Acquisition of microscope and automated stage system for fission-track analysis

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This award provides the Department of Geosciences at the University of Arizona with the laboratory equipment to carry out fission-track analysis ? a widely applied age dating technique that provides detailed information on the low temperature thermal history of rocks and minerals. The acquisition of this equipment fills a significant gap in the existing geochronological facilities of the department. Of broader significance is that this facility provides a unique in-house capability to obtain multiple ages from single mineral grains (as small as grains of sand) using the complementary techniques of uranium-lead, fission-track, and uranium-thorium-helium dating. Uranium-lead dating provides the age of formation of the particular mineral being analyzed, while fission-track and uranium-thorium-helium dating provide the time that particular mineral cooled through temperatures below about 250 degrees Celsius to 60 degrees Celsius. Knowing the timing and rates of cooling below the latter temperatures is particularly useful as it provides information of rates and timing of erosion, and by proxy, unique information on, for example, the timing and rates of mountain building processes, landscape formation, and sediment deposition. Such "triple-dating" has unique and innovative potential applications in fields such as understanding glacial processes in Antarctica, evaluating interactions involving climate, climate change and mountain building, to providing valuable new information on the formation and exploration of oil, gas, and mineral deposits.The potential to perform fission-track analysis benefits a variety of ongoing and future projects at the University of Arizona investigating problems as diverse as sedimentary provenance, modern and ancient orogenic and landscape evolution, identification of wildfire in the geologic record, and the role of late Cenozoic global cooling and glaciation on controlling active mountain building. Furthermore, combining fission-track and uranium-thorium-helium dating with the departmental state-of-the-art laser ablation multi-collector inductively coupled plasma mass-spectrometer for uranium-lead dating allows not only the triple-dating of the commonly-used mineral zircon, but also the analysis of other more analytically complex minerals such as titanite, apatite, and monazite. Fission-track facilities also enhance the infrastructure for research and teaching in the University of Arizona Department of Geosciences. A number of undergraduate and graduate students as well as a few post-docs are working on problems that benefit greatly from the application of the fission-track method. These facilities provide them with the opportunity to gain hands-on experience in learning and applying this methodology. This equipment also forms a vital part of ongoing and planned NSF-funded summer student thermochronology workshops held at the University of Arizona.