The NSERC USRA (Undergraduate Student Research Award) is a paid summer research fellowship lasting 16 weeks. USRA's are meant to stimulate your interest in research in the natural sciences and engineering. They are also meant to encourage you to undertake graduate studies and pursue a research career in these fields. If you would like to gain research work experience that complements your studies in an academic setting, these awards can provide you with financial support through Western.
Who can apply: Canadian citizens or permanent residents in 2nd, 3rd, or 4th year. You must be a full time student with >80.0% cumulative average as of Aug 31, 2013. You do not have to be a Western student to apply.
How to apply:
Earth Sciences Deadline: Wednesday January 15, 2014 at 4:00 PM.
The NSERC USRA summer student will study the variation in cation order-disorder for single chain silicate pyroxenes, M2[M1]T2O6, as a function of composition, across several solid solution series (e.g. aluminous diopside, Ca[Mg,Al](Si,Al)2O6, and Sc-Ti-In substituted compounds, Ca[Sc,Ti](AlSi)2O6 and Na[In,Sc]Si2O6, and naturally-occurring aluminous pyroxenes) using a combination of X-ray diffraction (XRD) and 29Si and 27Al solid state Nuclear Magnetic Resonance (NMR) spectroscopy.
NMR spectroscopy is a local probe of cation substitution around the nucleus of interest and can be used to measure cation order-disorder. Cation order-disorder in these minerals is an indicator or formation temperature. Peak positions in 29Si NMR spectra of pyroxene are sensitive to both tetrahedral and octahedral cation substitution. 27Al NMR is a sensitive indicator of site distortion.
Time permitting, the student will also synthesize diopside-TiCaTs (CaMgSi2O6- CaTiAl2O6) solid solutions by a two stage process: High temperature synthesis of stoichiometric glass (Flemming’s mineralogy lab) followed by high pressure mineral synthesis in a multianvil apparatus (Secco’s lab). They will characterize these materials by XRD and solid state NMR spectroscopy.
Minerals subjected to stress, such as by tectonic forces during regional metamorphism or shock metamorphism during meteorite impact, exhibit deformation by inhomogeneous or plastic strain (e.g. bending). Inhomogeneous or plastic strain can produce two effects in 2-dimensional X-ray diffraction patterns: (1) increasing mosaic spread as seen by streaking in the chi dimension, and (2) inherent strain, as seen by line broadening of the X-ray diffraction peak in the 2theta dimension. The Bruker D8 Discover micro X-ray diffractometer, with a two-dimensional general area diffraction detector system (GADDS), can be used to make in situ observations of both mosaic spread (FWHM) and inherent strain (peak FWHM2θ) in minerals and quantify these parameters as a function of degree of strain/shock experienced by the specimen.
The NSERC USRA student will observe strain in selected minerals in terrestrial rocks and meteorites, using optical microscopy and microXRD, and will correlate FWHM against FWHM2θ and other parameters. Time permitting, the student will complement these data with observations from SEM/EBSD imaging of selected samples.
The NSERC USRA student will study a variety of unclassified meteorites using optical microscopy, micro X-ray diffraction (XRD), and Electron Probe Microanalysis (EPMA) (on selected samples), in order to classify their petrologic type (thermal metamorphic grade), shock metamorphism and weathering stage. From XRD data, the student will identify metal, oxide, sulfide, and silicate mineral phases by their crystal structures, using the International Centre for Diffraction Data (ICDD) database, and combine this information with optical and EPMA observations to classify the meteorite. For selected minerals (e.g. olivine) the student will correlate unit cell dimensions with composition and make quantitative strain measurements, to determine shock stage. In addition, the student will investigate interesting phenomena in a variety of meteorites, such as shock veining to search for high pressure minerals, or aqueous alteration reactions to determine formation conditions. This work will be done in collaboration with meteorite curator Dr. Phil McCausland.
Glacial meltwater escaping from Lake Agassiz, other proglacial lakes, and/or the Laurentide Ice Sheet has been strongly implicated in triggering the global Younger Dryas cold spell between ~13,000 and 11,500 cal years BP. Key questions remain concerning the pathway(s) travelled by this glacial meltwater on its way to the Atlantic Ocean – with northwestern routes (via the McKenzie River Valley to the Arctic Ocean), northeastern routes (via Hudson’s Bay) and eastern routes (through the Great Lakes) all gaining favour at one time or another. We will use the stable isotopic compositions of flora and shelly fauna (oxygen- and carbon-isotope compositions of carbonate, carbon- and nitrogen-isotope compositions of organic matter) to evaluate the eastern route hypothesis. We will calibrate the meltwater signal by analysis of climate proxies preserved sediments from Georgian Bay and nearby small lakes.
Working with already-collected lake cores plus participation in May-August 2013 coring and sampling, the student will be responsible for the isolation, identification and stable isotopic analysis of the various faunal and floral materials found in the cores and collected in the field, preliminary interpretation of the data collected, and preparation of a report summarizing the results.
Late Pleistocene and Holocene sediments of the Great Lakes Basin contain many proxies for climate change in this region over the last ~15,000 cal years BP. As a companion to ongoing stable isotopic studies of sediments from Lakes Superior, Michigan, Huron, Ontario and Erie, we will examine similar proxies for climate change contained in sediments from a small sinkhole lake (Barry Lake) located near Peterborough, Ontario, and a small pond (Carolinian Pond) contained in Pinery Provincial Park, Lake Huron, Ontario. Our focus will be on sediments recording climate changes spanning the warming period known as the Holocene Hypsithermal, the later cooling known as the Holocene Neoglacial interval, and the climate patterns over the last 500 years, including warming over the last ~100 years.
Working with already-collected gravity sediment cores from Barry Lake, and through participation in May-June 2013 sediment coring expeditions to the Carolinian Pond and similar water bodies, the student will be responsible for the isolation, identification and stable isotopic analysis of the various faunal and floral materials found in the cores, preliminary interpretation of the data collected, and preparation of a report summarizing the results.
One curious aspect of some Pleistocene megafauna (mammoths, horses) is their strong tendency to be enriched in nitrogen-15 relative to the typical ratio of 15N/14N found in herbivores, except during the latest Pleistocene. Several hypotheses have been offered to explain this unusual result, including climate-related dynamics in the ‘Mammoth Steppe’ ecosystem, physiological behaviours causing nitrogen recycling within the bodies of these large animals, and coprophagy. We will test the hypothesis that these megafauna consumed 15N-enriched plants that thrived in their habitat – as a consequence of aridity, dung fertilization and related processes in this now extinct soil-plant-animal ecosystem. The hypothesis will be explored through study of modern elephant and cattle pastures, and then extended to a suitable Pleistocene site where analysis of paleobotanical materials located in context with mammoth and horse remains is possible. We will also explore possible reasons for the sudden lowering of nitrogen-15 concentrations in the tissues of these megafauna at the end of the Pleistocene, testing in particular the idea that this dramatic change arose from fundamental modifications to nitrogen cycling in the soil-plant system because of a major shift in climate.
The student will participate in field work, and be responsible for sample characterization, stable isotopic analysis, preliminary interpretation of the data collected, and preparation of a report summarizing the results.
The permanent magnetic record in rocks such as basalt, limestone and red shale can act like a frozen compass to record the ancient direction to the north pole at the time when the rock formed. This work uses samples from Western Newfoundland and Nova Scotia to estimate the ancient location of North America with respect to the Earth’s polar regions during the early to mid Paleozoic, by laboratory measurements of sample stepwise demagnetization to reveal the ancient magnetic direction. A possible development of this work with Dr. McCausland is to conduct new sampling of similar-aged rocks.
Explore several new meteorites using non-destructive techniques such as X-ray Computed Tomography 3D imaging and related techniques as well as by microscopic examination of meteorites in thin section and electron microprobe analysis of mineral chemistry and textures. This work is anticipated to result in the submission of official descriptive reports for several new meteorites, and can lead to further scientific study of interesting discoveries where warranted. Experience with introductory mineralogy is helpful, but not required.
Before arriving on Earth as meteorites, small rocks in orbit around the sun were exposed to energetic galactic cosmic rays, which left small damage tracks in meteoritic minerals such as olivine, pyroxene, feldspar and apatite. The cosmic ray exposure history for any meteorite can be read from the cosmic ray track record, which decreases with greater depth, providing essential information on the size of the object before it arrived on Earth. This work involves joining the Western’s Curator of meteorites and other researchers in the Meteor Physics group in the etch preparation and measuring of the cosmic ray tracks in minerals, and in helping to develop more automated, digital techniques for collecting the track data. Research on specific meteorites separate from other researchers is planned, leading to reports on their cosmic ray exposure and on methods development. A background in introductory mineralogy and/or introductory physics is useful but not required.
Many fragments of a very primitive, unusual early Solar System meteorite arrived in January, 2000 on the frozen surface of Tagish Lake, northern British Columbia. A large number of specimens from the search that year are now present in Western’s meteorite collection. These Tagish Lake meteorite samples require further careful description and followup study of some unusual features –the project is to assist Dr. McCausland, Western’s Curator of meteorites in this descriptive work and to explore the interesting discoveries in this group of samples, leading to a report of the key features of the Tagish Lake collection and possibly their scientific implications. Experience with introductory mineralogy is helpful, but not required.
During repeated visits to the Ottawa Valley for undergraduate and graduate field schools, a series of seismic refraction and reflection profiles have been carried out. These surveys provide structural information and rock properties for the Leda clay and its unconformable relationship to the underlying Ordovician limestones. Leda Clays are prone to liquefaction and present a geohazard in the region. The seismic data reveal the mechanical properties of the Leda clay through the seismic P-wave and S-wave arrivals. The data also allow imaging of the clay-limestone interface.
This proposed summer project will involve the re-processing of some of the many profiles we have collected on location in order to shed light on the geophysical and geotechnical nature of the Leda clay. Although some limited processing has been carried out as a part of these field schools, the data have not yet been professionally processed. The data will be reprocessed using professional processing packages; both Promax (TM) and Vista (TM) are available. Training will be provided on the use of these software packages, which are widely used in industry. It is expected that the student will develop a full workflow, from data download to final product. They will further be responsible for documenting this workflow for future use, and writing a publication-quality final report with a view to presentation at a scientific conference.
Impact cratering is the most ubiquitous geologic process in the solar system and, thereby, played a significant role in the early formation, modification and in some cases the aqueous alteration of planetary crusts. Mounting evidence supports that impact cratering played a significant role in the evolution of early life on the Earth and possibly Mars. Impact craters are relatively consistent in morphology making them one of the most easily recognized features on planetary surfaces. Thereby, they are also useful as “probes” and “gauges” of the target properties, and geologic processes that modify planetary surfaces, respectively. In addition, pristine craters offer us a glimpse of the relatively unmodified primary crater deposits, providing insights into the impact cratering process itself, and potentially paleo-environments on planetary bodies with atmospheres and target volatiles (e.g., water).
The long-term goals of my research program are to, 1) improve our understanding of the impact cratering process as a geologic process, and 2) learn about the geological history of upper crust and surface of Mars through remote sensing studies of its most ubiquitous landform – impact craters. My research aims to achieve these goals via four objectives involving the analysis and interpretation of orbital spectral, visible, thermophysical and elevation data sets of the Martian surface.