Further development of redox-sensitive metal isotopes as tracers for sedimentary systems

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Redox-sensitive metal isotope systems are emerging as powerful tools to address fundamental questions in evolution and major societal challenges such as securing sufficient mineral and energy resources to sustain an increasingly advanced technological society while simultaneously protecting the environment. Over the next five years, Dr. Kendall's group will further develop and apply established and innovative redox-sensitive metal isotope systems (molybdenum, uranium, thallium) as tracers for modern and ancient sedimentary systems. Coupled molybdenum-uranium-thallium isotope data and metal concentration data from organic-rich sedimentary rocks represents a novel approach for tracking changes in the extent of ocean oxygenation through time in a more quantitative manner using innovative mathematical models. Analysis of a global set of middle Proterozoic to Devonian sedimentary rocks (1,850 to 360 million years ago) will provide new insights on the relative importance of permissible environmental conditions versus genetic and ecological factors on the timing of initial animal diversification on Earth and on patterns of animal evolution in the Paleozoic Era. To help accomplish this objective, modern lakes in northwestern Ontario (Experimental Lakes Area) that represent a modern analogue for early Earth ocean chemistry will be studied to better understand metal isotope behavior associated with metal removal from anoxic and iron-rich waters to organic-rich sediments. This aspect of the research will also study changes to the lakes during the proliferation of harmful cyanobacterial algal blooms and thus will inform strategies for environmental protection and remediation. Coupled molybdenum-uranium-thallium isotope data from hydrothermally unaltered and altered organic-rich sedimentary rocks as well as rocks deposited simultaneously with hydrothermal activity in the world-class Brooks Range lead-zinc-silver district (Alaska) will help better understand the formation of sediment-hosted lead-zinc mineralization, which will aid exploration companies with finding new ore deposits.   It is critical to Canada's economic and environmental future that there is sufficient expertise to handle scientific challenges regarding exploration/exploitation of natural resources and protection/remediation of the environment. Dr. Kendall's Metal Isotope Geochemistry Laboratory at Waterloo offers graduate students a high-quality research training environment. Analytical skills acquired by graduate students will be in high demand because research in metal isotope geochemistry is rapidly expanding in all aspects of the Earth, environmental, and planetary sciences. Hence, the graduate students involved in the proposed research program will have a skill set that will be attractive for employment in Canadian academic institutions, government research organizations, and industry positions related to natural resources, environment, medical geology, and analytical chemistry.