellectual property of laboratory users. Reproduction or distribution without permission is prohibited. Site content is available for educational and informational uses only, provided that the content is unmodified and that permission is granted by the author and/or the laboratory manager.
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