Technician support for geoscience research in transmission electron microscopy

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EAR-0418960BuseckThis Phase II proposal is to support a full-time specialist in electron microscopy to help us take maximum geological, mineralogical, and geochemical advantage of two new state-of-the-art TEMs that were recently installed at Arizona State University. They will allow coupled elemental, crystal-chemical, and structural information to be obtained at the nanoscale. Biosphere-geosphere interactions either influence or lie at the heart of many fundamental questions confronting modern society. These include the origins of life, the habitability of planets, environmental degradation and remediation, climate change, and the geochemical cycling of elements. Carbon is, of course, central to biogeochemistry, and knowledge of the structure and physical-chemical properties of organic C-bearing materials in nature is basic for a mechanistic understanding of biogeochemical processes and other terrestrial and extraterrestrial interactions of C at low to moderate temperatures. These properties are both complex and heterogeneous at extremely short length scales. Characterization of C-bearing materials in terms of external form and internal structure, compositional variability, and bonding properties is not only well-suited to, but in many cases demands, study by TEM and associated spectroscopic techniques able to probe at the nanometer spatial scale. The major focus during Phase II will be on the characterization of carbonaceous materials in three areas of importance to biogeochemistry and C-cycle research: organic matter and other forms of C associated with clays in sedimentary rocks, carbonaceous atmospheric particles, and C in the fine grained matrices of primitive meteorites. In addition, we propose to develop TEM-based techniques for semi-quantitative analysis of H in organic materials on the nanometer scale. A wide range of ongoing projects on high-resolution microscopy of minerals, natural and generated aerosol particles, and controlled environmental TEM studies will also be facilitated through the availability of the senior technician to be provided via the requested grant.***