| 英文摘要: | The growing evidence for pervasive impacts of humanity on Earth's natural systems makes it critical to assess natural variability in these diverse systems, the extent to which humans perturbed the mean state or extreme ends, and if these perturbations are beyond the systems natural variance. Changes in sediment chemistry reflect changes in physical, biological and anthropogenic processes shaping Earth's surface, recording change in climate, rivers, glacial ice, and ocean conditions and productivity, and humans. This Major Research Instrumentation award funds the acquisition of a high-resolution scanner for rapid, cost-effective and non-destructive analyses of major and trace elemental content of sedimentary records to address this research theme. Next-generation high-resolution scanners measure elemental concentrations from Aluminum to Uranium at high precision and high resolution, and co-register a high-resolution color image of the sample and/or an internal image. These data are collected orders of magnitude faster than traditional wet-chemistry and imaging approaches (hours vs. weeks-months), and the high resolution of scanning is impossible to achieve by physical sampling. This rapidity of data acquisition via next generation high resolution scanning at otherwise impossible resolutions opens new doors for tackling questions of Earth's natural systems behaviors over their full dynamic range including human impacts. The acquisition of a high-resolution elemental scanner and its pairing with the Oregon State University-Marine Geology Repository will have an immediate broad impact on the Pacific Northwest research community where this instrument is greatly needed, and service will extend to national and international research communities. The instrument will enhance at least 10 courses with for experiential learning, and train graduate and undergraduate students in data-intensive geochemical studies. The scanner will promote diversity in Earth sciences through its use of Research Experience for Undergraduates and Increasing Diversity in Earth Sciences programs, coaching underrepresented groups in state-of-the-art studies of Earth's natural systems.
Researchers at Oregon State and the College of Earth, Ocean, and Atmospheric Sciences (CEOAS) will use rapid, high-resolution, and accurate measurements of geochemical changes in sedimentary records to track variations in Earth's natural systems from sediment source to sink. A next-generation X-ray fluorescence (XRF) scanner purchased with this award will be an essential tool for the study of sedimentary geochemical archives of Earth system processes. OSU's acquisition of an XRF scanner would be the first such instrument in the Pacific Northwest, significantly advancing scientific exploration. CEOAS has extensive experience managing large labs, analytical equipment, and serving external users. The NSF-funded OSU Marine Geology Repository will house the XRF scanner, efficient for application to one of the nation's largest core archives and complementing existing tools including Geotek multisensing core logging tracks and medical CT-scanner. These tools will serve the OSU, regional, national and international research communities. Availability of advanced high-resolution sensing tools will support data-intensive projects consistent with modern "big data" initiatives like NSF's EarthCube. Specific research programs that the instrument will immediately catalyze include: 1) Reconstructing the Quaternary history of the Greenland, Cordilleran, Laurentide and Antarctic ice sheets and their sensitivity to global warming using existing and new sediment archives. 2) Paleoclimate studies of ocean climate adjacent to these ice sheets, tropical Pacific changes and their impact on the carbon cycle, and late-Holocene seasonal to century-scale changes in the high latitudes, all of which are to determine the range of natural variability relative to recent deviations. 3) Construct seasonal to century-scale changes in Earth's critical zone that extends from the top of vegetation to the base of weathered bedrock upon which humanity depends and is impacting. 4) Investigate preindustrial paleoenvironments and human-landscape interactions, a baseline for recent critical zone changes. 5) Document the frequency and severity of past earthquakes in the Pacific Northwest and their impacts on the critical zone. |