Development and applications of high precision U-Pb geochronology for earth and planetary sciences

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The focus of this research is the application of high precision uranium-lead (U-Pb) geochronology to better understand Earth history and the early development of the solar system. The U-Pb system is the most powerful geochronometer partly because determination of precise ages in Precambrian minerals requires only knowledge of the daughter Pb isotopes. Zircon is the most useful mineral for dating terrestrial rocks but its potential for producing ages of the highest possible precision has not yet been fully realized. This proposal is to develop efficient methods for extraction of Pb from zircon and accurate isotopic analysis so as to produce 207Pb-206Pb ages on Precambrian rocks that are an order of magnitude more precise than possible by conventional methods (+/-0.1 Ma instead of +/-1 Ma). This will involve new variations on methods of Pb evaporation and the use of the Neptune Plus, a new multi-collector plasma mass spectrometer with unprecedented sensitivity. The new techniques along with conventional methods will also be applied to dating meteorites and their components, such a silicate chondrules and calcium-aluminum-rich inclusions, to understand early processes of planet formation.