Acquisition of a Scanning Electron Microscope for Earth Science Research and Training of the Next Generation of Geoscientists

Overview: A scanning electron microscope (SEM) is an essential tool for grain-scale textural and chemical characterization of earth materials, which have terrane-scale applications in petrotectonics and other fields. However, in addition to research applications, an SEM can, and should be, as integral a part of the instructional toolkit in earth science training as a petrographic microscope or X-ray diffractometer. We propose to acquire a basic SEM that will be used in NSF-funded research projects that integrate graduate, undergraduate, and high school students and instructors in the research activities of several faculty at UK and nearby universities. The basic SEM will be enhanced with peripheral devices (e.g., SDD energy dispersive spectrometry system, CL detector, motorized stage) that will be acquired with the support of the Kentucky Geological Survey (KGS). The instrument will be maintained by a team of personnel, including the PI, a lab manager in the KGS, and the academic lab coordinator in the Dept. of Earth and Environmental Sciences. Instruction of student users will include the PI and “student-techs”, i.e., graduate and senior undergraduate students who are experienced users of the SEM in their own research. Intellectual Merit: Active NSF funded research projects requiring the use of grain- and subgrain-scale imaging capability include: (1) “Dating Transpression”: models for mid-crustal zones of transpression (ZoT) assume contemporaneity of deformation across and along the ZoT. This project is testing that assumption by dating deformation via zircon U-Pb geochronology in deformed plutons within the ZoT and dating monazite growth tied to deformation microstructures in metapelites within and bounding the ZoT. The geochronology requires imaging of zircon by CL/BSE/SE for U-Pb SIMS geochronology, and BSE imaging/X-ray compositional mapping of monazite for Th-Pb SIMS geochronology and Th-U-Pb chemical age dating via EPMA. (2) “Hot Granites”: exceptionally high-Zr, zircon-rich granites were generated during Grenville orogenesis. Research will model the crystallization history of high-Zr granites and determine Ti-in-zircon temperatures to test whether the granites are in fact “hot” (900-1050oC). This requires characterization of zircon growth zoning, presence of xenocrysts, and inclusion mineralogy via CL/BSE/SE-imaging and EDS. (3) Characterization of minerals analyzed in cosmogenic dating of surficial materials and tephrachronology for neotectonic studies. Other research projects in EES and KGS that will utilize the SEM include organic-rich mudrock and tight sandstone mineralogy/porosity evolution; effects on reservoir porosity/mineralogy of CO2 injection and storage; detrital monazite sedimentary provenance studies; imaging fine-scale morphological features on invertebrate fossils; mineralogy and petrology of pseudotachylyte and retrograde eclogite; and Laurentian crustal evolution. Broader Impacts: In addition to graduate and undergraduate student research training stimulated by acquisition of an SEM, we propose to expand the impact by integrating the SEM into the local high school earth and physical science curriculum. This will be accomplished by creating a training partnership with a group of earth and physical science instructors in the Fayette County Public School System (FCPS), who will receive on-site training in the theory and operation of the SEM during a one week summer workshop. In the following academic year, instructors will utilize the remote access capabilities of the SEM operating system to incorporate imaging and microanalysis into classroom activities, e.g., examination of the nature of earth and biologic materials. The proposed partnership will expand on existing training and research activities between the PI and high school earth science teachers, and has been endorsed by the Director of FCPS K-12 science