Automated analyses of the sizes and shapes of sedimentary particles can be used in powerful ways to understand how dust preserves in Earth's deep geological record, to test controversial hypotheses of glaciation during deep geological time, document how weathering in modern river systems in different climates may be used to develop quantitative reconstructions of ancient climates, and to document how sediment accumulation linked to human-induced landscape changes may modify modern lake basins. These research projects are unified by their focus on exploring how sedimentary systems inform our understanding of climate change and landscape change, and will be pursued by researchers at the University of Oklahoma using a laser particle size analysis system funded by this award. These projects involve collaboration with, e.g., geochemists and climate modelers, who rely on information from sediment inputs to furthering our understanding. Acquisition of state-of-the-art particle size- and imaging analysis capabilities will expose students, post-doctoral scientists and faculty researchers in geology, allied sciences, and engineering to expanded capabilities in various research endeavors. Undergraduate and graduate students will be exposed to the instrumentation through thesis-related work. Students will be trained on the instrument and gain hands-on experience in acquiring, analyzing, and interpreting their own data independently. The researchers and colleagues will integrate student use of this new equipment, as well as research results enabled by it, in coursework at University of Oklahoma, in undergraduate and graduate classes. Finally, to maximize the effects of this instrument acquisition on broadening participation of underrepresented groups in experiential learning with state-of-the-art analytical tools, the instrumentation will be used by participants in a STEM-based summer camp for minority middle school students, and an in-service teacher professional development training workshop for middle school science teachers.
Specifically, this award funds the acquisition of a laser particle size analyzer (LPSA) and image analysis system for sedimentary geology, paleoclimatology, and other applications at the University of Oklahoma. The LPSA will accelerate and extend the researchers' capabilities by replacing an obsolete instrument that is unserviceable. LPSA assesses grain size using laser diffraction, wherein light scatter induced by particles in a fluid produces a volume-percent size distribution. This is a rapid and time-tested means to measure a range of sizes simultaneously, and is particularly useful for geologic materials of <1-3000(+) ìm. Instruments for automated grain shape analysis are an emerging capability, and employ a high-end microscope system enabling imaging of individual particles (dry or wet dispersions), including shape characterization and detection of aggregates. Quantitative data are captured on 100s-1000s of particles rapidly, including transparency as well as shape attributes. Particle size and shape analysis is non-destructive, and will enable rapid progress on an array of current and planned geological research at University of Oklahoma. These projects include analyses of: 1) the silicate mineral fraction (atmospheric dust) extracted from Upper Paleozoic limestone, to constrain atmospheric circulation (including monsoonal circulation), and biogeochemical effects of aerosols, 2) suspected ice-contact and proglacial deposits to test the controversial hypothesis of upland glaciation in tropical Pangaea, 3) modern fluvial sediments from end-member climates to assess climate controls on physical and chemical weathering (for proxy development), 4) disaggregated Permian redbeds to assess the hypothesis of widespread deposition of loess during the late Paleozoic, and 5) modern lacustrine sediments from Lake Tanganyika (Africa) to assess impacts of land-use changes on sedimentation in littoral regions.
