Partnering Princeton and Geneva to lead community advancements in geochronology

U-Pb geochronology is the most widely applicable and accurate tool for measuring  ages of rocks and reconstruct rates of geologic processes, from the formation of the solar system, to mass extinction events, and recent volcanic eruptions. Advances in sample preparation methods, isotope measurement, and data reduction have led to increasingly more precise dates. At the same time, higher precision has lead to questions about the fundamentals of isotope systems in mineral structures, requiring development and refinement of scientific concepts.  As a result of these advances and new questions, arises the need for interaction between different laboratories to share ideas and data, formulate new methodologies, and identify areas for progress.  Princeton and UNIGE host two of the worlds' top laboratories specializing in high-precision U-Pb geochronology. As part of the EARTHTIME initiative, between ~2003 and 2010, there was a burst of interaction between different U-Pb laboratories that resulted in more precise and more accurate dates being generated, with better reproducibility between labs. Following a lull of ~7 years, there is a need again for labs to get together and pave the way to the next level of precise U-Pb geochronology. Questions surrounding climate change and Earth system history in deep time demand more precise and more accurate dates from labs such as ours. In order to facilitate this work, we propose to host and heavily subsidize two workshops at PU and UNIGE, at which representatives from established and new U-Pb labs around the world will come together for a period of 3 days each in order to determine the next steps in improving analysis and interpretation techniques, formalize an intercalibration experiment between labs, work with industry to develop better measurement tools, and to develop new strategies for outreach. The vast majority of the requested budget is to fund these two workshops, from which PU and UNIGE, as well as the broader community, will benefit significantly.   Participants Prof. Blair Schoene Princeton University, Geosciences Prof. Urs Schaltegger University of Geneva, Earth Sciences