Transport times and ages of Quaternary fine-grained terrestrial sediments using U series isotopes

点击翻译按钮获取中文摘要

This project will evaluate uranium isotope ratios of clastic sediments as a measure of thetime required for bedrock to be reduced to small grains by weathering, and thentransported and deposited as sediment. The method may open up new ways of studying andunderstanding sediments, the processes that produce them, and how sedimentary processesare dependent on climate and tectonics. Detailed physical and chemical characterizationof natural sediment from well-controlled environments will be combined with isotopicmeasurements. Fieldwork consists of collecting samples of terrestrial sediment fromlakes, loess deposits, streams, and alluvial fans. The work is designed to furtherevaluate the approach and also investigate variations in sediment transport time as afunction of climate and depositional environment. The combination of U-series isotopesand cosmogenic nuclides (Be-10 and Al-26) may yield information about timescales of soilgeneration, erosion, transport, and storage, and may allow important types of continentalsedimentary deposits to be dated. Intellectual merit: The research will contribute tounderstanding of fundamental aspects of sedimentology and landscape evolution. The PI has28 years experience in geochemical research, an extensive publication record, and hastrained more than twenty Ph.D. students who have gone on to successful careers inacademia, government, and private industry. U.C. Berkeley has a long record of support ofadvanced scientific research, and provides ample facilities, support personnel, andinfrastructure for research and graduate education. Broader Impacts: The research hasbroad applicability to geology and environmental studies. It requires knowledge andtraining in mass spectrometry, analytical and nuclear chemistry, and hence is an excellentvenue for advanced education. The funding will help support a research facility that, inthe previous 15 years, has benefited 22 graduate students (10 women) 10 postdoctoralfellows (5 women), plus more than 20 visitors, undergraduates and collaborators.