SCATTER - Investigating a potential systematic link between the flux of cosmic material and Earth’s orbital eccentricity throughout the Phanerozoic.

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Cyclostratigraphy has been a highly valuable tool for creating precise age-depth models and understanding paleoclimate dynamics for several decades now. More recently, cyclostratigraphic research has been increasingly used for a range of applications beyond these traditional uses. Here, we evaluate a potential link between Milankovitch cycles and cosmic dust throughout the Phanerozoic. Numerical modelling of Earth’s orbital motion suggests that, on 100,000-year timescales, Earth’s capture rate of cosmic dust varies by a factor of 2 to 3 and anti-correlates with Earth’s orbital eccentricity. To date, reconstructions of the extraterrestrial flux to Earth during the Phanerozoic are hindered as each of the chemical and physical tracers currently used, is riddled by its own set of limitations. By comparing well-studied Phanerozoic and Cenozoic sections and adding a novel proxy (fossil micrometeorites), this project aims to clarify the relation between cosmic dust and changes in the orbital eccentricity of the Earth, both in the recent and deep geological past. Fossil micrometeorites are abundant and can be recovered from the geological record by dissolving large volumes of sediments or sedimentary rock (~4 kg/sample) following recently established protocols. If periods of enhancement can systematically be identified, specific dust source regions may be defined based on oxygen isotope systematics, after which shorter-term, stochastic effects will be filtered out of the obtained data sets, and the potential relationship between extraterrestrial flux and eccentricity tested.