Physical and chemical characterization of zoned minerals as a measure of environmental change

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Zoning in minerals occurs on a variety of length-scales in many environments, as minerals take time to grow, this zoning records changes in the environment over time. Zoning patterns may be interpreted as (i) driven by external forcing, with evidence of chemical disequilibrium or (ii) self-organization with micron-scale oscillatory zoning, here trace elements are particularly sensitive to environmental change. This research will quantify rates and extent of environmental change using zoned mineral chemistry in near surface environments. Otoliths, ear bones of bony fish, will be used as a tool for i) monitoring the affects of mine tailings on aquatic organisms and environments, and ii) assessing migratory behaviour in fish; and an examination of the physical and chemical controls of mineral growth in ice. Incremental structures in biominerals can be used to establish background chemical/trace element levels in aqueous environments, and monitor environmental change. The scale and rate of response of the biomineral to externally driven environmental change is largely unknown, and the biomineral is often "buffered" by the metabolism of the organism. Metabolic transformation of trace elements makes their use as temporal markers of contaminant uptake tenuous. The advantage of otoliths is that they are metabolically inert, retaining a complete record of chemical exposure over several years to decades. Research is planned in four areas: 1) otolith microchemistry focusing on Sr, Ba and Mn, Hg & Se in otoliths; 2) stable isotope analysis of otoliths from migratory fish species to assess the extent of trace element uptake connected with organic carbon (food sources; 3) trace element analysis of synthetic CaCO3 and 4) trace element characterization of carbonate minerals from sea ice. Zoning patterns will be analyzed by fs-NIR-LA-ICP-MS and SIMS. Mining operations require water for processing and/or tailings storage so resource extraction and conservation are often seen as competing interests. Data from this research will inform land use decisions and fish management practices crucial to planning in northern Canada as mineral exploration and global warming proceed.